air bubbles are they there for good?

Jabeb · Post by **Jabeb** » Thu Dec 11, 2003 9:44 am

Once you fire a two layer plate and have air bubbles can you fuse it longer to flatten them out or will they bust and leave holes in the piece?[/img]

Tony Smith · Post by **Tony Smith** » Thu Dec 11, 2003 9:50 am

Sometimes, if the bubbles aren't large (under a quarter inch) and they've caused the surface to develop what I refer to as mumps, you can take it back up to full fuse and hold it there for 20 to 30 minutes and the bubbles will reduce and the surface will flatten out. I find 1480Â° for 30 minutes gives me a repeatable surface that is acceptable to me. A longer hold gives you a flatter surface, but you reach a point of diminishing returns after about 45 minutes.

I would suggest that this is a good reason to peek into the kiln at 10, 20 and 30 minutes into the hold and judge for yourself.

Tony

Carol Silrum · Post by **Carol Silrum** » Thu Dec 11, 2003 1:32 pm

Depending on how deep the bubble is I sometimes grind down and break the surface of the bubble, sometimes add frit then refire. Not sure if others do this, but it has worked for me.

Carol Silrum · Post by **Carol Silrum** » Thu Dec 11, 2003 1:33 pm

Depending on how deep the bubble is I sometimes grind down and break the surface of the bubble, sometimes add frit then refire. Not sure if others do this, but it has worked for me.