Slip Casting troubles

[nkoud005]

I am working on a sculpture using a slip cast but am running into technical problems. I have my plaster mold already, but it has some deep crevices in it so when I try to do the slip cast, it does not release from that portion of the mold. Does anyone know any tricks to help release the cast from the mold? If I put something like vaseline on the plaster, doesn't that defeat the purpose of the plaster pulling the moisture from the slip? Any ideas of how I could solve this problem would be great- this is my first slip cast project - I should have started with something simpler!! This is a one-part mold as well.

[Andy Clift]

You can use talc or or baby powder spread evenly on the mold before you pour it. To do that you can place the baby powder in a nylon sock, and softly dab it on the mold. Then close the mold and pour it. If they are bad undercuts you may have to carve them out of the mold, making your casted object more flawed but you could spend a bit more time clean up each piece. Also try letting the piece set more before you pull it.

How big is it and how long are you waiting now?

[nkoud005]

I will give that a shot. It's about one foot by eight inches. My first cast (only have done one attempt) I waited 30 minutes. It was too thin. Thank you

[Andy Clift]

Yes a lot of times it might take you several attempts to get the right thickness and hardness. With more experience it will get easier and you will be able to judge it better.