Trying to recover from a failed mod, I needed to desolder some stacks of copper discs. To do this I needed to heat them with my mini torch.
I figured the safest way to do this would be on a heatproof Pyrex lid from a Corning Ware dish.
Bad idea !
The Pyrex literally exploded Sending chunks and shards of glass flying. What you see in the picture is just a small bit of the picture. Glass is covering the table, my lap and all over the floor, not to mention red hot copper discs that burned into the table. I was lucky I wear glasses.
Anyway, don't try this. Pyrex may be oven safe, but it's not heatproof.
It does develop glass fatigue and that can cause the shattering. If it was your grandmother’s pyrex i might use it as a serving dish instead of using it in the oven.
I was going to do it on my cement balcony, but figured I’d get grit embedded in the solder. The Pyrex seemed like a nice clean alternative.
…and it didn’t shatter, it exploded!
The heat was most likely not even causing much stress in the glass, in an oven it heats up evenly and cools down evenly . It would be like taking it out of the oven and lowering one edge in cold water
Cement isn’t a very good choice either, it traps water similar to limestone and can also explode, a brick is truly heatproof (since they’re fired) or there’s plenty of other truly heat resistant material.
Glad you ok. I consider myself lucky I wear glasses when modding, I doubt I’d take the time to always be wearing safety glasses but I’ve always got my glasses on when working.
You want “firebrick” — the kind at the back of a fireplace.
Ordinary red brick can absorb water and cause a steam explosion just like some kinds of porous rocks can.
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General thought — I usually find that if I post what I believe to a Google search box first, I get newer and better information than I had in my memory. As the Red Queen said to Alice, it’s a poor sort of memory that only works backwards.
For any facts newer than what we know, there’s Google ….
Something marketed as heatproof under domestic kitchen use means oven/microwave. Hitting it with direct flame is a looooooooong way out from the “heat” in “heatproof”.
I have used what is called "pavers", for years. I have soldered all my projects on them and have never had one crack, explode, break up or show any signs of a problem. Believe me, I have some some big soldering jobs on them and I heat all my copper on them, to soften, so they see lots of heat. Of course, I do that in the garage, so they don't see any outdoor moisture, but they see high humidity. They are concrete paver stones.
Anyhow, they are cheap and readily available at most big box stores like HD and Lowes.
Bricks are pretty safe cause you keep the one you use as a fire back indoors away from water/humidity, concrete is outside absorbing any elements it can. No a brick from outside won’t be a good choice either cause its likely to have moisture in it but if you get one or two to keep at your work area and not in the garden path you’ll be fine.
I remember readings some rumors about the new Pyrex being soda glass to avoid people using it for cooking up illegal drugs. That’s why old pyrex is really desirable for cooks.
I had heard about this but had not really looked into it, i jut checked, i have a new pyrex dish made from the cheaper and more dangerous material
I once had a pyrex lasagna dish explode, i had trouble cleaning it and a roomate suggested heating it up on low on the stove, after about 15 mins it exploded. No injury luckily, i think the direct heat caused it to blow, it can take high temps but not in direct contact with the heat source, if part of it becomes hotter then the rest i’m guessing that what causes the explosion. I am now concerned about my current dish, i use it in the oven to cook chicken breast, french fries and a few other things, i may have to reconsider that
