air drying or non drying. Rock & a hard place

Hello Folks,

Ive got a dilemna thats been driving me nuts. I want to transform an object using clay, then make a mold of it to cast in resin. The problem I have is in choosing between two precarious routes: 1) I build on the initial object using a non-drying clay so that I can get good adhesion without cracking or shrinking. (I also foresee this as providing a more seamless addition to the initial object ) but the downside is that I wont be able to brush on silicon without affecting the clay underneath. Alternatively I go for 2) Use an air-hardening clay so that I can brush silicon on without fear of damaging or distorting the clay but will it shrink, crack and make joins between clay/object visible.

Thanks for listening.

You sure got a problem there.

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Hell, there are no rules here - we're trying to accomplish something.

Opportunity is missed by most people because it is dressed in overalls and looks like work.

Thomas A. Edison

At school we use "giotto pongo" for modelling with clay. Its some sort of hard clay that is usable when heated. You dont need to add any water with it. Have you tried these kind of clay?

And what do you mean with "affecting the clay underneath"? That it begins to transform?

Cheers Hombre Seeker,

Ill look into giotto pongo ( great name ) What I mean by affecting the clay underneath is distorting the soft sculpted form by dragging a brush loaded with silicon across it. If the object is rigid, of course this doesnt happen but i doubt that a drying clay would maintain seamless contact with the object ( Its a plastic plug btw )

Appreciate your input.

Alex

Could you use something like car body filler instead of clay?