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Beginners, Training & Tutorials => Tutorials => Topic started by: Jknuth on July 11, 2007, 12:27:56 AM

Title: Making a Simple Rock Mold with Silicone Caulk
Post by: Jknuth on July 11, 2007, 12:27:56 AM
Ok well we will give this a shot.
I will demonstrate the techniques i use for molding simple objects using silicone caulk.

Things you need

1. silicone caulk (it must say 100% pure silicone) I use clear, but in a bind others colors will work
2. Dish soap (dawn)
3. small disposable brush
4. acrylic paint, any color will work but i use white or bright green.

first Ill explain the properties of silicone caulk.
many think it is simply air dry like most paint. this is not the case. It is condensation cured silicone, meaning water is its catalyst.
if you put it on to thick it will cure on the outside due to moisture in the air. but it will form a pocket of liquid silicone that can last years.
since it is impossible to add water to silicone by itself due to the way liquid silicone repels water. I have learned to use acrylic paint as a fast curing catalyst for caulk.
With this method it is possible to mix an entire tube of silicone with a few drops of paint and from a ball the size of a softball that will set in 45 minutes, thus eliminating the "thickness" issue.

Another issue with silicone is its adhesive properties. It is one of the stickyist substances in its liquid form. once it is cured however there are few things that it will stick to.
this is why when working with liquid silicone I use dish soap diluted with water to move the silicone around.

A few notes before i get started.
Like i said above silicone does not stick to much, but it will adhere to other Silicone, occasionally glass. Some rocks do contain natural glass and the silicone will stick to it.
I recommend using petroleum jelly to oil the rock before you begin.

Ok so we begin

first grab a rock

 
Title: Re: Making a simple mold in silicone caulk (photo tutorial)
Post by: Jknuth on July 11, 2007, 12:29:36 AM
next Brush on the silicone.
for the first coat i use PURE silicone out of the tube. we are making a thin base coat to hold the detail.
I use a brush to push the silicone into the cracks and crevices of the stone.
Title: Re: Making a simple mold in silicone caulk (photo tutorial)
Post by: Jknuth on July 11, 2007, 12:31:48 AM
after the stone is covered in a thin layer of caulk we will work on smoothing it out, and forcing any air out.
Title: Re: Making a simple mold in silicone caulk (photo tutorial)
Post by: Jknuth on July 11, 2007, 12:35:57 AM
next step mix up a cup full of dish soap and water half and half.
here is where it is interesting. Dip your fingers in the dish soap solution. Be sure to cover your fingers and hands in in the soap.
as long as your fingers are wet they will not stick to the silicone.
and remember not to worry about water on the surface. it will actually help it sure faster.
begin smoothing your fingers over the surface of the silicone. Force out any air and make sure it is a uniform thickness.
for this mold it is less then an 1/8 of an inch.
Title: Re: Making a simple mold in silicone caulk (photo tutorial)
Post by: Jknuth on July 11, 2007, 12:38:20 AM
finally you will end up with a stone with a smooth layer of silicone over the surface. let this layer set before you work any further, This is your detail coat so you dont want any gooey pockets in there.
I am going to let this sit over night and start up again in the morning. but in most cases it wont take longer then 2 hours to set. perhaps much less.
Title: Re: Making a simple mold in silicone caulk (photo tutorial)
Post by: weasel on July 11, 2007, 12:47:43 AM
WOW thank you very much i got a project i'll need this for in upcomeign snake mount i love thsi forum because through the few scammers there tons and tons of nice people willing to share thier knowlede.
just wanted to thanks you,
colt s
Title: Re: Making a simple mold in silicone caulk (photo tutorial)
Post by: Jknuth on July 11, 2007, 01:00:45 AM
Aghh forget sleep I want to see this through :D

next step.
thickening the mold
this is where it gets fun :D
add a small amount of acrylic paint to a cup full of silicone. just a drop. Unfortunately there isn't a hard formula for this, as it depends on temperature and humidity.
It will set FAST! faster then you think
Title: Re: Making a simple mold in silicone caulk (photo tutorial)
Post by: Jknuth on July 11, 2007, 01:01:42 AM
Mix it to a uniform Booger green :D
and get ready!. did i mention it sets FAST!
Title: Re: Making a simple mold in silicone caulk (photo tutorial)
Post by: Jknuth on July 11, 2007, 01:05:08 AM
next scoop it on top of the first coat of silicone.
the bright color helps in 3 ways.
1. making sure your mix is thorough
2. you will never loose another mold in the shop
3. it just looks COOL
 
Title: Re: Making a simple mold in silicone caulk (photo tutorial)
Post by: Jknuth on July 11, 2007, 01:09:45 AM
finally smooth out the silicone blob.
use the same technique as before soapy hands, work out any bubbles and make sure it is thick enough not to tear on you.
Silicone caulk is far from a permanent mold so you have to take care of it and dont be too rough. although the tube of caulk cost me $2.50 and i havnt even used half. so thats not bad for a mold. plus in the middle of the night if you want to make a mold and dont have any good silicone left you can go to walmart and get ready to mold a rock on a whim. Now who in their right mind would do such a thing??
MMMMM shrek nugget
Title: Re: Making a simple mold in silicone caulk (photo tutorial)
Post by: weasel on July 11, 2007, 01:42:07 AM
any acrillic paint will do right i got some leftover "kings gold" walmart 50cent stuff..... anyhow ever do more coats than that? or is it really not needed...especially on large set of horns and such.
Title: Re: Making a simple mold in silicone caulk (photo tutorial)
Post by: Jknuth on July 11, 2007, 02:32:11 AM
any acrylic paint will do. I have made it thicker but it isn't always necessary. I have not molded horns yet with this method, but i see no reason why it wouldn't work.
 
Title: Re: Making a simple mold in silicone caulk (photo tutorial)
Post by: Jknuth on July 11, 2007, 03:04:00 AM
well here we are. the mold is done
and I am about to demold.
just flip over the rock and begin to slowly pull off the mold, work slowly to make sure it isnt sticking anywhere. Silicone caulk has a relatively low tear strength so move slow here.
Title: Re: Making a simple mold in silicone caulk (photo tutorial)
Post by: Jknuth on July 11, 2007, 03:05:48 AM
and there ya go mold removed.
The whole process took about 2 hours. with actual  work time of about 15 minutes. cost around $1.75
mold will last many pulls. and will outlast latex.

Title: Re: Making a simple mold in silicone caulk (photo tutorial)
Post by: Jknuth on July 11, 2007, 03:40:15 AM
I cant seem to stop here :D
nest steps fill with your favorite resin. I used thinned bondo and just rolled it around inside until it set up.
a real shell casting.
Title: Re: Making a simple mold in silicone caulk (photo tutorial)
Post by: Jknuth on July 11, 2007, 03:42:31 AM
finally results!
the finished cast is demolded and painted. In this case a fiarly simple dark wash that was steel wooled off. then washes and highlights added.
and presto.
If anyone has any other questions let me know. Ill be glad to help if i can.
Title: Re: Making a simple mold in silicone caulk (photo tutorial)
Post by: Rick Krane on July 11, 2007, 06:03:39 AM
Hey Josh!

What a terrific essay on makewing a mold! This is outstanding in value to many! I'm glad you and folks like Don P share your gifts! I just wanted to say thanks for being a good teacher!

