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Heating Ceramics?

Is it safe to heat ceramic bowls and cups and stuff on a hotplate or cooktop? Like plain white ceramic stuff.
BTW: The piece in question is almost certainly stoneware, not porcelain or earthenware.

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8bitgamer1310 months ago

What's the highest temperature/shock ceramic can endure? I'm experimenting with heat shields.

seandogue6 years ago
Pyrex containers will work great in ambient heat, (for instance, in an oven), but don't put one directly on a gas burner. I learned the hard way when still a wee lad and broke my mom's 1qt pyrex measuring cup. She was not pleased. Yes, 45 years later I still remember the event as if yesterday. Not pleased at all.
I had a pyrex mesuring cup that completely exploded when I pulled it out of the oven, so don't let it cool to quickly!
Although theoretically, that should not have happened to you (unless you dunked them in cold water immediately after removing from the oven) Pyrex or not, I'm not so sure measuring cups should be used in an oven. I have had four pyrex baking dishes for several decades that don't experience that problem, but ever since I broke mom's pyrex measuring cup on the stove I use them for one thing only...measuring. I'd be more than glad to experiment with someone else's cups to find out exactly what the cause and/or limit is, but I think maybe you have it...rapid temp change.
LiquidLightning (author)  seandogue6 years ago
Isn't pyrex glass though?
Yes. But it's designed to be used in high heat.
Way back in the olden days (okay, the '60s and '70s), there used to be many glass and porcelain cooking vessels available. ALL OF THESE used a wire "spacer" that sat on top of the electric "burner" to create a small, but absolutely vital thermal space/cushion to keep the vessel from expanding at far too great a rate on the bottom. This kept the vessel from breaking. I suggest you get some tie wire for a fence or concrete construction for this use. If you have an old wire coat hanger, you can use that as long as you take the coating off. The main thing is that the wire be some sort of UNCOATED steel. Shape the wire in either a star or spiral pattern.

Don't be fooled into trying to use a glass coffee pot, as they are not meant for burner use. Yes, they sit on a burner, but it is a much lower temperature than stovetop burners and they are heated from both the inside and outside when you make coffee.

Qa
NachoMahma6 years ago
.  Most porcelain labware can be heated without breaking. Most tableware cannot.
lemonie6 years ago
If it's ovenware, designed to take heat you may get away with it. But like rick' and Jack' say, not really a good idea.

L
Rumor has it that fired clay, the stuff most coffee cups are made of,  is kind of a mediocre conductor of heat. For that reason I would guess that you'd have trouble getting heat to flow through the bottom of the cup and into your coffee, or soup, or whatever. It might take a while to heat up.

But you should not let yourself be stifled by convention.  If you want to heat your coffee cup over an open flame, I say do it!  But wear your safety glasses though, because the damned thing might just crack in half and spill your coffee everywhere.  I know that happens when you try to heat stuff in soda-lime glass, like the jar the grape jelly or the salsa came in.  I think it has something to do with uneven heating and different parts of the the structure expanding thermally at different rates.   Anyway the damn thing breaks, and then you realize that just isn't going to work.

Borosilicate glass is another matter.  That stuff is great for cooking, and for chemistry experiments.  You can heat it over an open flame and it won't break.   I've even heard/read rumors of people making homemade boiling flasks from old incandescent lightbulbs. 

Anyway, regarding heating your coffee cup, I know "try it and see what happens" might not seem like much of an answer.  I mean you probably could have thought of that by yourself.





LiquidLightning (author)  Jack A Lopez6 years ago
Since it sounds safe enough , I'll try it, but outside, with water (Don't wanna waste any precious coffee do we?) Anyway though, it's not for coffee, the experiments in my textbook that i'm required to do, so no skipping, call for a crucible, and it'll be like, a week before the one I ordered online comes, so I need a suitable replacement, but, thankfully, it won't be used for like, super high temps, just like, a hot plate. Anyway, thanks.
rickharris6 years ago
uneven heating may well crack your china. So beware. Not recommended