Mold Making on a budget

trekman1017

Well-Known Member
I would like to make some molds, but have a VERY limited budget. I always looking for cheaper ways to do things. I found this article on making a mold with Jello and was wondering if it could be used for a fiberglass casting. I would also like to know what else I could use for a mold like maybe clay? Mold Making with Jello
 

robn1

Master Member
Jello is a new one, never heard of that before.

If your master has a smooth surface and no undercuts, you can make a cheap mold with plaster. And if it has details and undercuts, use a thin layer of silicone rubber and back it up with plaster. Silicone isn't too expensive in small amounts, you can even get a trial size.
 

BrundelFly

Sr Member
RPF PREMIUM MEMBER
Im all about doing it cheaper.

However, there is a line of diminishing returns that once crossed, makes ya ask....WHY BOTHER?

There is a saying, "never enough time to do it right, but always enough time to do it over"

Good luck, and let us know what you manage.
 

PepMaster

Sr Member
Yes you can user silicone caulk but it's best if it's clear, and 100% silicone. You have to put it on in very thin layers, among other things you have to do to make sure it works right, heck I've used the RTV Red silicone you can get from Auto repair places, it sticks to high heavens but it works.
 

CB2001

Master Member
I actually heard if you mixed Mineral Spirits with 100% Silicone, you actually make it more liquid-like enough to pour your mold. I don't know if that's true or not, but the big thing that'd worry me is that Mineral Spirits is used to strip and dissolve paints (unless I'm incorrect about it), so I'd be worried about trying to make a mold of something and it strip the paint off an item.
 

PepMaster

Sr Member
You can do it with mineral spirits but it will extremely weaken the mold, it thins out the silicone to make it easy to pour but when the spirits evaporate you're left with the silicone it takes forever to cure no matter what.
 

CB2001

Master Member
You can do it with mineral spirits but it will extremely weaken the mold, it thins out the silicone to make it easy to pour but when the spirits evaporate you're left with the silicone it takes forever to cure no matter what.
I figured there was some sort of downside to using mineral spirits. I thought it would have been the risk of it destroying any paint on an object if you're pulling it. I bet using paint thinner would also result in the same kind of problem with the thinner evaporating and leaving the mold weak, or stripping paint of an item.
 
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