Which clay do you guys use for contact with RTV silicone in the molding process?

I was doing a two-piece using Smooth-on Platinum cure thinking I'd be safe with a non-sulphur clay. The master was fine as was the mold-box, but got the gooey surface tackiness everywhere the clay and silicone met. I'll probably use wax in the interim, but was wondering which you use that works for you.

I didn't think I needed to cap or seal it, but it's been a while since I've made a mold...

Would mould-release or a thin film of Vaseline work to separate them? That way you could just use what you have instead of having to invest in a something like Klean Klay or Chavant.

Einion

Sorry Einion, but using any kind of greasy separating agent will not work. How would you smear Vaseline on the master anyway?

Haivng done a couple of bronzes, I can recommend Classic Clay which is a non-sulphur based clay. I prefer its texture to the Chavant as well. I hope this helps.

Mike

Clay/Silicone

Hi

I got some clay from Alumilite, that's made for cold-casting, and it works great. It cost me about $2.00 for a pd. I've also gotten it from a silicone supply house in the past. I use it all the time, no problems.

Regards

Bill

Thanks for the info guys, I'll grab some of the mentioned types.

Hi Mike, sorry, didn't remember this thread. Thought it was worth a shot if it would save buying new material.

This would be for the clay only, but if you had to you can brush it out thinly on the master with a soft brush; a friend used this as a release agent when doing some early casting in RTV and the results were fine. You can also thin Vaseline with mineral spirits if that would be necessary to prevent brushmarks.

Einion

Standard Sculpey (the pink one) and every kind of Fimo always worked well for me.

Thanks again. I put some Sculpey in some leftover RTV last night and it seems to have worked well so I'll try it with a master.

Just an FYI there is a mold spay you can get at places that sell casting stuff and what it is a sprayable petroleum jelly it works great and only puts light coating on the clay and parts. it is actually a great product. I used it a lot when I was doing model work for films.