Hey there quick question for you as you seem to know about the properties of the clay Im wanting to sculpt A mortal kombat mask out of clay whilst building the mask onto A polystyrene head..what clay would be the best and would the clay set solid or would I need to apply something to the clay like resin?? also how easy would it be to remove the clay from the foam head? much thanks if replied to : )
Which mask do u plan to build? With WED it's easier to build up thick pieces fast. WED clay is not exactly the same as the regular hobby clay from which folks make stuff like small ash trays, cans or whatever (which is then put in a clay oven).
WED has a substance in it which stops the clay from drying out too fast. This way you can leave your sculpt under a plastic bag for a few hours without having the piece become dry and brittle.
When regular hobby clay dries out it also shrinks - not noticeably but it does!
If you use a polystyrene head I would do it this way:
Mount the head on something steady or use a lazy susan if you have one (just more comfy t o work). Sculpt your helmet in WED clay. This way u would have two benefits by choosing WED:
1: u can build up large forms more quickly
2: it can be manipulated much quicker and easier than the oil based clays
If you have your sculpt finished - seal it with some light coats of clear (any ordinary clear out of a spraycan works!)
This way the water in the clay is encapsulated beneath the clear coat which stops the water from evaporating so the stuff doesn't begin to crack or shrink fast that much.
Also, the clear coat acts as a sealer. When it comes to molding the stuff you can use any medium you want...except resins since they do not want moisture or water.
I think making a two piece plaster mold would do the job.