Cheap Casting Resin? ($10-$20GAL)

Submitted by Unknown on 05/09/2004 at 14:07. ( )

Can anyone recommend an inexpensive pourable resin? My local hardware store has "fiberglass resin" for $20 a gallon. Would this be suitable for casting? Walmart sells 3 different types of Bondo. I have used "Auto Body" version for foam sculpture, mothermolds and other projects, but it's too thick for casting. What should I use?

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Depends what you're casting

This response submitted by Raven on 05/09/2004 at 14:26. ( )

If you want to do cheap little sculptures then yes you can use polyester resin (aka - fiberglassing resin). Be prepared because if you have any real thickness to it - it can very easily crack while curing from the extra heat generated. I can easily cast deer antlers with polyester resin for example since they are long and thin and dissipate heat readily.. but deer skulls if I were to cast them in poly res woudl crack. This cracking isn't necessarily a bad thing - just fill the cracks in with 2 part epoxy putty and carry on with your project.

For optimum casting ability - go with one of the many casting urethanes available. They ahve their own quirks about them - but by and large they are more suited to casting. To get the price of these down to a more feasible level, try adding one of the many fillers available for them from micro-spheres to talc.

Hope that helps =)

Resin venders

This response submitted by Rod Rock on 05/09/2004 at 14:27. ( )

Your best bet is to start with the resin Co like Cook,Ashland,AOC and resin supplyers like Fibergast .All have polyester casting resins.There are also casting list's on the web (there is a few that were posted a few months ago here) that would be able to help.
My self I would start with the guys that make the stuff first.
Rod Rock

Fiberglass Resin

This response submitted by Unknown on 05/09/2004 at 15:24. ( )

Thanks for the information y'all. Yes, I'm interested in some type of polyester... cheap, pourable and cures fast (15-60min) in a 1"-3" layer. I think I'll try the "fiberglass resin" at hardware store. Small sculptures I will cast solid, and big sculptures (ex, lifesize dolphin) will be hollow cast with fiberglass matte ("lay-up technique" inside mold interior). I thought I'd ask you guys before wasting $100s experimenting.

I haven't had much luck with urethanes... 1. Very sensitive. 2. Expensive compared to polyester. 3. Most of them do not cure properly without special machinery... degassing machine or rotocaster. 4. Not available locally, so I have to pay delivery. That's an additional $10-$20 per GAL! 5. Sticky! It destroys everything it touches. 6. After opening the container, you have to use the remaining immediately. So, I can't just buy 5GAL, use a little then store it. I know all urethanes are different, but generally, these statements are true about all the urethanes I've used (smooth-on). I can't afford the good ones from industrialpolymers or the non-toxic model type.

One more thing...

This response submitted by Unknown on 05/09/2004 at 16:00. ( )

Sorry if it sounds like I'm being cheap, but it is very important that I use the cheapest and fastest possible materials. Let me give you an example...

Let's say I'm creating a lifesize horse. It will cost $1.5K in foam, drywall putty and bondo, and take about 160 hours (1 month). Assuming I deserve to paid as much as an average plumber ($60 an hour) -- for providing a professional service that no one else in town does -- I would have to charge $11.1K ($9.6K + $1.5K for materials). No customer will pay that much! They can buy a real horse cheaper than that :) Even so, I wouldn't make $9.6K profit.
After paying 40% business tax and 50% to my salesperson, my actual profit will be $2,880. And after my monthly bills, there's practically nothing left. So, I'm considering molding and fiberglass techniques.

Anyone know where I can get silicone caulk in big quantities? 10.1OZ tube doesn't go very far. Thanks again.

You know...

This response submitted by marty on 05/09/2004 at 18:01. ( ) can thin bondo with fiberglass resin. Just make sure you use the appropriate amount of hardeners for each. And, adding some chopped fiberglass (or mat) will reinforce this mixture as well...

Good Idea...

This response submitted by Unknown on 05/09/2004 at 23:46. ( )

Thanks marty, I will definitely try that technique. It will save money for big projects. Bondo ($10/GAL) is 1/2th the price of "fiberglass resin" ($20/GAL).

Good Molding Book

This response submitted by rich on 05/10/2004 at 12:40. ( )

Hey, check the archives out here and you'll get all the answers. I started with Jim Halls Commerical Fish in Fiberglass book, then Ralph Morrills Museum Quality Fish Tax and have so much info. I'm building a boat with foam sheeting and fiberglass resin, thats just some of the info you can get. The resin you're talking about will work fine. Later, gone fishing.

Forget bondo

This response submitted by Raven on 05/10/2004 at 15:49. ( )

Bondo is simply the same resin filled with talc to make a paste. You can buy 50 lb bags of talc for 15 dollars US and make your own pastes of various viscosities and save even more money in the process. The main disadvantage to using resin filled with talc is how soft the surface is. It's easy to sand but can ding easily too. If you want a harder surface, fill your resin with fumed silica like Cab-O-Sil. Of course buying the right material from teh get go from aplastics supplier is your BEST bet. You can get a 5 gallon pail of gel-coat for $140 Canadian and a 5 gallon pail of resin for $110 Canadian!


This response submitted by Brett-n-Miami on 05/11/2004 at 00:44. ( )

You mentioned you wanted a fast cure, 15-60min. Polyester resins will GEL in less than an hour, but will need 4 hous before you can DEMOLD.

Your 3" layer will need to be poured in several layers. As Raven mentioned, it will crack if you poor it too thick. It will take longer to repair it than it did to cast.

To reduce your resin consuption, consider fillers that EXTEND your resin, not ABSORB it. Talc will act like a sponge and soak up your resin. Glass bubbles or microballons are like adding golf balls to a bucket of water. They raise the level, or extend, the water. Good luck.

another question

This response submitted by randall on 06/25/2004 at 20:07. ( rand1555@whudbey,net )

I'm trying to mold sculptures in a material that can be carved and sanded after casting. I've seen a lot of small art objects that are cast and look like wood but obviously aren't. They're designed for sale to hobbyists to finish and paint. Any ideas? I might have sections i" thick. Is polyester and talcum the way to go? Price is important but not critical.

fiberglass resin

This response submitted by Randalf Verad on 8/1/04 at 2:11 PM. ( )

A question. What is a good fiberglass resin to use on the fiberglass that is not to expensive that will deliver a good end result? I do not know much and would like to know the best value for it's price.

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