I am troubled too by this issue. Didn’t realize it was the curing inhibition from the mold after quite many failures to cure PDMS even at 110 degree C.
I only used Grey V4 on Form 3 and it was IPA washed, UV cured and even sanded multiple times for surface finish. Yet the PDMS region very close to the grey resin still remains tacky. The mold itself is also ruined because of this half-cured PDMS layer that gets transferred to everywhere it touches.
I guess I’ll start with some clear coat spray. But I am worried that the coat applied contains inhibitor for PDMS , too. Since I probably don’t have access to any airbrush, I would try spray can or dipping in a container.
Sylgard 184 lists urethane containing material inhibiting the curing. Does this mean I should totally avoid using polyUrethane clear coat?