I’m brand new here, and working on my first project… Unfortunately I went BIG.
I also made a mistake. I created an original sculpt out of plasticine. I decided to create the mold out of mold craft latex (which worked really well) and a mother mold on top of that from plaster.
What I didn’t realize is that I wanted to cast the piece in Flex Foam It III. Which apparently sticks to latex even when you use an insane amount of mold release. I now have to pick out the pieces of foam by hand before I can save the mold.
My question is, can you cast a layer of mold craft latex, in a latex mold and then I add the Flex Foam? I figure if flex foam bonds to latex so well, it will likely take the new layer of latex as a “skin” BUT what should I use as a release between the two layers of latex?
Hi there. Your sculpt looks good. I hope you can clean the mould u p alright to be able to use it again.
There are a couple of approaches to your problem, apart from the obvious taxi driver reply of 'I wouldn't choose to start from here!'. It depends on what you want your final piece to be made of. I am assuming you want a latex skin with flex foam inside it.
It might be possible to cast latex inside latex, although I think there are big risks of it all sticking together and making an unrescuable mess. To try out whether this might work, do a test with some latex and release agents, and then proceed very carefully.
Another approach might be to use the latex mould to cast a new clay sculpt, which you can then make a plaster mould from, this being the ideal material for casting liquid latex inside. You can warm Chavant clay until it is very soft, and then brush and press it into the mould, building up a good thickness. If you then put the mould halves together, you can pour a plaster block inside the clay. The detail may need quite a bit of cleaning up, but you effectively get your sculpt back. Then proceed to make a plaster (dental stone, Ultracal, Crystacal R NOT plaster of Paris) mould in as many parts as you need, and finally slush mould the latex inside and foam inside that.
The principle to always bear in mind is to cast something flexible inside something rigid and vice versa. Hope this helps.
Thank you for the reply!
I think I'll be doing a LOT or testing. I'll have to find some of the plaster you're talking about as all I have is plaster of paris, which is why I didn't use it as the main mould.
I'm wondering which of the two products below would be better as they are both available locally:
Or the Ultracal
Either way I'm going to have to modify the sculpt at some point.
This is a large piece, so I am wondering if the extra strength is worth the extra weight.
It looks like I have some experimenting to do!
The Ultracal is mould-making plaster and is the best for your purposes. Plaster of paris is too weak to give crisp fine detail. When you make a mould using Ultracal you can reinforce it with burlap or glass fibres, so it does not have to be too vast or thick. You do need to have 'keys' so the pieces fit perfectly together.
The Chavant clay is able to be melted with heat or in a microwave... carefully, and then used with great care so as not to get scalding hot sticky clay on your hands. It cools quite fast. Comes in soft, medium and hard.