Rick
Title: Re: Making a simple mold in silicone caulk (photo tutorial)
Post by: Polymer Guy on July 11, 2007, 07:26:18 AM
Very nice posting, I'm impressed.  That process will work very well.  I have done similar things throughout the years but did use water as the catalyst and you are right, it doesn't go into solution very well.  I whip it real well and then dump the access water out.  Then smooth it onto the surface with my finger while wearing a latex glove.  I love the use of the dish soap and water to smooth it out.  I have never done that before.  Cool trick and again, great posting!
Title: Re: Making a simple mold in silicone caulk (photo tutorial)
Post by: after the shot on July 11, 2007, 08:00:13 AM
Great post. Thank you.
Title: Re: Making a simple mold in silicone caulk (photo tutorial)
Post by: Debbie C. on July 11, 2007, 08:19:43 AM
i'm gonna be trying this --- Thanks ;D
Title: Re: Making a simple mold in silicone caulk (photo tutorial)
Post by: mshipman on July 11, 2007, 08:47:23 AM
Thanka for sharing very helpful
Title: Re: Making a simple mold in silicone caulk (photo tutorial)
Post by: Glenn on July 11, 2007, 09:16:15 AM
Info is much appreciated.  Thank you.
Title: Re: Making a simple mold in silicone caulk (photo tutorial)
Post by: Jknuth on July 11, 2007, 12:01:40 PM
Good I am glad I can help. I get so much help from everyone on this forum, its nice to return the favor. :D
Title: Re: Making a simple mold in silicone caulk (photo tutorial)
Post by: Dondi on July 11, 2007, 12:55:01 PM
Josh,
 Great post ! ....Even better when you look at the cost of imitation rocks in the catalogs $$$
Title: Re: Making a simple mold in silicone caulk (photo tutorial)
Post by: Jknuth on July 11, 2007, 01:01:00 PM
Thats for sure. plus you can pick your own rocks for display. I have even done this on a larger scale molding a rock that was 3 feet wide. it took a bit more silicone :D but it worked
Title: Re: Making a simple mold in silicone caulk (photo tutorial)
Post by: AndyB on July 11, 2007, 02:14:54 PM
great step by step very detailed i appreciate it very much thank you
Title: Re: Making a simple mold in silicone caulk (photo tutorial)
Post by: fesekula on July 11, 2007, 02:33:41 PM
I am headed back to walmart for caulking to give your tips a try. Great post, thank you!
Title: Re: Making a simple mold in silicone caulk (photo tutorial)
Post by: rnviper3 on July 11, 2007, 05:48:03 PM
fantastic lesson.  thanks for sharing.  sometime you have to see pictures to really get it.  thanks again for taking the time to post for all us needing to know. 
Title: Re: Making a simple mold in silicone caulk (photo tutorial)
Post by: Pascal on July 11, 2007, 08:13:35 PM
Wow! That was a great post. Thanks so much for taking the time and effort to detail this process. Big money saver. Thanks again.
Title: Re: Making a simple mold in silicone caulk (photo tutorial)
Post by: weasel on July 11, 2007, 09:37:54 PM
WOW i made a mess..maybe the the egg and small pecans were to small.
Title: Re: Making a simple mold in silicone caulk (photo tutorial)
Post by: Jknuth on July 11, 2007, 11:05:20 PM
LOL
it didnt work for ya?
Title: Re: Making a simple mold in silicone caulk (photo tutorial)
Post by: Terry Vining on July 11, 2007, 11:44:51 PM
I know that two part silicone and latex gloves  can give you curing troubles. I don't know if it's a problem with the tube silicone. I always use the nitrile type when working with silicone.
Title: Re: Making a simple mold in silicone caulk (photo tutorial)
Post by: weasel on July 12, 2007, 12:04:14 AM
LOL
it didnt work for ya?
it prob would have but the egg broke even though being froze the silicone wasn't 100% all my 100% was one rubber chunk....lol i made a huge mess of it i jsut decided to find some small pecans and paint them and hope thats good enough lol....i'm sure it'll work for me easier on bigger stuff.
Title: Re: Making a simple mold in silicone caulk (photo tutorial)
Post by: mark11 on July 15, 2007, 03:20:08 AM
Would this work in molding a frozen specimen? I mold all of my own artificial duck and goose heads and would like to find an inexpensive way to make the first mold. I currently mold the head in RTV and then clean up and repair the cast and then remold in RTV to get a production mold. Thanks, Mark.
Title: Re: Making a simple mold in silicone caulk (photo tutorial)
Post by: montana art on July 15, 2007, 11:32:20 PM
just got back from vacation. Thanks so much for the info. great article!
Title: Re: Making a simple mold in silicone caulk (photo tutorial)
Post by: Jknuth on July 16, 2007, 12:02:42 AM
I havnt tried it with totally frozen specimens.
I have seen it used to mold duck heads and geese  in the field. the trick is not to get it on any feathers.
we actually skinned the ducks head back to the neck first, I say we because i am not a bird guy.
I have molded Iguana heads after they where skinned to make a carcass cast. they where cold but not frozen.
Title: Re: Making a simple mold in silicone caulk (photo tutorial)
Post by: mark11 on July 18, 2007, 05:05:08 PM
Thanks, I will try it both ways and get back when I do to let anyone interested know how it works out. Mark
Title: Re: For more detail
Post by: boarhunter67 on July 18, 2007, 09:51:24 PM
For some items (like bison horns) I've thinned out the silicone with xylene on the first coat only.  Also, using synlube will make it release better on things like that.   Thanks for the acrylic tip.  I get tired of waiting for it to try.  :)
Title: Re: Making a simple mold in silicone caulk (photo tutorial)
Post by: Oráiste on July 19, 2007, 11:41:44 AM
Thanks for this. Great idea with the bright paint! =) Will be trying after my holidays.
Title: Re: Making a simple mold in silicone caulk (photo tutorial)
Post by: -Rebecca- on July 21, 2007, 10:53:53 PM
Thanks for the great post! I tried it out on some shrooms and it worked great. 
Title: Re: Making a simple mold in silicone caulk (photo tutorial)
Post by: Jknuth on July 22, 2007, 02:27:22 AM
Thanks for the great post! I tried it out on some shrooms and it worked great. 

YAAY Iam useful LOL

Iam glad it worked out
Ill be posting a photo of what i used the rocks for in a few day. just have a few more finishing touches :)
Title: Re: Making a simple mold in silicone caulk (photo tutorial)
Post by: michaelj on July 22, 2007, 09:18:46 AM
Joshua, thumbs up to an EXCELLENT tutorial.
Can you expand on how you colored the rock?
Thanks again.
Title: Re: Making a simple mold in silicone caulk (photo tutorial)
Post by: Samantha. on July 22, 2007, 07:33:14 PM
Josh - Thankyou so much.
Repro rocks are just too unaffordable for me to bring over here.
I havnt been confident enough to try and mold some real ones myself until I read your post.

Now I just have to find a sales person at the hardware store who knows what he is selling. When I asked for 100% silicone in tubes - well, he just gave me a blank look. :) ::)
Title: Re: Making a simple mold in silicone caulk (photo tutorial)
Post by: SB7 on July 23, 2007, 04:38:58 AM
Jknuth

           
Quote
"I used thinned bondo"
 
             
             I'm new to this forum,   
            
             Please explain WHICH PRODUCT OF  BONDO   ??? you purchased.
             Also is this the same BONDO that you can purchase at an AUTO PARTS STORE???
             
             Please explain how you THINNED IT??? 
Title: Re: Making a simple mold in silicone caulk (photo tutorial)
Post by: SB7 on July 23, 2007, 05:56:05 AM
Samantha.

   
Quote
               Now I just have to find a sales person at the hardware store who knows what he is selling. When I asked for 100% silicone in tubes - well, he just gave me a blank look. 


                         
                             You can purchase what your looking for at the following two stores...... HOME DEPOT or LOWES

                 Look SPECIFICALLY for the following item.   
                                                                                 GE    (General Electric Emblem)

                                                                                 SILICONE 1

                                                                                 100% SILICONE RUBBER SEALANT

                                                                                 CLEAR

           The product you want, Is Packaged in a RED COLORED TUBE.....  Purchase the RED COLORED TUBE ONLY Its marked Specifically for KITCHEN & BATH  (WRITTEN IN WHITE) on the side of the Caulking tube.
           
           Wonder the isles until you find it, if you have to, most likely it will be in a single box consisting of a dozen or so tubes.
           
           It also comes in a small squeezable plastic tube dispenser with a cap cover.  ALSO COLORED RED

            The tube is a CAULKING TUBE so you will also need to purchase a rather inexpensive [b]CAULKING GUN[/b],  ask the salesperson how to use it.
            You don't have to be a rocket scientist.

                                                                           _________________

           You will also find the same product packaged in a BLUE COLERED TUBE...........DO NOT PURCHASE THIS COLOR [/b] as it is OUT OF DATE, contents expired.

           You will find this color packaged tube amongst a great variety of tubes....    ALL ....will be in the same immediate vicinity....  All ....wil be the same color.  This alone will tell you your in the wrong isle.   

          AGAIN ITS OUT OF DATE STAY AWAY FROM THIS COLORED PRODUCT



                                                         Hope this helps

                                                               SB7
Title: Re: Making a simple mold in silicone caulk (photo tutorial)
Post by: Jknuth on July 23, 2007, 12:51:38 PM
Iam not sure if they have lows or home depot in the land down under? but just make sure it says 100% silicone and not Siliconized caulk.

Hey where are you from in the AU ? my wife spent a summer in Brisbane and Sydney a few years back. she never stops talking about how much she loved Brisbane!
she desperately wants us to move there!!
Title: Re: Making a simple mold in silicone caulk (photo tutorial)
Post by: Jknuth on July 23, 2007, 12:55:11 PM
Jknuth

           
Quote
"I used thinned bondo"
 
             
             I'm new to this forum,   
           
             Please explain WHICH PRODUCT OF  BONDO   ??? you purchased.
             Also is this the same BONDO that you can purchase at an AUTO PARTS STORE???
             
             Please explain how you THINNED IT??? 

Bondo auto body filler
and polyester resin
at a ratio from b50/p50  to b60/p40
I use the hardener for both. and i try to find white hardener. some auto body suppliers carry it some dont. I think WASCO sells it.
Title: Re: Making a simple mold in silicone caulk (photo tutorial)
Post by: SB7 on July 24, 2007, 03:41:26 PM
Joshua:

          I'm reside in the land of sunhine and surf, Clearwater, Florida!!!.  Was unaware that Samantha was from the land down under...OZ!

          Thanks for the heads up pertaining to Siliconized caulk, never heard of it before??? ???
         


         Likewise thanks for the info pertaining to

         
Quote
  Bondo auto body filler
and polyester resin
at a ratio from b50/p50  to b60/p40
I use the hardener for both. and i try to find white hardener. some auto body suppliers carry it some dont. I think WASCO sells it.

    Most all the stores in my area carry this product.   Will make it my business to get it!


                                Henry

Title: Re: Making a simple mold in silicone caulk (photo tutorial)
Post by: Nate Miller on July 24, 2007, 10:32:35 PM
that is one awsome tip!! i know what i'll be doing this weekend!! LOL!! is there any way to thin that to a pourable to mold like the inside of a fish mouth?
Title: Re: Making a simple mold in silicone caulk (photo tutorial)
Post by: Jknuth on July 24, 2007, 11:45:27 PM
that i dont know. if you find out please let me know. perhaps thinning it with xylene?
Title: Re: Making a simple mold in silicone caulk (photo tutorial)
Post by: Samantha. on July 25, 2007, 09:16:13 AM
Iam not sure if they have lows or home depot in the land down under? but just make sure it says 100% silicone and not Siliconized caulk.

Hey where are you from in the AU ? my wife spent a summer in Brisbane and Sydney a few years back. she never stops talking about how much she loved Brisbane!
she desperately wants us to move there!!

No - we have neither store. We do have a few others though. I'm sure they hate me as I tend to go in there and say "some people in America told me....yada, yada, yada"  ;D
Thanks for the tip about the caulk........almost picked 1 up yesterday.
Ok - at present I live near Melbourne which is about 1000 kilometers south, (about 8-9 hour drive), from sydney and a 23 hour drive from Brisbane. :)
Dont come here........there's not much choice in animals to work on  ;) ;D
Brisbane is alright though. Nice tropical weather, beaches, fishing & hunting.

