mould for a monster clay sculpt

[toxicvenom]

I want to make a mould to cast a silicone pull from a sculpt made with monster clay, my
question is what material to use as my concern is melting the sculpt if I use something
that gets hot as it cures like fibreglass or epoxy....

 

[pitchforknumb]

I've used fiberglass to mold on top of Monster Makers clay. Didn't have any problems. I usually do a very thin top coat, that way there won't be any issues with heat.

 

[Cyberman]

You can use Platinum cure Silicone rubber moulds to cast platinum silicone rubber pieces. But you always need to use release sprays to aid in seperation. The advantages of using a silicone mould is it gives you the choice of casting in resin or silicone. Also the heat generated by curing fibreglass moulds can melt wax based sculptures.

 

[Mr Mold Maker]

I have never had a fiberglass or epoxy mold melt clay. You're putting on maybe 1/16 of an inch total... spread that thin, fiberglass and epoxies barely gives off any real exotherm.



You have to remember that stone molds go through an exotherming process as well. If you've mixed your stone correctly it will actually steam. I've clocked it at over 200 degrees F with a hand held thermometer and that has never melted clay either. I have never had a glass mold get anywhere near as hot as a stone mold.

 

[Cyberman]

Coming from an experienced mold maker knowing exactly the amount of cat to put into the mixture at the given ambient temperature, that's fine... but if I was an inexperienced mold maker I'd not want to gamble on the cure not working right. Plat Silicone is the safest bet

I've had monster clay melt in sunlight so don't know where you're getting 200 F won't affect this medium

 

[Mr Mold Maker]

Plat Silicone is the safest bet

I've had monster clay melt in sunlight so don't know where you're getting 200 F won't affect this medium

I agree, platsil would be a lot easier for inexperienced mold makers... It certainly isn't a reason to avoid fiberglass.



You want to know something funny? The stone mold I clocked at 200? It was molding a Monster Clay sculpture. No melting of the clay.. Captured perfect detail.

I'd assume that it has something to do with properly sealing and releasing more so than the temperature.. but who knows.