Long term storage of mixed RTV silicone.

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Galane

New Member
If you have too much RTV silicone mixed for the mold you are making, don't let it go to waste setting up in the bucket or pour it on extra thick. Put it in a freezer. The cold temperature slows the chemical reaction way down, without turning the rubber into a solid.

I cast half a mold a couple of days ago with some Silicones Inc. P60 that was in my freezer for a month. I pressure cast it, which I do with all my silicone molds. I didn't intend to leave it in there so long, but I forgot about it. I was happy when the bit left in the bucket cured, would have been a sticky mess to clean up had it not.

I'd froze some once before but only for a couple of days. I got the tip from one of Silicones Inc's dealers, whom I buy it from. He said he'd froze RTV for up to two weeks.

Now I'm thinking I could nearly eliminate RTV waste by keeping a small bucket or two in the freezer to dump excess in then periodically use what's in the bucket instead of starting (or finishing) with a fresh mix.

I don't know if or how well this will work with tin cure because I only use platinum cure RTV. It would be interesting to see how long mixed RTV can be stored frozen before it either cures in the cold or won't cure after warming up.
 

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Galane

New Member
Yes. If you've overestimated how much RTV you need, put the excess mixed silicone in your freezer. One of the Silicones Inc. distributors told me he'd done that for up to two weeks. When I posted this I'd forgotten about some P60 I'd put in the freezer a month earlier.

It won't freeze solid but it will be pretty thick. Seems to pick up the curing where it left off when it warms up to room temp. For the mold I made I pressure cast it. I pressure cast all my RTV, and the resin castings in the molds. Bubbles? What bubbles?

Edit: Note that I have only put Silicones Inc. P60 in my freezer. I do not know how well or IF freezing any other silicone will halt or drastically slow down its curing!
 

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