SB7 - I'm not a rocket scientist , but I am well aware of what a caulking gun is, thanks. ::)
/
............................   Avatar. Kangaroo = Australian.
\
Title: Re: Making a simple mold in silicone caulk (photo tutorial)
Post by: SB7 on July 25, 2007, 03:40:17 PM
Samantha.

               Should you not be able to locate 100% Silicone!
               
               If you want I can find out how much it would cost to ship a tube to you book-rate? Which I believe is the slowest as well as cheapest way to ship!.
               More than happy to send some down under for you?.

               The tube itself is under $5.00 American.

               Whatever the price is I'm pretty sure it'll be a lot cheaper then RTV likewise Vacuuming or Pressure Tanks Expenditure/Outlay
                                                         

              SB7

 Joshua

             What would you use to thin out the BONDO?
     
             And if it is Xylene? ??? where would I go about obtaining this material????? ???

             How or under what conditions would the Xylene be used????

             And is there a MSDS ??? sheet available for this material ???

                          Well ventilated area?
                          wear a respirator?
                          Wear gloves?
                          ETC
Title: Re: Making a simple mold in silicone caulk (photo tutorial)
Post by: Jknuth on July 25, 2007, 04:49:00 PM
Xylene is found at most paint supply stores.
I know it will weaken the silicone some.
Also
IT IS VERY TOXIC!
be very careful
use a respirator and only in a ventilated area.

Ill check on some specs for thinning it.
Title: Re: Making a simple mold in silicone caulk (photo tutorial)
Post by: Samantha. on July 25, 2007, 07:05:20 PM
Hey thanks for the offer SB7.
I will go through a few more stores before I seek assistance. :)
Unfortunately the US has stopped the surface mail service to us a few weeks back. Airmail being the only way for us to get stuff now. Thats fine but too bad if we want something that cant be shipped via air.
Title: Re: Making a simple mold in silicone caulk (photo tutorial)
Post by: boarhunter67 on July 28, 2007, 06:30:33 PM
You use xylene to thin out silicone.  You use fiberglass resin (polyester) to thin out bondo. 
Title: Re: Making a simple mold in silicone caulk (photo tutorial)
Post by: Nate Miller on July 29, 2007, 09:47:08 AM
thanks guys. i'll give the xylene a shot. would'nt it be better to use the formula to mold the inside of a fish mouth than spending all that money on RTV silicone. just one mans opinion. by the way Josh i molded and cast my first rock and duck head yesterday, that method is nothing short of amazing, THANKS!!
Title: Re: Making a simple mold in silicone caulk (photo tutorial)
Post by: Jknuth on July 30, 2007, 01:23:34 AM
well here are the rocks put to good use. at some point Ill do a thing on painting rocks if there is any interest.
(http://www.knuthart.com/rock1.jpg)
(http://www.knuthart.com/rock2.jpg)
Title: Re: Making a simple mold in silicone caulk (photo tutorial)
Post by: SB7 on July 30, 2007, 06:08:42 PM
Hello boarhunter67

      

   
Quote
You use xylene to thin out silicone.  You use fiberglass resin (polyester) to thin out bondo


   You stated that You use fiberglass resin (polyester) to thin out bondo. 

   Does this mean that you can thin the Bondo (fiberglass resin) to the point that it will liquify and (freely) pour, likewise still maintain its hardening strength....  and If so to what ratio.  ???


                                     SB7

 
Title: Re: Making a simple mold in silicone caulk (photo tutorial)
Post by: Barry on July 30, 2007, 06:10:16 PM
Trust me there is interest for some of us Please post it when possible! Those are magnificent Thanks for sharing
Title: Re: Making a simple mold in silicone caulk (photo tutorial)
Post by: Jknuth on July 30, 2007, 06:28:00 PM
The xylene will thin the silicone, but not to pourable constancy. It will also weaken the rubber somewhat.

Ill be working on another project with rocks in the near future Ill do another series on painting and attaching a mount.
It will be a wall mount Sauger over rocks attached by a fin.
Title: Re: Making a simple mold in silicone caulk (photo tutorial)
Post by: ccook63 on July 31, 2007, 10:44:20 PM
Absolutely the best tip I have heard in a long time. Thank's for sharing
Title: Re: Making a simple mold in silicone caulk (photo tutorial)
Post by: Samantha. on August 01, 2007, 08:15:18 AM
At some point Ill do a thing on painting rocks if there is any interest.

(http://www.freewebby.com/happy-smilies/yes.gif)
Title: Re: Making a simple mold in silicone caulk (photo tutorial)
Post by: Becky P on August 01, 2007, 08:31:34 AM
Thanks for the great tutorial, esp. the paint/silicone setting tip ;)
Title: Re: Making a simple mold in silicone caulk (photo tutorial)
Post by: mk on August 01, 2007, 08:58:34 AM
The xylene will thin the silicone, but not to pourable constancy. It will also weaken the rubber somewhat.

Ill be working on another project with rocks in the near future Ill do another series on painting and attaching a mount.
It will be a wall mount Sauger over rocks attached by a fin.

that would be real cool.
Title: Re: Making a simple mold in silicone caulk (photo tutorial)
Post by: Joey Arender on August 01, 2007, 11:17:25 AM
 Can't wait for the painted tour....I will be using this into the future for sure, until now I been pouring money all over the rocks. I like how simple your method is and cheap
 thanks for taking the time to share
Title: Re: Making a simple mold in silicone caulk (photo tutorial)
Post by: boarhunter67 on August 01, 2007, 06:44:52 PM
The xylene is good to use to thin out the first coat if you are making something with extremely fine detail like the hair pattern on bison horns, which is what I make copies of occasionally.  You don't pour it on; you paint it on, then switch to straight silicone with the acrylic paint.  After several layers, it's plenty strong. 
Thanks again for the tips.  I can't wait to see the painting.
Title: Re: Making a simple mold in silicone caulk (photo tutorial)
Post by: spcantwell on August 02, 2007, 10:02:58 AM
could this method be used to do a quick simple closed mouth fish head?
Title: Re: Making a simple mold in silicone caulk (photo tutorial)
Post by: Jknuth on August 02, 2007, 10:59:25 AM
It can be done on fish heads. the only trick is making sure the skin is dry to the touch or at least a bit tacky.
but this is true with most silicone fish head molds.
Title: Re: Making a simple mold in silicone caulk (photo tutorial)
Post by: boarhunter67 on August 04, 2007, 12:06:47 AM
Also for some items (such as bison horns) you'll want to use a releasing agent like syn-lube.   I use it all the time and it's a spray. 
Title: Re: Making a simple mold in silicone caulk (photo tutorial)
Post by: Virginiajoe on August 10, 2007, 05:25:52 PM
Hello there all these material are non toxic??  and safe for the earth. Im kind newbie
Title: Re: Making a simple mold in silicone caulk (photo tutorial)
Post by: rocky don on August 10, 2007, 05:45:08 PM
what in the world do you mean good for the earth? your casting a rock dude!!
Title: Re: Making a simple mold in silicone caulk (photo tutorial)
Post by: jeremy on August 17, 2007, 12:47:39 PM
Great post, thanks. I wish I would of saw it 3 days ago before I orderd my rtv from vandykes as im now going to try to cast my duck heads. Well now I know.
Title: Re: Making a simple mold in silicone caulk (photo tutorial)
Post by: Bakes on August 18, 2007, 09:53:44 AM
Well I just moulded a rock using this method then I went back and read the instructions.  ;D
Demoulding was a right bastard and now I know why. The rock I used had some quartz in it and the bloody silicone stuck to those bits (should of put a release on it :-[) But never mind I can patch any dodgy bits on the mould. I'll cast it tomorrow. Going to use it for a snake hide ;)
Title: Re: Making a simple mold in silicone caulk (photo tutorial)
Post by: Matt G on August 20, 2007, 09:49:10 AM
I just made a reproduction set of antlers of a average rack that my Grandpaw had killed.  I have to say that this method captured absolutely every detail and looks great.  I used smooth-on 320 for the casting.  The only thing I noticed was that the casting diameter of the horns were slightly smaller than the real horns, kind of like the silicone mold shrank a little.  It wasn't bad enough to hurt though.  What would keep the mold from shrinking like that?  I also had difficulty making the mothermold because I couldn't get anything to stick to the silicone.  I eventually gave up on the mothermold and simply created a wooden jig to hold the horns and its points all in place.  It worked pretty good, but set up time was a killer.
Title: Re: Making a simple mold in silicone caulk (photo tutorial)
Post by: Tereza Revis on August 25, 2007, 03:34:14 PM
Thanks for sharing your knowledge and skills.  Great info and easy to follow.  You are a great teacher.
Title: Re: Making a simple mold in silicone caulk (photo tutorial)
Post by: BeckyBird on August 26, 2007, 02:03:58 AM
Thank you SO much for this wonderful post. It was so nice of you to take the time and share your technique. I have heard about this method, but to see it  step-by-step is very helpful!
Title: Re: Making a simple mold in silicone caulk (photo tutorial)
Post by: Gunny on September 01, 2007, 02:44:36 AM
nice
Title: Re: Making a simple mold in silicone caulk (photo tutorial)
Post by: dbess on September 08, 2007, 10:52:54 AM
I just used this method on a native brook trout....with a tiny head.....worked like a charm...thanks for posting such great info!!!!!!
Title: Re: Making a simple mold in silicone caulk (photo tutorial)
Post by: Jknuth on September 09, 2007, 02:14:37 AM
WOW dbess I would like to see how it turned out. Any pictures?
Title: Re: Making a simple mold in silicone caulk (photo tutorial)
Post by: muleyhunter on September 17, 2007, 08:55:41 PM
Josh,
I had to post something to be able to go back for reference. Ypu have done such a great job on this.
Title: Re: Making a simple mold in silicone caulk (photo tutorial)
Post by: John L on September 19, 2007, 05:59:01 AM
Can you mold and replicate a fish this way?   I have heard of people using bondo but not sure how that works.

