Oh for something large I’d definitely go tin-cured. Platinum-cured would be punishingly expensive for a large project, and it’s definitely harder to work with. I’d only consider platinum-cured for small pieces where microscopic detail was important.

I’m not aware of any quick test to perform to tell if they’re unlabeled–both would come in two parts. I’d say generally speaking I would assume silicone is tin-cured unless it’s specifically called out as being platinum-cured. Tin-cured is usually the default, more economical, and easier to work with option.

Whilst this may not help you or I specifically I will drop a tip I found that suggests that using a polyurethane paint barrier may work fairly well. Whilst it’s hardly ideal for detail or long term mold life hopefully that may help someone who just needs a quick one off job or something like that.

I haven’t. I settled on platinum cure because I wanted microscopic surface accuracy. I have absolutely zero patience for polishing, so I wanted my pieces to come out of their molds pre-polished.

Really glad to hear it! Hope your crafting adventures turn out many amazing things :)

Have you tried using Tin Cured Silicone?