Bubbles in my mold.

bobbyfett · Post by **bobbyfett** » Thu Sep 29, 2005 7:54 am

Well, I just made my first mold last night!

Unfortunately some air was trapped in some tiny detail areas. I kind of expected it to. So now I've got some little bubbles in my mold.

Can I just spread a little more rubber on these areas and squash the part back in the mold to fill them in? That should work, right? Has anyone tried this? Lastly, should I have put some talc on the master first to avoid the bubbles in the first place?

Sparky · Post by **Sparky** » Thu Sep 29, 2005 8:49 am

I have not had luck repairng a mold in this fashion, the rubber ended up as a little mess there. Ken has used it once to add material to a two part mold were he had a pocket form along the seam. It has been done. If you coat the surrouding area with a Vaseline/naphtha mixture to prevent excess rubber from bonding to those areas it might work.

bobbyfett · Post by **bobbyfett** » Thu Sep 29, 2005 9:23 am

What if I am really careful and just put little dots of rubber into the holes? Will that work?

Sparky · Post by **Sparky** » Thu Sep 29, 2005 1:53 pm

That might work, as long as you don't pressure cast you won't see to much trouble. But if the hole is only plugged, when you pressure cast it the rest of the air will collapse and the casting will appear to have welts and blisters.

If you smear the area around the repair point with Vaseline any rubber that spills can be left to cure then just pealed off, this is how the seam in a two part mold is kept.