I know this question has been asked many times but for some reason I don't remember a straight answer. What's the best way to store a silicone mold? I've been told to put a thin layer of plaster into it to keep it's shape, and I've also been told not to do this. Can you guys tell me how you store your silicone molds so they won't warp! Thanks in advance.
Most silicone molds do not store well for long periods of time. They do not tend to warp, but rather become brittle and easily torn. i always recommend storing a silicone mold with a full plaster casting in it, not a thin coat, and try to make it the best casting you can.
In this way- if you find the mold has expired, you will still have a good master from which to pull a new mold. Because plaster expands when it sets, you will have the smallest generational loss. Christopher
[Silicone rubber molds should be stored with a 'holding' piece inside, either plaster, or wax- or whatever you customarily use. This will keep them from sagging and losing their shape. Don't try this with urethane rubber molds, however, since the stuff will gradually adhere more and more to the casting, until they form a solid lump. Perhaps newer formulations of urethane are better in this regard; I'm not sure- I don't use it much myself.]
The best way I know is to make a wax pattern in the normal way (fill up the mold with liquid wax, wait 50 seconds and pour out) and leave it in the mold. There will probably be a tiny ammount of shrinkage, but nothing to worry about. I have also heard that its a bad idea to seal up the mold (with plastic?) as the fumes given off by the silicone will eventually cause the material itself to age prematurely. Keep it open but not totally exposed if you know what I mean.
Hope this helps
James Berrangé, Cape Town
it they are tin (condensation) silicone molds, you can place the molds in a plastic bag to retain their moisture so they stay pliable. a light coating of talc may help too.
platinum (addition) silicone molds do not exude any by products so they may be left out w/out any deterioration for many years.