Salt in plaster molds.

[kidlizard]

I heard somwhere that adding salt to plaster helps make it stronger and remove air bubbles. So I tried it out. Well I think I added too much salt (2 cups salt per 10 cups plaster). The results appeared great at first, but when I cut my molds apart ( i pour 4 or more molds in one big flat pan at a time then cut) the plaster was not cured all the way through and the molds crumbled very easily. I always lay the plaster on a heater for a few hours to speed the curing, but I guess I didnt allow enough time. Maybe I added too much salt.... Does anyone know what I did wrong? Thanks.....John Huffman

[alsworms]

Hi John,

I've never heard of the salt idea with plaster molds, but I can tell you what I've learned about stopping bubbles. If you haven't already tried this, add your water into the plaster instead of vice-versa. I read this once somewhere and I'll be darned if it doesn't work!! I think it just mixes better and keeps those tiny holes to a minimum. Hope that helps

Chris

[Senkosam]

Try tapping the bottom of the plater container on a flat surface to bring bubbles to the surface and then move them to the side with a flat object (spatula). Learned this in arts & crafts years ago.

[southstatesfishin]

AIRRID is a product that I found and have used for the last 20 molds I have made and the thing is ,it realy works!! Find it at hobby lobby or micheals in the plaster section. also if you want the best plaster to use it would be craft and hobby molding plaster of paris this stuff comes in a 8lb plastic jar not some card board box or DAP container with a bucket lid. This is found at one of the two stores mentioned above also. Get some and get pouring!!!