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Old 2017-01-13, 1:25am
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Speedslug Speedslug is offline
Join Date: Mar 21, 2009
Location: Winnebago, MN
Posts: 2,168


You will want to keep the ratio of 96 type glass to Zephyr to around 5 % or 10 %.

Zephyr is a 104 type glass and it will cool and contract at a different rate than the 96 type glass.
That difference will cause enormous stress at the junction where the two types contact each other and if they don't crack as they are cooling in the kiln they can actually kind of explode days, months or years later with no real warning.

I suggest starting with just one type of glass and adding the very smallest amount of frit you can for your first dozen beads and then increase the amount of frit until the cracking starts up again.

Another thought is to not over work the glass in the flame too much. It's neat playing the glass in its molten state but the yellow flare that gets filtered out with the didymium glasses is called a soda flare because it is sodium that is getting burned out of the glass and that is changing the composition of the glass as its burned off.

My third thought is that there was several discussion threads on here a few years back about some varieties of clear that turned out to not be compatible with itself meaning that just heating it up to shape it and then annealing it would cause it to crack without any other glass or frit added.

I don't remember if Super Clear was one of them or not.
I think there was something called Arrow Springs Kuggler (ASK) clear that had a problem like that but I could be mistaken.

Perhaps doing some searches with the words "clear cracking" in quotation marks can locate those discussions for you. You will want to use the quotation marks so the search engine will give you threads that contain both words or else you will wind up with results containing every thread with the word clear and every thread containing the word cracking.
That would be a list of almost every thing on the forum. this question in as well.

ETA: I copied my answer here from your other post with this question in the tutorial section.
Perpetually Pessimistic. I wish I was Pleasantly Surprised but I'm not surprised anymore.

Last edited by Speedslug; 2017-01-13 at 1:27am.
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