I was more than a little bit concerned that any of a number of materials I am planning to use in an armature might inhibit the cure of the platinum silicone.
So I made a little test. This is about 2 fluid ounces of ecoflex 00-20, tinted with silc-pig.
It obviously wasn't inhibited by anything I'm going to use.
The stuff is way softer than I expected however it poses no problem allowing access to the materials underneath it.
It can stretch 960% before tearing!
Bonus: it makes wall crawlers!