John
Title: Re: Making a simple mold in silicone caulk (photo tutorial)
Post by: FloridaGirl on September 19, 2007, 06:24:19 PM
I can't wait to try this.
Title: Re: Making a simple mold in silicone caulk (photo tutorial)
Post by: Jknuth on September 20, 2007, 12:48:48 AM
I would still use the bondo method on fish.
the results are great.
however I have used this caulk method to mold the interior of the mouth on fish.
Title: Re: Making a simple mold in silicone caulk (photo tutorial)
Post by: petes on September 20, 2007, 03:52:34 AM
silicon for me

i only used it as a 'back up 'to expensive  rtv that we have
. yes it sticks to each other  since  its the  same family of silicon.
so it save you a lot on rtv.

to pick up very detail stuff use rtv ,jsut the surface.
then followed by   silicon is use as  the 'back up.'-thickening process.

i only air dried the silicon.- took me idle time,
joshua you have given me tips how to quicken the process- thank you

i sometime also use  burlap to apply to silicon if a stronge  mold is needed.
many types of rubber  are formulated  to specifially   pick up details.
thats why they are expensive rubber..
while some rubber are cheapy like the silicon,
 but   at least they are fleixble to begin with unike rtv that is expensvie..
 and for me it only  serve as   a back up.- im talking about mold
that is for long time use  . not only one time.

i even heard, silicon sticks to cheap latex-and vice versa

xxxxxxxx

as to thining bondo,

i use  styrene
works  fine

this is pete- saying hello to  joshua and to all.  !!!! :)

HAPPY CASTING !
Title: Re: Making a simple mold in silicone caulk (photo tutorial)
Post by: TMALONE on September 24, 2007, 07:15:27 PM
This is great stuff, thank you very much for sharing!!
Title: Re: Making a simple mold in silicone caulk (photo tutorial)
Post by: Jerry Conway on September 26, 2007, 10:26:52 PM
Awesome tip!! Thanks
Title: Re: Making a simple mold in silicone caulk (photo tutorial)
Post by: wesley K. on September 29, 2007, 09:31:11 PM
great tip but you never said wich rock was the real deal in the pic. lol
Title: Re: Making a simple mold in silicone caulk (photo tutorial)
Post by: Jknuth on September 30, 2007, 04:05:39 PM
nope I didnt  ;)
Title: Re: Making a simple mold in silicone caulk (photo tutorial)
Post by: giuseppe on October 03, 2007, 09:48:52 PM
you are a great teacher  thanks for sharing your knowlege alot of people can use this including myself. thanks again
Title: Re: Making a simple mold in silicone caulk (photo tutorial)
Post by: TrailsEnd on October 10, 2007, 07:03:32 PM
Nice post. I've been using latex and it takes too long to wait between coats. I am going to mold some fossil stones I have with the silicone.
Title: Re: Making a simple mold in silicone caulk (photo tutorial)
Post by: Uncle Harley on October 10, 2007, 07:32:58 PM
when mixing the silicone with paint, how long does it take to kick    and as far as a tutorial on painting rocks, I say ROCK ON I'm interested!
Title: Re: Making a simple mold in silicone caulk (photo tutorial)
Post by: Jknuth on October 11, 2007, 01:06:53 AM
the silicone will kick anywhere from 3 minutes to 10 minutes depending on how much you add.
Title: Re: Making a simple mold in silicone caulk (photo tutorial)
Post by: Wild Bill on October 19, 2007, 06:57:51 AM
Awesome thread Joshua, I have to try this. Thank you for the information !!
Title: Re: Making a simple mold in silicone caulk (photo tutorial)
Post by: Codi on November 06, 2007, 04:12:53 PM
Here's mine! I only did half a rock, because it will be half buried in dirt. I'm going to paint it tomorrow. :D Thanks for all the great rock making information Jknuth.

(http://i28.photobucket.com/albums/c219/codiwiss/myrock.jpg)
Title: So,...
Post by: Kerby Ross on November 11, 2007, 04:34:51 PM
I have used the bondo method before...but I don't like the HEAT that comes with it.  Yes, I throw it into COLD water right away..but it still damages the original specimen.

My question is:  Does the silicone HEAT up during the curing process?

Thanks

Kerby...
Title: Re: Making a simple mold in silicone caulk (photo tutorial)
Post by: Jknuth on November 11, 2007, 06:18:44 PM
Nope not at all. Stays room tmep the whole time.
Title: Thanks
Post by: Kerby Ross on November 11, 2007, 07:32:47 PM
:)

Kerby...
Title: Re: Making a simple mold in silicone caulk (photo tutorial)
Post by: taxos on November 15, 2007, 02:11:45 PM
very cool man!! but I have a question about thinning it with polyester...is this the polyester you can by in an ordinary Do-it-yourself-shop?
Title: Re: Making a simple mold in silicone caulk (photo tutorial)
Post by: djm on November 15, 2007, 10:21:16 PM
Great tutorial, greatly appreciated. Could I use this same technique on beaver stumps, if I seal them 1st?
Title: Re: Making a simple mold in silicone caulk (photo tutorial)
Post by: sparkyf on November 25, 2007, 02:42:32 PM
Thanks Josh!!  Great thread!!!
Title: Re: Making a simple mold in silicone caulk (photo tutorial)
Post by: bagumbas on November 27, 2007, 01:58:20 AM
Hey Josh
 I just want to thank you for making me and my shop busier than it already is. My 9 year old daughter read your awesome post while in my shop(i replicate antlers and horns) she came to me and wanted to give it a try. So down to our shoreline picked out 3 rocks then off to wal-mart to buy silicone and bondo. She now mass produces t-light candle holders. she has made about 125 of these things and sells them for $4 a piece. She now buys her own supplies out of her profits and is learning real quick about owning your own business. hopefully uncle sam wont get ahold of her. we never have enough and have more orders. she will soon be going back to wal-mart and buing her new wii she wants.   once again we thank you
                         Big Shot Reproductions and also Savannahs Rocks
here is a pic of her first set missed a little paint in the air bubble but i threw 2 part epoxy in there and then she touched it up
Title: Re: Making a simple mold in silicone caulk (photo tutorial)
Post by: Jknuth on November 27, 2007, 02:31:59 AM
WOW so cool!

Good for her!
Title: Re: Making a simple mold in silicone caulk (photo tutorial)
Post by: EM on November 27, 2007, 02:33:36 AM
Awwww that's awesome Bagum!  I bet she's more excited than a puppy on Christmas morning!  Good for Miss Savannah!  The rocks look dang good too there Pops.  Good job all y'all.  :)  Makes you all warm & fuzzy huh Josh?
Title: Re: Making a simple mold in silicone caulk (photo tutorial)
Post by: Jknuth on November 27, 2007, 03:10:04 AM
Awwww that's awesome Bagum!  I bet she's more excited than a puppy on Christmas morning!  Good for Miss Savannah!  The rocks look dang good too there Pops.  Good job all y'all.  :)  Makes you all warm & fuzzy huh Josh?

Corny but it does ;D

I have to ask
How is she cutting the whole in them? is she casting solid or hollow?
or is this a trade secret :D
Title: Re: Making a simple mold in silicone caulk (photo tutorial)
Post by: Becky P on November 27, 2007, 07:43:00 AM
Way to go Savannah. They look great!
Savannah's Rocks - I like that ;)
Title: Re: Making a simple mold in silicone caulk (photo tutorial)
Post by: bagumbas on November 27, 2007, 11:16:34 AM
josh its solid bondo i do drill a 1" 1/2 hole 3/4 inch deep for her she absolutely loves doing this, thanks again    ill show her your post Becky thanks    I think she's ready to make antlers  lol We now made a mold of the finished product so we dont have to drill holes in them anymore.
Title: Re: Making a simple mold in silicone caulk (photo tutorial)
Post by: Uncle Harley on November 27, 2007, 12:20:06 PM
So when are we going to see the tutorial on how to paint rocks?
Title: Re: Making a simple mold in silicone caulk (photo tutorial)
Post by: Becky P on November 27, 2007, 02:27:56 PM
How much would shipping be on a couple of those "Savannah's Rocks" rocks?  (I'm thinking Christmas presents ;) )
Title: Re: Making a simple mold in silicone caulk (photo tutorial)
Post by: Jknuth on November 27, 2007, 05:26:21 PM
Its on its way!  ;D
Ive been Way too Busy LOL
Title: Re: Making a simple mold in silicone caulk (photo tutorial)
Post by: bagumbas on November 27, 2007, 06:28:14 PM
Becky:
  This is Savannah i will sell you the rocks for $4.00 a piece including shipping.
just let me know how many you would like and your address.

                               Thank You
                                Savannah
Title: Re: Making a simple mold in silicone caulk (photo tutorial)
Post by: Becky P on November 27, 2007, 07:36:10 PM
Sent you a PM
Thanks
Title: Re: Making a simple mold in silicone caulk (photo tutorial)
Post by: kirkp on November 28, 2007, 05:14:26 PM
Well, decided I had to give it a try.  Thought I'd try it first on a replacement canvasback skull that I use for carving reference.  Got the 100% silicone on there slick as a whistle.  Then waited, and waited.  24 hours laters at 42% humidity and it's still not set up completely.  thought about dunking it in a glass of water since I seem to remember Jason saying that it was moisture cured.  Think I'll take another head tonight and just try coating it with the acrylic/silicone mix to see how it does.

Having fun though,
Kirk
Title: Re: Making a simple mold in silicone caulk (photo tutorial)
Post by: Jknuth on November 28, 2007, 05:46:13 PM
The first coat should be very thin 1/8 inch or less. then smooth it with water dishsoap mixture.
After that thin face coat sets, use the Acrylic silicone mix.

The acrylic is the carrier of the moisture, the paints gel form allows you to mix it with the silicone.
Title: Re: Making a simple mold in silicone caulk (photo tutorial)
Post by: bagumbas on November 28, 2007, 11:17:47 PM
josh tried making more molds yesterday and the silicone stuck so bad to the rocks i couldnt get it off the rock so i put zyvak mold release on the rocks and the same thing happened. i did not mix any paint in with the silicone is that the problem? because the 4 that i did mix with paint work just fine.
Title: Re: Making a simple mold in silicone caulk (photo tutorial)
Post by: Jknuth on November 29, 2007, 01:23:58 AM
Hmm
Are these the same rocks you molded before??

there are a few possibilities.

