Smoothing silicone mold interior with a second coat?


Active Member
I have a 3d printed master, don't require tight dimensional accuracy, but do want a nice surface finish. The master has deep pits that would be very difficult to properly sand.

Would it be possible to remove the 3D printing lines by creating a mold, and then applying a thin second layer of silicone to the interior? Just pour some in, rotate it around, then let it drain out.

This seems plausible in my head, but I wanted to do a sanity check before I experiment with some expensive rubber.


I don't think you would get a result you want. even filling one divot in a silicone mold will leave evidence on the cast. Rolling fresh silicone over a cured mold would likely result in a product devoid of detail. The mold will always only be as good as the master from which it is taken.


Master Member
I think it would be better to fix you master. There are a number of things you can do to fill in the master and smooth it out. But if you can show a picture of the master, perhaps I or others could better suggest a method to fix your issue.



Active Member
can coat the master with a resin coat to fill in print lines - works well and is easily sanded to get a perfect finish - xtc 3d i think its called


Active Member
Thanks everybody, I tried coating the inside of a clear disposable cup and silicone is just too thick to flow properly. I'll just sand the master, it's possible but I just hate the effort involved.

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