Silver Alchemy Cold Mold Silicone Rubber Compound

[FranOnTheEdge]

Hi,
I have two pots of Silicone rubber moulding compound - one blue and one purple. (from Silver Alchemy)
The other day I tried to mix a small amount of each together, but found that the mix crumbled away in my fingers before the colour was blended, and well before the end of the "4 minutes working time at room temperature". It was one of the hottest days of the year, but this is the UK we are talking about, not the Arizona desert.
So... would putting the blue (and the purple???) compound into the fridge before attempting to mix them together again help at all, or is the blue stuff dead?

The purple remains feeling very maleable, but even before mixing the blue felt very stiff.

Now it's about 4 to 6 years since I last tried using this stuff, so perhaps it could be dead, but there's lots left and I don't want to waste it if it's rescuable.

Otherwise, can I buy a tub of just the blue stuff?

Fran

[Polly]

I looked at a few types of silicone molding compounds, and found that most have a shelf life of 6 months to 1 year from date of purchase.

"As silicone ages the catalyst loses its reactivity and eventually will not have the ability to perform the chemical reactions necessary to convert the combined parts into a usable rubber."

So I am sorry to say, that I am pretty sure yours won't work well any more.
Some sites do say it helps to store the unmixed compound in a cool or cold location, but I am not sure how many months that will extend the workability.

I haven't seen the components available separately - and I would be hesitant to order just one half, and then discover that chemicals in the other half don't work quite right any more either.

[Metalman]

I suspect your molding compound is 'dead'
I found that mine lasted well beyond the stated 1 year shelf life but I think it was at about 3 years when I used it and it seemed to have gotten lumpy - still worked but not best condition.  You can get separate components from sculpture supply houses some of the time - you problem will be matching the materials - and then expense. I suspect you will do best to get a new batch when you are ready to use it.
One very important factor when using these materials is to make extra sure that you don't cross contaminate the materials. It may have been that a little bit of your  purple got into your blue and catalyzed the entire container while it was on the shelf.
Hope this helps.