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Cooking a roast showed me why my glass pieces crack during cooling
I was making a roast the other day and saw how the outside cooked faster than the inside. It got me thinking about how heat moves through things. In my glassblowing, I've had a lot of pieces crack after I take them off the pipe. I used to think it was just bad luck or my annealer acting up. But now I see that when I heat the glass, I might be rushing and not warming it all the way through. Like with the roast, if the heat isn't even, the stress makes it break. So I started turning my piece more slowly in the glory hole to get a uniform heat. This small change has really cut down on my cracked work, and it makes sense now.
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terry_webb986mo ago
Would you believe I used to think quick heating was fine? But wren_scott39 is right, slower heating for the base makes total sense now I've tried it.
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wren_scott396mo ago
Oh man, I used to have that same problem! I found that if I didn't heat the base of my piece as thoroughly as the rest, it would just pop. Now I make way smaller, slower adjustments with my flame and keep it spinning steady for way longer before I even start to shape it. It takes more time but saves so much heartache.
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thea_harris976mo ago
Yeah that's totally it, you really gotta baby the bottom part lol. I cracked so many pieces before I figured out the base needs to be just as hot, if not hotter, than the rest of the glass when you're starting. My rule now is to keep spinning in the flame until the whole thing looks like it's moving as one thick, slow liquid, not just the top. If the base is stiff at all, it's just holding onto stress and waiting to blow.
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