[brirye]

Hey all,

I'm trying to figure out a relatively fast setting mixture (overnight is ok) that I can pour into a mold for casting of breakable targets. I have a half torso body mold created using liquid latex and fiberglass. By half I mean the front/chest/face was modeled, and the back is open/exposed. I'd like to be able to mix something in buckets and pour it into the mold, let it sit, then remove it from the mold.

Requirements are: cheap, easy to find materials, able to mix in liquid form for pouring, needs to set in a day or 2, needs to have a reactive destruction property as we will be shooting at these and we want to visually be able to see the impact. Environmentally safe is preferred.

Here are a few things I have thought of, hopefully this gives you an idea of what I'm trying to achieve:

Basic play-dough allowed to harden (flour, salt, water) - Pros: cheap, easy to find materials, environmentally safe. Cons: Does not mix into liquid that can be poured, requires kneading.

Homemade chalk mixture (plaster of paris, water) - I tried this on a small scale, and I found that the mixture hardened too quickly into a paste. I could have been doing it wrong though. This was the mixture I thought would work best. Maybe I need to change the formula?

Gelatin mix (knox gelatin, water) - Would mix into liquid maxing pouring easy - requires refrigeration though, as the gelatin will rot - potentially expensive to buy lots of gelatin mix?

Expanding foam - would mix 2 parts into liquid, would set quickly - however it wouldn't be very reactive or destroy. would be hard to see bullet impact.

If it helps - I will probably only be using this mixture for a base layer. I was thinking of using something else as a filler between the front (chest) and back area. Example; lay mold down on chest so the open back is exposed. Pour in mixture. When mixture starts to set, add filler (paper, cardboard, cloth, whatever) - Cap off the back with more mixture.

Any advice appreciated!

[billnotgatez]

Had your mold been plaster, I would have suggested clay slip casting.
For what you are doing you probably do not need to fire the clay target.

You could use your current mold to make a positive plaster figure then use that positive to make a negative plaster mold.

Otherwise you might experiment with plaster mixtures to try and get a good plaster target.

[fledarmus]

You might try the expanding foam cast, then dip it into ceramic slip and allow it to harden. As billnotgatez says, you probably don't need to fire it. If you spray the foam cast bright orange before coating it with slip, you will end up with a whitish-grey target that when you hit it with a bullet, smashes over a large area to reveal a bright orange subsurface.