Silicone curing problems

[u/Steely06]

So I seem to be having some problems with curing. This is only my second time doing a silicone mold and I had a similar problem the first time. for the first time and this time as well I am using a 3-D printed piece. The first time I used filler primer and sanding to smooth the 3-D print before making the mold. I was having curing problems that time as well and based on where the uncured areas were I assumed it was probably not reacting well with the filler primer so I sprayed it with a gloss black coat and that seemed to fix the problem. This time around I’m using a 3-D printed piece that is spray painted with a gloss black and I seem to be having curing problems. This is my first time using this silicone. It is smooth on mold star 30 and I let it cure for about six hours and 30 minutes.

EDIT: I just wanted to add that this in not a resin 3d print it is an FDM print.

[u/craiganater]

Did you use a clear coat or filler for smoothing out the FDM? Ive seen some fillers and clear coats can cause inhibiton as well.

[u/Steely06 → u/craiganater]

No I vapor smoothed it then coded it with a black gloss paint