I'd be curious to know if the isopropyl myristate betrays you. I had an issue with a mold at the exact location I had used the myristate to smooth some fur. The problem wasn't evident with the mold, however it was ruining every resin cast out of it. My silicone was old when this was occurring.

I don't risk using it anymore, even though the manufacturer recommends it and nobody else seems to be having problems with it.

It seems to have not betrayed me! I just posted an update image with the resulting tests. I had read about someone else who had the same issue with Myristate but was recommended it by another artist so I wanted to test it. Seems to work just fine with my nearly 1 year old left over Mold Max 30 (I was certain it wouldn't cure, but what'dya know?! It did!) and it worked fine with this new stuff, Mold Star 20T. I cast resin in both molds (also nearly 1 year old resin... which also still is good it seems!) It was a bit bubbly but that's because I didn't bother pressure casting it and I think the fur texture held onto the bubbles. It cured just fine.

I did leave it to dry for a few days after using the myristrate before molding. Maybe there was some moisture left from the myristrate and that caused your issue? Or maybe it was just a day that ended in y because silicone and resin are touchy for no logical reason sometimes.

Ahh, glad to hear everything worked! I'll let my myristate dry for a while in future, that might've been it.

And you aren't kiddin' about silicone and resin being touchy. It's enough to make one superstitious.

Oh and thank you for the detailed update, I appreciate it.

Not a problem! I'm glad to hear people like this sort of thing. I'm not quite the social art posting type but I've always loved seeing detailed process stuff and learning from it, so it's a bit of a struggle for me to post things sometimes.