Question about silicone curing

[juntari]

I've started making a mold of a sculpt using mold max 20. I brushed on a very thin layer and was going to put more on but its still very tacky. it doesn't stick to my finger but my fingerprints show when i touch it. Its been over 2 days. I'm guessing its a mixing problem, I've done another mold with the same materials and didn't have a problem. So my question is should I add another layer and hope the hardener in the second layer will cure the first fully or should i wait and let the first layer air dry? Right now it seems rigid enough that I would be able to peel it off but definitely not 100% cured.

Also, could the silicone have expired? Does anyone know the library life of a gallon of silicone?

 

[clonesix]

Silicone expire? No, but the catalyst does.

Next question: What was used for the sculpt? Did you seal the sculpt?

If it was sealed, and it is only a matter of old catalyst, you can try mixing the next batch a little hotter and it will kick the first layer.

 

[juntari]

I used Chavant NSP for the sculpt, didn't seal it though, last one I made turned out great without being sealed so I assumed the same for this one.

What does making the next batch a little hotter mean? adding more catalyst?

 

[Superkrates]

Is it colder than 70 degrees F? Cold will slow the 'kick' immensely. Hell, I place silicone molds in the freezer for degassing for 24 hours and know that some slow-kick silicones will last over a week in the freezer without gelling - useful for storing excess mixed silicone while prepping next mold.

 

[juntari]

Good to know, it might be the temperature, the side closer to the heater does seem more cured. I'll place it in front of the heater and rotate it and see how it goes, thanks for the info!