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Alumilite Question

I assume someone on here is familiar with the Alumilite family of moulding/casting materials, so maybe someone can help me. I recently bought a casting kit (alumilite regular & Dow Corning HS3, and I must say this is some amazing stuff, and I'm having lots of fun with it. But I recently poured the silicone for several moulds, and accidently used about 30% less catalyst than was specified (didn't realize my mistake until the next day). As of 48 hours, the time when the rubber has normally cured, these moulds are still very sticky and soft, though they have at least started to cure and the material will not transfer to a finger. My question is, will they eventually cure if I just leave them a couple more days, or should I just scrap them and start new ones? I really don't want to waste these moulds as the material does not come cheap. Thanks for any advice.

Reply to
Chris F.
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Chris- I've never tried "skimping" the catalyst, but I suggest you ask Alumilite corp or their user forum, at

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Reply to
Dave Plumpe
150 degress F in an oven with a bowl of water for increased humidity might work. Even catalyzed silicones often need water to cure.
Reply to
Kel

Immerse the mould in the water??

Reply to
Chris F.

On Mon, 06 Mar 2006 23:51:34 GMT, "Chris F." wrote in :

No, I think he means put both the uncured molds and a bowl of water in the hot oven.

The water from the bowl will humidify the air.

Both the heat and the humidity may catalyze the reaction.

It's a non-destructive test. The heat and the moisture from the bowl of water are sufficiently different from room conditions to possibly help the process, but not intense enough to do any damage.

What have you got to lose? It might work. If it doesn't, you won't have done any more damage to the uncured molds. Worst case is you have to start over anyway.

Let us know how it turns out. :o)

Marty

Reply to
Martin X. Moleski, SJ

It's been almost a week since I poured those moulds, and they haven't made any improvement for several days, so I decided to scrap them and start over. Easier said than done though, because the uncured silicone has made a gooey mess of my original parts (old radio knobs in this case), and will be quite a job to clean. I probably wasted about $5 worth of silicone at most, so I guess it's no huge loss. Lesson learned, anyway..... Does anyone know of a cheaper source of the HS3 silicone? I'm paying $39.99 / lb here in Canada.

Reply to
Chris F.

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