bondo help please

[mark c]

if i make a rock out of bondo        how do i get the texture to stick im trying to get a sand rock look  can i mix sand in with the bondo and then pour the mold ?    any help  thanks   mark c

[George Roof]

Not the way I make rocks, but try this.  Carve a piece of foam into the shape you like and then cover it with a coat of Bondo.  As soon as it's covered, sprinkle sand over it heavily.  The sand that actually sticks in the Bondo will stay there while any excess will simply fall off when you shake your rock after the Bondo dries.

[mark c]

good deal thanks   george ill get it go  mark c

[Dean]

A better way yet is to pour foam into large plastic bags or carve any open cell foam.  Peel the plastic off and carve the shape you want for a rock. I use a 2 lb foam. The cells are bigger witha 2 lb over a 3 lb. foam.  The different pours  can be bonded together for better shape and bigger rocks.   I then mix bondo and fiberglass resin to the consistency of syrup. Don't mix it very hot. You can purchase white hardener so you get a  gray rock. base color.  Use cheap paint brushes and brush it onto the foam. I can do about a 3' to 5' square area in one mix. The bondo resin mix will soak down into the foam cells  leaving you a nice 1/8" or so thick shell over the foam. It has a real nice rough rocky texture to it and strong enough to walk on.  Paint with a darker base coat then add different lighter colors and  washes  over that and sponge other colors to the desired look. It takes a little practice to get good color results but it looks great. I use the same process in making large trees, stumps, large mammal bases etc. I've been using this process for about 7 years now, and won 7 best habitat awards with the method.   

Another way is to make a rubber molds of a rock. Thin some bond as mentioned above, only a hotter mix. spray mold release onto the rubber mold. Pour bondo mix into mold and tip it around until it coats the entire mold with bondo. After it kicks and hardens you can add some wood to the inside  to attach the mount to. Pour foam on top of the bondo and let it expand and set up. Remove rubber mold and wipe off rock with thinner to remove mold release. Paint in a similar way as mentioned above. It gives you  natural looking rocks that can be made over and over.  By squezzing the mold a little while bondo is setting up can also give you different looking rocks out of the same mold.  I hope you undersatnd my explanation. Good luck

[mark c]

Dean thank very much that is exactly the answer i was looking for . I'm trying to get to the point where i can make commercial habat for the mounts i will be doing in the near future      i wanted a way to set the mount that wouldn't cost a lot look good and there friends would like . there is nothing worse than killing your self to produce a great mount and then just hand it to them ... i like the trash bag thing also i will be trying that also   again thanks mark c

[George Roof]

Mark, that wasn't an option posed in your original question and I simply answered the Bondo portion.  For a rock with a base, the new Rock Mix from McKenzie is hard to beat.  In the WASCO super seminar, dozens of "rocks" were built and made with it.  The "loose rocks" were made by dipping carved foam blocks into a mix is thn Plaster of Paris. When cured, they were then covered with Rock Mix.  To make smaller rocks, I simply paint a real rock with RTV.  Remove the mold when it hardens, paint the inside with Bondo as described and then pour foam inside.  Once it's cured, I put a block of wood inside the foam for  a mounting fixture and a place to secure to a finished plaque.   I've seen Jean Lavalee take papier mache and roll it into shapes with his hands and then sprinkle dry tempera paint on them for coloring.  He makes a superb "stream bed" with this multicolored "rocks".  As I said, Bondo isn't one of my favorite mediums for rocks.

[mark c]

George i hear you loud and clear im just trying to get a handle on this i did order the mc kenize rock mix and from the two responces ive gotten im learnung fast   thank you for your help mark c

[K Kave]

I didn't buy the rock mix just used base coat plaster from 84 lumber and mixed with blow in insulation worked the same can make 50 lbs for about 20.00 no shipping.

[Lisa M]

Mark...jknuth did a really fantastic tutorial on making a silicone mold.  If you do that, you can make the same rock over & over & over...getting the texture right in all of them.  Here's the link.  http://www.taxidermy.net/forum/index.php/topic,39157.0.html  Good luck!

[mark c]

Lisa M    I did see that and its a good one to watch   im just trying to get it altoghter   George also gave me some good ideas along with Dean and im going to go to lowes this weekend shopping for other things like morter mix coloring and what ever else i can dig up     shipping is a high cost for the begainner to bare    thanks mark c