1. Exposed Quarts will bond to silicone
2. some silicone was somehow stuck to the rock and you did not see it. Silicone sticks to itself.

I use vasaline or cooking oil on my rocks, I only have sticking issues after I have molded the same rock many times, or there is quarts.

I hope that help you out
Title: Re: Making a simple mold in silicone caulk (photo tutorial)
Post by: bagumbas on November 29, 2007, 11:22:50 AM
Josh they are different rock  i'll try vaseline should i mix it with mineral spirits or straight vaseline?
Title: Re: Making a simple mold in silicone caulk (photo tutorial)
Post by: Jknuth on November 29, 2007, 02:10:49 PM
I just use it straight and rub it on with my finger to work out the surface. You dont want to fill detail spots, so it doesnt have to be thick.
Title: Re: Making a simple mold in silicone caulk (photo tutorial)
Post by: kirkp on December 02, 2007, 02:33:23 AM
Well, finally got the pure silicone to set up on my canvasback study bill.  It was only about 1/8" but it was taking forever.  Finally did put it in a glass of water figuring what could it hurt.  Now hopefully I didn't make a mistake because a response by Jason (sorry, I meant Joshua) to my last post said to apply the caulk/paint mix after the pure silicone skins over.  Hopefully I didn't make a mistake by letting it cure completely.

First batch of caulk/paint I mixed up ended up having too much paint in it.  It was amazing how fast it set up and I couldn't spread it out.  Second batch had less paint and it's on but while it "seems" to be cured, it's got a sticky feel to it.  Is this natural?  Also noticed that the paint seems to really reduce the stiffness of the silicone.

Guess we'll see how it goes tomorrow.

Kirk
Title: Re: Making a simple mold in silicone caulk (photo tutorial)
Post by: Jknuth on December 02, 2007, 04:13:47 AM
The paint will reduce the strength somewhat, anytime you add a filler or additive to a silicone it will alter its properties.
They sticky?? Give at a good cure over night that may be all it needs.

The cool thing with silicone is it sticks to itself without issue so you can wait until the first coat cures to add the second with no issue.
Title: Re: Making a simple mold in silicone caulk (photo tutorial)
Post by: kirkp on December 02, 2007, 03:05:03 PM
Well, I'm making some progress with this thing.  I took another look at the head and the silicone/paint mix had cured but it still had a "sticky" feel to it.  Guess that's just the paint effect.  I split the silicone on the top and bottom of the skull to make it easier to get out.  What I noticed is that the silicone didn't release very well.  Silicone tore loose in the nostrils and the lamillae and it also stuck in areas on the bottom of the bill.  Guess I need to get a better/real mold release.  I sprayed it with a cooking spray and it wasn't good enough.  One nice thing about the stickier nature of the silicon/paint mix is that the edges where I cut on the skull sort of healed themselves back together.  Plan on trying the casting tonight.  One question, when mixing the bondo/resin mix, is there any type of container I should avoid?

Kirk
Title: Re: Making a simple mold in silicone caulk (photo tutorial)
Post by: boarhunter67 on December 04, 2007, 10:58:21 AM
Before using silicone, spray surface with Synlube.  Don't mix in a plastic or styrofoam meltable cup.
Title: Re: Making a simple mold in silicone caulk (photo tutorial)
Post by: beresford13861 on December 04, 2007, 06:06:22 PM
wow what a grea article!!!!
Title: Re: Making a simple mold in silicone caulk (photo tutorial)
Post by: Becky P on December 24, 2007, 11:11:37 AM
bagumbas and Savannah, I received my "rocks" today. The are very nice. Thank you ;) and Merry Christmas.
Title: Re: Making a simple mold in silicone caulk (photo tutorial)
Post by: coal39 on December 24, 2007, 11:35:10 AM
Great post.Thanks so much
Title: Re: Making a simple mold in silicone caulk (photo tutorial)
Post by: Roger E on December 24, 2007, 04:55:42 PM
so why do you not use a clear plastic cup to mix the silicone?  In his reply #6, it appears that a plastic cup was used...please educate me further...thanks
Title: Re: Making a simple mold in silicone caulk (photo tutorial)
Post by: Uncle Harley on December 24, 2007, 11:06:54 PM
Bagumbas and Savannah, I too recieved my rocks today totally awsome, even more real looking in person that photos could ever show.  My wife LOVED THEM!!!
Title: Re: Making a simple mold in silicone caulk (photo tutorial)
Post by: Tom_n_Nash on January 02, 2008, 08:04:16 AM
Josh, I know it's been said many times now, but I couldn't resist adding my 2 cents as well: Thanks for taking the time to share your expertise on molding and casting. Sharing this kind of trade knowledge is what makes this site so special for all of us who work or dabble in taxidermy or nature art.  Can't wait to see your rock painting techniques. Thanks again.

Tom
Title: Re: Making a simple mold in silicone caulk (photo tutorial)
Post by: boarhunter67 on January 03, 2008, 11:27:11 AM
Sorry, don't mix your polyester fiberglass resin in plastic or the cup could melt before you pour it out.
Title: Re: Making a simple mold in silicone caulk (photo tutorial)
Post by: Roger E on January 03, 2008, 12:03:56 PM
Thanks for the tidbit.
Title: Re: Making a simple mold in silicone caulk (photo tutorial)
Post by: taxos on January 04, 2008, 05:33:29 AM
I´ve made my first cast, and it turned out above expectations! what an excellent way to make lightweight stones!! thanx alot for the tutorial!
Title: Re: Making a simple mold in silicone caulk (photo tutorial)
Post by: JL on January 04, 2008, 08:59:34 PM
I thin Bondo with lacquer thinner or acetone, and sometimes Layup resin ( for deer ears). Nice post, really informative....will be trying it out. Thanks...JL
Title: Re: Making a simple mold in silicone caulk (photo tutorial)
Post by: taxos on January 05, 2008, 11:02:07 AM
JL, that would be great to thin the bondo with, it saves up money. Resin is quite expensive. Does the thinner affectthe drying proces, and can you still use the ordinary hardener?
Title: Re: Making a simple mold in silicone caulk (photo tutorial)
Post by: DALE G on January 06, 2008, 01:48:43 PM
what about moulding pine tree bark. ever tried ?   dale
Title: Re: Making a simple mold in silicone caulk (photo tutorial)
Post by: brelo on January 17, 2008, 01:06:49 PM
Thanks Josh, Excellent tutorial. Now I can’t wait for the painting tutorial.
Dave
Title: Re: Making a simple mold in silicone caulk (photo tutorial)
Post by: taxos on January 18, 2008, 04:03:37 AM
me too, can´t wait for the painting tutorial. I´ve got loads of stones awaiting!
Title: Re: Making a simple mold in silicone caulk (photo tutorial)
Post by: ladyarcher726 on March 04, 2008, 08:56:44 PM
I'm going to give this a bump for the new people (me included!).  Can't wait to learn how to paint rocks!  *bats eyelashes* 
Title: Re: Making a simple mold in silicone caulk (photo tutorial)
Post by: Bonnie ( Allistair ) on March 04, 2008, 09:48:21 PM
I gotta say, When I read this tutorial a few weeks back, I thought it was the greatest thing I had ever read.  I still think that!.  I LOVED silicone caulk as a mold making material, despite how long it took and how annoying it could be.. and this tutorial blew my mind...  Who would have thought a little dishsoap would do so damn much???  Freaking unbelievable.  Jknuth - THANK YOU!!!
-Bonnie
Title: Re: Making a simple mold in silicone caulk (photo tutorial)
Post by: Roger E on March 04, 2008, 11:20:43 PM
A little dish soap and a little paint...
Title: Re: Making a simple mold in silicone caulk (photo tutorial)
Post by: Bonnie ( Allistair ) on March 05, 2008, 12:15:54 AM
haha.. yeah... a little dish soap, and a little paint.  freakin amazing. :)
Title: Re: Making a simple mold in silicone caulk (photo tutorial)
Post by: 2wbdft on March 05, 2008, 07:30:15 AM
i agree.... along with molding a-bunch of rocks, i have now started to mold every different specie of bird that go's through my shop. what a $$ saver!

--thanks again for posting


Title: Re: Making a simple mold in silicone caulk (photo tutorial)
Post by: Pascal on March 05, 2008, 02:35:32 PM
I just got through molding a Bobcat Jaw set with this method and it worked out great. I was amazed how quickly the silicone sets up when you add the paint. Thanks again Josh.
Title: Re: Making a simple mold in silicone caulk (photo tutorial)
Post by: Jknuth on March 05, 2008, 05:08:58 PM
Yay
Cool beans.
I know this tip helped me a ton and it looks like its helping everyone else as well.

Post some pics people of your molds and castings, and throw them in the mold of the week thread. http://www.taxidermy.net/forum/index.php/topic,36548.0.html
Title: Re: Making a simple mold in silicone caulk (photo tutorial)
Post by: Steve Rotramel on March 07, 2008, 07:15:22 PM
Dude you are the man!  The only thing I found for smoothing the first coat was spit, which explains why I have to eat through a straw now.

