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Silicon drying up


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 My silicon has dryed up ? I store it upstairs in my house around 15-20 degrees celsius and I dryed out in under 6 months. Whenever I used it I was careful not to mix the two parts. Is there a way to make it last longer? Part a is solid and part b looks separated, I think part b can be mixed together though.

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Many chemicals have a finite shelf-life, and even some materials that require a second component or catalyst will go hard over time, in storage, without mixing. Polyester resin is one example of a material that will do this, especially if it's exposed to atmospheric moisture. Moisture tends to kick silicones too.

Also, and unfortunately, many products we use are already close the the end of their shelf-lives by the time we even get them.

Materials made for industrial use and divided into smaller-quantity packaging for hobbyists may sit around for a while prior to end-user purchase, and they're also vulnerable to contamination during re-packaging.

It bites, but it's just the way of things.

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a

Silicone RTV mold making rubber definitely has a shelf life, and it's relatively short (a few months). The only solution I have found is to buy small quantities that I will use up pretty quickly. I don't know of a way to preserve it, but if there is one, I'd love to hear about it!

I've always heard this and do believe it's founded on fact, but I have some I got from Micro Mark almost 20 years ago and I still use it successfully. It is light blue and a reddish color. The light blue part is a bit stiff but it all blends together fine and of one solid color. It cures in the same time (5 minutes) as it always has and is firm and solid.

I use it for "press casting" small parts that only need the molding compound pressed over and around it.

Just an FYI

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a

I've always heard this and do believe it's founded on fact, but I have some I got from Micro Mark almost 20 years ago and I still use it successfully. It is light blue and a reddish color. The light blue part is a bit stiff but it all blends together fine and of one solid color. It cures in the same time (5 minutes) as it always has and is firm and solid.

I use it for "press casting" small parts that only need the molding compound pressed over and around it.

Just an FYI

That's interesting, Mike. I had some Smooth On product that was blue and red. I can't remember which color was which, but the rubber part turned to a wet, clumpy, rubbery consistency that would not dissolve. The catalyst seemed to be fine. Maybe the difference is that mine was for pouring, and yours sounds more like a "putty" type.

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That's interesting, Mike. I had some Smooth On product that was blue and red. I can't remember which color was which, but the rubber part turned to a wet, clumpy, rubbery consistency that would not dissolve. The catalyst seemed to be fine. Maybe the difference is that mine was for pouring, and yours sounds more like a "putty" type.

yeah, it is the putty type. I don't know who was making MicroMark's resin products at the time. One part is a bit stiffer and the other is releasing some liquid but not like a pool .. just wet putty.

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Some of the RTV mold materials definitely last longer than others.  I used to use Kastpro products; anything else I have used since doesn't compare to theirs when it comes to shelf life.  It's best to use the stuff quickly once you have it, particularly once it is opened.  (Advice I often forget/ignore.)  Store the parts A and B apart from one another once they are opened.

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