Homemade Reusable Mold Material
I tried this mold material from a listed website, eventually making changes & making discoveries. This stuff is pretty good, although it is sensitive to heat. I haven't tried it for plaster or concrete yet, so please consider it as experimental.
The mold material feels like a very dense, foamy latex, flexible, but quite sturdy. I tried to tear a simple mold and couldn't do it.
If you're going to start mixing this stuff, do it when you won't have any interruptions & aren't hung over or operating on lack of sleep. Don't get sidetracked or you will regret it. (Ask me how I know....)
And don't try to rush things and add all the ingredients at once, or add them in another order. I paid $16 for a gallon of glycerin through my vet & wasted quite a bit.
!!!DENATURED ALCOHOL IS EXPLOSIVE!!! DO NOT ADD WHILE ON THE STOVE. DO NOT SMOKE WHILE USING. It is available from your hardware store. It is NOT rubbing alcohol. IT IS EXPLOSIVE!!!
I have only used silicone mold release on it, so far.
RECIPE for large batch (small experimental batch at end of post)
4 1/2 pounds dry Gelatin (my source says use flake gelatin, but I couldn't find any, so I used regular unflavored gelatin from a health food store.)
9 cups of cool Water (2.25 qts.)
13 cups Glycerin (3.25 qts or 9 lbs)
1 oz. Denatured Alcohol
Put the measured glycerin into a pot over LOW heat & start it heating. You do NOT add it to the gelatin unheated.
Pour the water into a large cooking pot & add the gelatin. Start mixing immediately & keep mixing until all the water & the gelatin is thouroughly mixed together (I used my hands). DON'T STOP mixing or it will separate & congeal in layers. When ready, the mess should be consistent in quality.
Place the pot over LOW heat & start stirring when it begins to melt, and keep stirring until the gelatin is all melted and free from lumps. Then add the heated glycerin and stir until blended. Continue to stir until all ingredients are thoroughly incorporated and REMOVE FROM STOVE ENTIRELY. Now add the alcohol and stir until thoroughly blended with the rest of the mixture. It is now ready to use, & should be used while warm.
Cooling the new mold can be accelerated by placing in the refrigerator.
When buying gelatin, be sure to SMELL it -- if it doesn't smell like JELLO, it isn't gelatin! A health food store sold me CORNSTARCH as gelatin, so beware.
I would tend to use dedicated utensils for this project.
The original recipe said to cook in a double boiler, but I didn't have one large enough, & didn't want to mess with 2 pots with rocks or marbles between, & just kept the temp on the lowest temp of my electric stove. It also said to include a pound of glucose, but I made mine without it, since I couldn't find any. Yes, glucose is a form of sugar, but since it didn't SAY to use sugar, I didn't. I suspect it was added to increase bulk, but I don't know for sure, & it works well without it.
To make into another mold, just put back in the pot and heat at LOW temperature. DO NOT add water.
This material can be used many times. If it starts getting debris in it, just form a sieve made from wire window screening in a funnel shape and while the material is melted, pour it through into another container.
(1/3 sized recipe for trial)
1.5 lbs gelatin
3 cups cool water
4 1/3 cups glycerin
1 Tablespoon denatured alcohol