And how many times have I waited (waited and waited) for those darn things to dry.  Way to go!
Title: Re: Making a simple mold in silicone caulk (photo tutorial)
Post by: RabbitHill on March 08, 2008, 02:05:11 PM
I just found this tutorial while browsing the site and wanted to thank you for sharing your knowledge.  ;D  I am a true beginner at taxidermy and treasure any tips and tricks that the pros can offer. Thanks again!
Title: Re: Making a Simple Rock Mold with Silicone Caulk
Post by: Craig W on May 12, 2008, 07:30:08 AM
Ive been messing with this since I found it and have had pretty good results.I was wanting a rock that would be good for small game pedestal mountsand for fish mount pedestals.I have finished that mold and have made some pretty good casts from it.Now I'm molding a kind of large rock for standing foxes,cats,etc...Ive done used up 13 tubes of silicone making it thicker and it looks like its going to come out good to.This will sure beat buying those rocks.I will post some pics soon.I have one of my competition fish sitting on one of these rocks and will post a pic after the show(its this week).
Thanks for this post.
Title: Re: Making a Simple Rock Mold with Silicone Caulk
Post by: Craig W on May 13, 2008, 05:55:34 PM
Here is a couple pics of what Ive been able to do with it since finding this post.The couple rocks(casts) are painted with grey primer so that maybe the detail would show a little better for the pics.I havent had time to paint them.
Title: Re: Making a Simple Rock Mold with Silicone Caulk
Post by: Craig W on May 13, 2008, 05:56:59 PM
Here is a smallmouth I'm working on.The rock its sitting on was made from one of these molds.
Title: Re: Making a Simple Rock Mold with Silicone Caulk
Post by: Craig W on May 13, 2008, 05:59:24 PM
Here is a pic of one of the molds.Thanks for the post jknuth
Title: Re: Making a Simple Rock Mold with Silicone Caulk
Post by: laserred on June 02, 2008, 10:25:03 PM
Mine turned out great!  The first castings stuck to the rock, so the next ones I sprayed the rocks with pam!  They just plopped right out of the mold!  Too bad my painting of them didn't go so well!   :-\ 
Title: Re: Making a Simple Rock Mold with Silicone Caulk
Post by: Amy on June 02, 2008, 10:38:20 PM
I posted these in the molding & casting category last week .. I followed this article exactly, and molded my first rock. They turned out great!! The dark rock is the original, the other two are castings, painted different ways

(http://www.amystaxidermy.com/rocks1.jpg)
Title: Re: Making a Simple Rock Mold with Silicone Caulk
Post by: boarhunter67 on June 04, 2008, 07:10:28 PM
Those look great.  What paints/methods did you use for each of the two (not counting the red, LOL)?
Title: Re: Making a Simple Rock Mold with Silicone Caulk
Post by: Amy on June 05, 2008, 11:54:32 AM
Thanks, I casted them using por-a-cast tinted grey for a base color. Then I airbrushed them with lifetone lacquers. Its easy to paint rocks because there's no real wrong way, you just dont want it to look all one color. I used greys, browns, and a little black. With the one on the left, I took it outside and covered it in dry dirt, then shook it off. Thats what gives it the dusty appearance. I also attached some small pieces of real moss to it. For the darker one on the right, I took a paintbrush and stippled white and tealish-green oil paint on it. It makes it look like it has lichen on it!
Title: Re: Making a Simple Rock Mold with Silicone Caulk
Post by: utsiishi on July 13, 2008, 08:35:49 AM
sweet
Title: Re: Making a Simple Rock Mold with Silicone Caulk
Post by: Gobblingfever on July 13, 2008, 10:28:35 AM
Are the molds filled completely with the resin,bondo, hardner mixture or just a thin layer all around? How are these being attached to the bottom of bases?  I have never built any of my own habitat.
Title: Re: Making a Simple Rock Mold with Silicone Caulk
Post by: Craig W on July 14, 2008, 07:32:44 AM
You can just make a shell.When you put the fiberglass resin/bondo in there,just keep moving the old around trying to let it run and over the whole inside until it sets.If you dont think its thick enough,do it again.For anchoring this you can take the rock after you make the shell and mix up a little more and set a wood block on the inside and pour more of the mixture around it.Good luck.
Title: Re: Making a Simple Rock Mold with Silicone Caulk
Post by: thatguyonline on October 14, 2008, 09:15:59 PM
So when are we going to see the tutorial on how to paint rocks?
Title: Re: Making a Simple Rock Mold with Silicone Caulk
Post by: newbietaxiderm on October 31, 2008, 10:53:02 AM
Im eager to see it as well :) This post is addicting
Title: Re: Making a Simple Rock Mold with Silicone Caulk
Post by: CHT on October 31, 2008, 11:06:54 AM
Looks great
Title: Re: Making a Simple Rock Mold with Silicone Caulk
Post by: thatguyonline on November 13, 2008, 03:03:41 PM
i have a tube of silicone that says, "100% Silicone filler for window, gutters,.................." Is this 100% silicone? I think should work. just checking

Thanks
Title: Re: Making a Simple Rock Mold with Silicone Caulk
Post by: Catchaser on November 24, 2008, 11:58:04 PM
This is great! Do you have a pic of the final cast??? Thanks for the tutorial.

Catchaser
Title: Re: Making a Simple Rock Mold with Silicone Caulk
Post by: RollaJedi on December 01, 2008, 04:19:06 PM
so, the only release agent you need to put on the master is a little bit of vaseline?? 

I really want to try this but want to find out what other people have used as their release agent. 
Title: Re: Making a Simple Rock Mold with Silicone Caulk
Post by: Justin S on December 03, 2008, 01:56:02 AM
This is a very informative thread, and helped me out quite a bit
Title: Re: Making a Simple Rock Mold with Silicone Caulk
Post by: kodeman on December 06, 2008, 12:52:39 PM
Great tutorial. Its very interesting!
I saw on here about someone using laquer thinner to thin bondo. Does any one know the thinner to bondo ratio?
If not, will fiberglass resin work to thin bondo enough to use for the mold?

Thanks
Kodeman
Title: Re: Making a Simple Rock Mold with Silicone Caulk
Post by: [email protected] on December 06, 2008, 01:29:32 PM
Kodeman...use resin
Title: Re: Making a Simple Rock Mold with Silicone Caulk
Post by: kodeman on December 06, 2008, 02:06:08 PM
Thanks!

Whats the ratio for it?
50/50? 60/40?

I think i'm going to try this tomorrow.


Kodeman
Title: Re: Making a Simple Rock Mold with Silicone Caulk
Post by: JL on December 06, 2008, 10:05:48 PM
Kodeman....Bondo is made up from fiberglass resin and a filler so any thinner that will thin resin can be used safely..that is lacquer thinner...Acetone. Acetone seems to be the best 'cause it evaporates quickly. Just use enough to get the Bondo to the pourable state you're looking for. If you want to thin with resin be sure you use "layup resin" as paint will stick to it while regular resin has a finishing wax that makes the surface smooth and slippery.Since you're not looking for strength, thinning shouldn't be a problem. If you want to strengthen a molded rock simply chop some fine fiberglass cloth into some thinned Bondo and line the inside of the molded rock with this mix and let it harden. Not rocket science. Great post and tutorial...5stars.  JL
Title: Re: Making a Simple Rock Mold with Silicone Caulk
Post by: kodeman on December 07, 2008, 01:52:35 PM
Thanks for your help. I was going to try this today but i cant find white bondo hardener any where. everyone just got the red hardener. Does any one know what stores carry this?

kodeman
Title: Re: Making a Simple Rock Mold with Silicone Caulk
Post by: [email protected] on December 07, 2008, 03:43:57 PM
The white hardener is available at WASCO. I have never seen it locally.
Title: Re: Making a Simple Rock Mold with Silicone Caulk
Post by: JL on December 07, 2008, 08:17:45 PM
Since the active ingredient in Bondo is RESIN....just use the same activator you use for the resin. Try a small sample and time the reaction time. Chances are the bondo activator is the same thing with a colored pigment so you can see even distribution. EXPERIMENT!!!!! Good luck...JL ::)
Title: Re: Making a Simple Rock Mold with Silicone Caulk
Post by: Jknuth on December 07, 2008, 10:44:24 PM
hey all

As far as thinning resin ive had nothing but bad luck thinning with solvents.
I thin the bondo putty buy adding polyester resin. 50/50
for hardener you can use just the cream hardener you use for bondo, but using the mekp hardener for polyester as well will add additional hardness to your casting.
For white hardener check some automotive stores, I mean real ones not the chains.
they should carry it for body work in a few colors.
white, blue, red, yellow

good luck
Title: Re: Making a Simple Rock Mold with Silicone Caulk
Post by: JL on December 08, 2008, 01:53:39 PM
Folks...we're making HOLLOW ROCKS here, not building a boat or covering one with fiberglass cloth. Strength is not the primary consideration, detail is, and these rocks probably should be filled with foam....the really cheap kind that you use to seal windows and door gaps. I agree that thinning with solvents will weaken the Bondo a little but not enough for this application. Thinning with resin is the best way but you can do it with lacquer thinner or acetone if you don't have resin in the shop and it will work well.I wouldn't use solvent to thin resin if I was laying up a reproduction fish in a mold though...but for rocks????????? Good luck...JL
Title: Re: Making a Simple Rock Mold with Silicone Caulk
Post by: Jknuth on December 09, 2008, 01:10:00 AM
Folks...we're making HOLLOW ROCKS here, not building a boat or covering one with fiberglass cloth. Strength is not the primary consideration, detail is, and these rocks probably should be filled with foam....the really cheap kind that you use to seal windows and door gaps. I agree that thinning with solvents will weaken the Bondo a little but not enough for this application. Thinning with resin is the best way but you can do it with lacquer thinner or acetone if you don't have resin in the shop and it will work well.I wouldn't use solvent to thin resin if I was laying up a reproduction fish in a mold though...but for rocks????????? Good luck...JL

Actually I disagree.
Thinning with solvents will soften the surface of the rock.
and when the rock is antiqued and buffed with steel wool it will remove and round the surface.
it also will effect how some paints respond to the resin.

as far as foam filling. yep not a bad Idea. I would use a two part urethane foam because the foam in a can will break down within a year or so and offer no support over time.
Title: Re: Making a Simple Rock Mold with Silicone Caulk
Post by: viper485 on February 09, 2009, 12:47:56 AM
Can't wait to try your mold/cast method of making rocks.  I have always made them the old fashioned,HEAVY way with wire mesh, burlap, and thin set mortar.   But I was wondering how you would go about attaching multiple rocks, in ledges for a mt. lion walking on a rock base for a pedestal mount?   Most of what we do is large animals, lots of pedestals.  If you or anyone else has any tips, I sure would appreciate the ideas.  Thanks again,  have certainly gone to school on the rocks here!  THANK YOU!!   
Title: Re: Making a Simple Rock Mold with Silicone Caulk
Post by: partsman on February 16, 2009, 08:20:38 PM
Hi Jk, I just joined this forum to let you know that your method has spread beyond the taxidermy world check out this thread here:
http://www.halloweenforum.com/general-halloween/75958-silicone-molds.html
I hope you like how your work is spreading ::)
Title: Re: Making a Simple Rock Mold with Silicone Caulk
Post by: sc09 on February 22, 2009, 01:01:33 AM
Ive read up on making molds from silicone caulk and they all say acrylic paint as an additive makes the silicone cure faster and more evenly throughout. I tried it with some cheap acrylic from Walmart and it hasn't set in two days and so I went to an art store and bought a more expensive acrylic and it still doesn't set at all as fast or as strong as just the silicone by itself.

