Re-fire brittle glass

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RosanneH
Posts: 3
Joined: Wed Mar 06, 2019 12:30 pm

Re-fire brittle glass

Post by RosanneH »

I am such a newbie. I have a suncatcher project that has pointed tips of 3mm glass hanging over 2mm clear glass (I have since learned about the 6mm rule)....the points are very brittle, I had a full kiln (8 of these in it) and I did peak about 2 seconds at 564 degrees I opened the lid on the skutt kiln about 6 inches for 2 seconds...not sure if my problem is thermal shock or 6mm related but will a refire help strengthen the glass projects? I did a spectrum fusing schedule for a contour fuse in a skutt pottery kiln.
Thank you
Ed Cantarella
Posts: 155
Joined: Mon Feb 26, 2018 3:49 pm
Location: Highland, Michigan, USA

Re: Re-fire brittle glass

Post by Ed Cantarella »

The tips are probably just brittle. Refiring won't help them, other than if you do a full fuse and cause them to retract(losing the sharp tips.

Opening the kiln: extremely pointless to look in the kiln between 100-800+f. You can thermal shock(break) a piece going either direction in that range. If you MUST look, wait until you are at say 1000-1200f. Nothing will be tacked together yet, if something broke spontaneously, you will be able to pull the pieces apart once cool and maybe try again. E.g. you cut 20 pieces for a rabbit which are laid on a sheet of clear glass. The sheet glass might break but the smaller rabbit pieces generally won't(small pieces take shock a lot better). You at least don't have to redo the rabbit. The sheet glass becomes whatever. The universal cure for peeking is another kiln. That or breaking a lot of glass and getting tired of testing the kiln gods' patience.
HER last words were, "I'm melting, melting . . . " Dissenting opinions generally welcome for comic relief or personal edification. Sometimes both.
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