Need advice on casting materials for a lifecast bust.

Hello!

I am hoping to do a lifecast in the next few weeks. I've been doing a lot of research, watching lots of videos, reading, etc... I'm going to be using the bust as an armature for sculpting masks. Once I'm done sculpting in clay, I'll take another mold of the completed project to cast in silicone.

One thing is that there is a lot of information out there on how to make the lifecast mold itself...but not a lot of information on the materials to use to cast the mold once it is created.

I was thinking of using silicone for the lifecast mold, but changed my mind to alginate. My reasoning was that once I make a permanent lifecast bust, I probably won't need to pull another bust of myself.

I am looking for a hard bust cast and weight isn't a consideration. I don't mind if the bust weighs 50lbs after I am done, as long as it is durable. I'm hoping to use/reuse this bust for years of sculpting.

And advice would be greatly appreciated.

Most are cast out of plaster of some sort. I taught lifecasting for foam appliances, and we used ultracal. Ultracal is a very hard plaster/stone, that self-adheres (within reason), and has very little warping/shrinkage. For mask sculpting, I have a bust made out of rigid polyurethane foam. This is great, because it is lightweight. If you intend to make masks out of latex, either of these methods will work. If you intend to make the masks out of silicone, you might want to consult with your material supplier. Platinum silicone (which is typically used for wearable masks) if FINICKY. Certain materials impede curing.

Thank you for your response.

Any thoughts on LiquiStone Gypsum Cement from Accu-Cast?