I'm wondering what I'm doing wrong. Your molds come out really awesome (and your tutorial is awesome too by the way) but I feel like I'm just wasting money on paint. I'm using GE silicone II for doors and windows in a red bottle and the acrylics I've tried are from Apple Barrel and Amsterdam Standard Series.
Title: Re: Making a Simple Rock Mold with Silicone Caulk
Post by: Jknuth on February 22, 2009, 03:10:00 AM
Are you sure the caulk is 100% silicone? and not Siliconized?
Title: Re: Making a Simple Rock Mold with Silicone Caulk
Post by: sc09 on February 22, 2009, 06:33:12 AM
wow thanks for the quick response haha!

It says "100% silicone sealant" on the front. It also says BioSeal which apparently is mold and mildew protection, not sure if that makes a difference. Although, there was one post I read here that said something about not buying the blue one because it was "out of date" but it was all they had and it expires 02/10.

I tested the plain silicone and the silicone+acrylic side by side and the plain silicone set faster and a lot stronger than the silicone+acrylic. Even by the silicone had already set the silicone+acrylic was really sticky and little pieces of it would come off. hmm I don't know if its the silicone or the acrylic. . .thanks again for the quick response.
Title: Re: Making a Simple Rock Mold with Silicone Caulk
Post by: Jknuth on February 22, 2009, 01:17:28 PM
hmm
thats odd. it should kick in about 10 minutes and be ready to de mold in a half hour or so.

try a small test batch with a tiny amount of paint.
It doesnt need to be much at all, justa  little dab.

Its possible there is too much paint and you are not getting a good reaction.

Title: Re: Making a Simple Rock Mold with Silicone Caulk
Post by: ctf1800 on February 22, 2009, 03:08:50 PM
Just to add my 2cents, you can use an old dryer sheet on the last layer to give the mold some extra strength.
Title: Re: Making a Simple Rock Mold with Silicone Caulk
Post by: sc09 on February 22, 2009, 05:23:40 PM
That's a good idea, now that I think about it I may have put more paint then I needed because the ones I bought were a little more watery than what your pictures look like. I'll try less paint this time. I think I'll try the blue tube next time, I need some more silicone anyways. Thanks for all your help, ill let you know how it goes!

And the old dryer sheet is an awesome idea too! Ive been thinking about what I had around the house to use in the plaster that holds my mold in place. Old dryer sheets are a lot stronger than anything like tissues and they're porous, flexible and I definitely have enough of them. Good work!
Title: Re: Making a Simple Rock Mold with Silicone Caulk
Post by: ctf1800 on February 22, 2009, 06:13:35 PM
Just wanted to add this site: http://www.bragdonent.com/gfguide.htm, you can purchase rock molds allready ad and can purchase kits with the resin and foam I use this for my train hobby thought it might work here too.
Title: Re: Making a Simple Rock Mold with Silicone Caulk
Post by: Speckled Trout on February 24, 2009, 01:17:24 PM
Has anyone tried to cast something in cement?  Will it react with the silicone or try to stick?  Would you use a release? 
Title: Re: Making a Simple Rock Mold with Silicone Caulk
Post by: partsman on February 25, 2009, 12:41:44 PM
Spekled, over on the Halloween Forum, one of our members is currently in the process of casting a skull in cement, I'll try to find out what progress she's made and get back to you.
Title: Re: Making a Simple Rock Mold with Silicone Caulk
Post by: sc09 on March 05, 2009, 09:52:11 PM
So, earlier I had an issue trying to make the silicone to cure using the acrylic paint and I didn't know if it was the acrylic or the silicone that was the problem. I recently bought the red bottle, GE Silicone II-Kitchen and Bath (I was using the blue bottle, GE Silicone II-Doors and Windows) and tried mixing a little bit with the acrylic.

It still didn't set as fast as just the silicone alone and I thought it was working because it somewhat cured on the outside. I peeled it open a little bit and it was all gooey on the inside. I think the acrylic is probably the issue. I used two kind of runny type acrylic paints for this project and they didn't work out so I guess I'll try some of the thicker heavy bodied acrylic next.

As for now, Ive been completing the mold in thin layers of plain silicone and it actually works really well. If enough coats are applied, its really flexible yet firm and doesn't feel like it will tear. Just make sure you let the dish soap dry between coats or the layers might peel apart a little.
Title: Re: Making a Simple Rock Mold with Silicone Caulk
Post by: Rob43 on March 20, 2009, 12:53:57 PM
Awesome Post Josh!! I am going to give it a try. I need to make some rocks for an Otter scene.
Again, thanks for a very informative post!
Title: Re: Making a Simple Rock Mold with Silicone Caulk
Post by: ynotnow817 on May 05, 2009, 05:39:09 PM
I have made some excellent sillicone molds. I use Brick In The Yard Mold Supply. http://www.brickintheyard.com/ They are here in Texas and they have some great Youtube videos here.
http://www.youtube.com/bitymoldsupply
Title: Re: Making a Simple Rock Mold with Silicone Caulk
Post by: joeuhuh on June 04, 2009, 12:52:09 AM
simple querstion ihavnt seen asked yet when u coat rock with silicone what isit sitting on that its not sticking to (the white stuff i cant tell what it is)  cause was gona try this and wondered why ur siliconed rock wasnt sticking to the  thing it was sitting on

thanks joe

hehe i know it looks like a piece of styrofoam - i makein sure -- askin dum questions cant make u any dummer and it cant help ur spelling either
Title: Re: Making a Simple Rock Mold with Silicone Caulk
Post by: glarsonnd on June 06, 2009, 02:12:16 PM
I like to staple plastic to a board then set rock on,if rock is unlevel I will build up with clay. I made 12 rock molds and am putting a 4 ft rock border around my home it looks great using using cement and coloring with the camoflage spray on flat colors it looks great.
Title: Re: Making a Simple Rock Mold with Silicone Caulk
Post by: ynotnow817 on June 07, 2009, 12:57:24 AM
I like to staple plastic to a board then set rock on,if rock is unlevel I will build up with clay. I made 12 rock molds and am putting a 4 ft rock border around my home it looks great using using cement and coloring with the camoflage spray on flat colors it looks great.

Got any pics?
Title: Re: Making a Simple Rock Mold with Silicone Caulk
Post by: glarsonnd on June 07, 2009, 11:42:07 PM
I will get some it has been raining here for 2 days soon as it quits ill get some and show how I did this. Thanks
Title: Re: Making a Simple Rock Mold with Silicone Caulk
Post by: Joey Arender on July 16, 2009, 10:06:05 PM
I just did ten rocks like this thanks again saved me a bunch of gi1100   LOL
Title: Re: Making a Simple Rock Mold with Silicone Caulk
Post by: WolfMan96 on July 18, 2009, 12:50:40 PM
great tutorial,  I'm going to use this tutorial for years to come
Title: Re: Making a Simple Rock Mold with Silicone Caulk
Post by: Leslie J. on July 24, 2009, 06:49:19 PM
AWESOME tutorial!  I'm very excited to try it.  Thank you for taking the time to share this with us.  In the future will you be able to do the painting tutorial of this ??? ;)

~Leslie
Title: Re: Making a Simple Rock Mold with Silicone Caulk
Post by: Gobblingfever on July 24, 2009, 08:50:01 PM
AWESOME tutorial!  I'm very excited to try it.  Thank you for taking the time to share this with us.  In the future will you be able to do the painting tutorial of this ??? ;)

~Leslie
Yes that would be nice. Probably simple but I am one of those hand on gotta see it type myself not one of them book smarts.
Title: Re: Making a Simple Rock Mold with Silicone Caulk
Post by: Jknuth on July 25, 2009, 02:31:29 PM
AWESOME tutorial!  I'm very excited to try it.  Thank you for taking the time to share this with us.  In the future will you be able to do the painting tutorial of this ??? ;)

~Leslie

AWESOME tutorial!  I'm very excited to try it.  Thank you for taking the time to share this with us.  In the future will you be able to do the painting tutorial of this ??? ;)

~Leslie
Yes that would be nice. Probably simple but I am one of those hand on gotta see it type myself not one of them book smarts.


In the words of Wesley from princess bride......... "As you wish"

http://www.knuthart.com/joshua/blog/

;D
Title: Re: Making a Simple Rock Mold with Silicone Caulk
Post by: Gobblingfever on July 25, 2009, 06:01:47 PM
Paint type?
Title: Re: Making a Simple Rock Mold with Silicone Caulk
Post by: Jknuth on July 25, 2009, 06:28:43 PM
Acrylics

I use artists arcrylics, but any acrylic will do.
I even use the cheap walmart stuff
Title: Re: Making a Simple Rock Mold with Silicone Caulk
Post by: Outwoods Taxidermy on July 27, 2009, 01:36:51 PM
anyone try this method on antlers/horns...
Title: Re: Making a Simple Rock Mold with Silicone Caulk
Post by: [email protected] on July 27, 2009, 04:46:18 PM
Making a usable mother mold would be very difficult if not impossible.
Title: Re: Making a Simple Rock Mold with Silicone Caulk
Post by: Leslie J. on July 27, 2009, 07:23:29 PM
Thank you so very much, you are truly amazing (and have great music taste by the way)  LOL  Thanks again

~Leslie
Title: Re: Making a Simple Rock Mold with Silicone Caulk
Post by: GreenBullhead on August 07, 2009, 10:23:49 AM
I'll definitely be trying this out!!
Title: Re: Making a Simple Rock Mold with Silicone Caulk
Post by: Kenny on September 05, 2009, 11:41:58 AM
First time I ever tried to mold anything was yesterday.  I used this method and it worked great.  I found out a few things though.  My first attempt I used silicone II, either it was old or the number II doesn't work as well.  I could not get it to set up.  I headed to the store and bought GE silicone I. This stuff set up pretty quick which allowed me to get to the second coat within the hour.  I also found out it helps to coat your rock with vaseline first, to help release the silicone from the rock, as this attempt left a little bit of the silicone on the rock.  Third try everything came out great.  Thanks for the post!
Title: Re: Making a Simple Rock Mold with Silicone Caulk
Post by: jason74 on March 28, 2010, 04:49:34 PM
so do you fill the mold up or leave it hollow?
Title: Re: Making a Simple Rock Mold with Silicone Caulk
Post by: Chuck Holyk on March 29, 2010, 09:12:50 AM
Some leave it hollow, some fill it with foam.  I think its preference at that point.
Title: Re: Making a Simple Rock Mold with Silicone Caulk
Post by: Shadow_Wolf on April 28, 2010, 10:58:31 AM
Would you just leave the rock hallow if you were to make it into a key holder to hide a key outdoors?
Title: Re: Making a Simple Rock Mold with Silicone Caulk
Post by: duxrus on May 12, 2010, 11:27:01 AM
"Stupid" question on the painting of them......when you say (wash) how exactly are you doing a wash ? I assume you are thinning the paint but you know about assuming. ;D

Thanks
Title: Re: Making a Simple Rock Mold with Silicone Caulk
Post by: Scottio on May 18, 2010, 06:04:12 PM
  Hey Weasel,   I wish we all could be in the same shop teaching & learning how to mount differant animals and learn tips & tricks. Wouldn't that be cool! ...S
Title: Re: Making a Simple Rock Mold with Silicone Caulk
Post by: ColumbiaRiverTaxidermy on October 23, 2010, 02:27:22 PM
Making a usable mother mold would be very difficult if not impossible.

Why is that? with all the chemicals and materials out there?
Title: Re: Making a Simple Rock Mold with Silicone Caulk
Post by: [email protected] on October 23, 2010, 07:14:34 PM
Jay....piece of cake with the right materials but caulk in a tube is not the material.
Title: Re: Making a Simple Rock Mold with Silicone Caulk
Post by: boarhunter67 on October 24, 2010, 09:41:07 PM
Jay....piece of cake with the right materials but caulk in a tube is not the material.
I've used the silicone caulk from Home Depot for lots of molds from bison horns to pig teeth.  It works great if you thin it with Xylene and add acrylic paint as a catalyst.
Title: Re: Making a Simple Rock Mold with Silicone Caulk
Post by: [email protected] on October 25, 2010, 06:39:41 AM
Boarhunter....you be sure & post a picture of your first set of non-typical antlers done that way. LOL
Title: Re: Making a Simple Rock Mold with Silicone Caulk
Post by: boarhunter67 on October 25, 2010, 06:36:14 PM
Boarhunter....you be sure & post a picture of your first set of non-typical antlers done that way. LOL
  Antlers are another story.  I've never tried them.  I've seen many tutorials on how to replicate them, and every tutorial or article looks very tricky no matter what material is used.  I have had a lot of luck with bison horns, pig teeth and mouthsets, etc. using the tube silicone thinned with xylene and a bit of acrylic paint added, synlube as a releasing agent, and painting it on in layers over what I wanted to copy.  I've even done a couple of fish this way.  I've had great results.  With some of the larger molds like bass, I made a mother mold of plaster or rock hard to help the silicone hold the shape.  I've gotten amazing detail.  I'm sure the more expensive stuff is better, but for what I've done the tube stuff from Home Depot or Walmart has worked well.  The only thing I've had trouble with is thin stuff like fish fins.  I'm not sure if the more expensive stuff would work better or if my technique is just needing improvement.  If I was sure it wasn't my technique, I would invest in some of the expensive stuff because I hate spending so much time fixing my fins when I de-mold them. 
Title: Re: Making a Simple Rock Mold with Silicone Caulk
Post by: black wolf on October 29, 2010, 11:12:02 PM
wesel try to hard boil the egg first
Title: Re: Making a Simple Rock Mold with Silicone Caulk
Post by: black wolf on October 29, 2010, 11:17:04 PM
thanks for the tip, I am goint to try it this weekend on a log that I want to make up for a coon thanks again
Title: Re: Making a Simple Rock Mold with Silicone Caulk
Post by: mousesong on December 02, 2010, 10:26:39 AM
Hi all! Much as taxidermy fascinates me I don't think I ever foresaw that I'd be signing up for a forum :)

But this method has spread pretty far and you guys seem to be the most knowledgeable about it (and way nicer than most forums I've run across lately), and I had a few questions before I invested the time in using it.

I have some small mostly-columnar sculptures, about two inches high and about an inch across. They have some curves in them, a little less than the degree you'd see in a coke bottle. There is a fat part near the top and then a slightly thinner "neck" underneath. It's not a lot thinner--just very slightly dips in, as if it had been lightly compressed with a finger. My question is this:

If I mold them so that the base of the sculpture is the opening of the mold, would they successfully release from the mold? Is it flexible enough, or would the fattest parts get caught in the "neck" of the mold and refuse to release? It's hard for me to tell from the pictures etc. whether this mold would suit my purposes or if (sigh) I am going to have to make a two-piece mold and deal with the flashing and associated mess :) Grrr undercuts!

I need about... oh... fifty of them? From around five original sculpts. Would the mold hold up to that many casts--around ten per mold? I'll be casting in clear resin.

If worse comes to absolute worst, I can make the mold individually each time and break it for each cast, but I'll have to raise my end prices considerably and that's also kind of a pain :)

Thank you in advance for y'all's help!
Title: Re: Making a Simple Rock Mold with Silicone Caulk
Post by: kirby/575.693.6699 on April 16, 2011, 05:42:33 PM
marking
Title: Re: Making a Simple Rock Mold with Silicone Caulk
Post by: Old Fart on April 16, 2011, 09:12:54 PM
I don't know how I missed this thread before this. I've been making rock molds like these, both from the silicone and latex, for many years. A trick I learned from Jeff Compton, was to make a splash coat of plaster in the mold before the Bondo. This will give you a softer look to your finished rock, without a shine. Willis Houston(former owner of Dixiland Supply) made antler molds this way with a fabric reinforcement. He switched over to the catalized silicone, so apparently he found it less than satisfactory.
Title: Re: Making a Simple Rock Mold with Silicone Caulk
Post by: Susan M. on April 17, 2011, 08:10:39 PM
thanks for the tip, I am goint to try it this weekend on a log that I want to make up for a coon thanks again
Hope you post how this turned out!
Title: Re: Making a Simple Rock Mold with Silicone Caulk
Post by: madtrapper22 on April 25, 2011, 03:44:20 PM
All I can say is wow great post thanks for the lesson
Title: Re: Making a Simple Rock Mold with Silicone Caulk
Post by: boarhunter67 on April 26, 2011, 03:40:34 PM
Mousesong, it is somewhat flexable so it should release, but you might need to shoot some air into it to make sure it unmolds completely before peeling off.  If it doesn't, make a releaf cut and pin this shut when re-using.
Title: Re: Making a Simple Rock Mold with Silicone Caulk
Post by: FIELD2FOREVER on April 27, 2011, 03:24:47 PM
marking
Title: Re: Making a Simple Rock Mold with Silicone Caulk
Post by: doedumatch on July 20, 2011, 02:35:03 PM
*
Title: Re: Making a Simple Rock Mold with Silicone Caulk
Post by: Wyatt Oakley on September 18, 2012, 06:16:20 PM
I cast my first rock using this method!   I cannot believe the detail that the mold has.  I used the bondo and resin to make the rock and it turned out great!  Thanks for posting this valuable and cheap way of molding,  can't wait to try other things using this technique.

How can you waterproof  the rock for use in a live waterfall?
Title: Re: Making a Simple Rock Mold with Silicone Caulk
Post by: New York Rack Master 8 on April 18, 2013, 09:06:02 PM
The Greatest Thread about making rocks ever.  I will try this . this weekend and post when done.
Title: Re: Making a Simple Rock Mold with Silicone Caulk
Post by: Montgomery on April 20, 2013, 02:59:51 AM
This is something that could cause a problem down the road, as you will want to have control over your life and not let your games control you. Be aware of these addictive games and try not to fall into the trap of playing them for the majority of the day.
Title: Re: Making a Simple Rock Mold with Silicone Caulk
Post by: Dead water fish jaws on January 20, 2017, 05:36:11 PM
Did you ever doi the painting tutorial?
Title: Re: Making a Simple Rock Mold with Silicone Caulk
Post by: blklab on February 15, 2017, 02:35:22 PM
This tutorial is awesome ,   The only issue I had was mixing the "rondo" ....  I started using a combination of the Red Hardener and the clear Fiberglass resin Hardener into the 50/50 Bond Fiberglass resin mix....
To get it to finally kick , I hard to add more Red hardener to the mix.........  The result was great though...  thanks for the post.
Title: Re: Making a Simple Rock Mold with Silicone Caulk
Post by: crs on January 11, 2018, 10:42:02 PM
Great tutorial ! Thanks