# Melting Glass? **URL:** \ **Category:** Factual Questions\ **Created:** [July 19, 2017, 11:45pm UTC](https://boards.straightdope.com/t/melting-glass/791682 "2017-07-19T23:45:06Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![Saintly\_Loser](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/saintly_loser/32/4045_2.png) [@Saintly\_Loser](https://boards.straightdope.com/u/Saintly_Loser)\ **Post date:** [July 19, 2017, 11:45pm UTC](https://boards.straightdope.com/t/melting-glass/791682/1 "2017-07-19T23:45:06Z")
Can glass (ordinary glass, like a soda bottle or mayonnaise jar) be melted, or at least softened, enough to reshape in a home oven? I don’t want to actually liquefy the glass, just soften it enough to re-shape it a bit. ---
**Author:** ![engineer\_comp\_geek](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/engineer_comp_geek/32/504_2.png) [@engineer\_comp\_geek](https://boards.straightdope.com/u/engineer_comp_geek)\ **Post date:** [July 20, 2017, 12:32am UTC](https://boards.straightdope.com/t/melting-glass/791682/2 "2017-07-20T00:32:12Z")
Glass typically starts to go soft at somewhere around 1100 to 1500 deg F or so depending on the type of glass. I don’t know about your oven, but mine doesn’t get anywhere near that temperature. If you have a self-cleaning oven, you might be able to soften some of the glass types on the lower end of that range during its cleaning cycle, depending on exactly how hot your oven gets. You’d probably have better luck with a propane torch. ---
**Author:** ![TriPolar](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/tripolar/32/3008_2.png) [@TriPolar](https://boards.straightdope.com/u/TriPolar)\ **Post date:** [July 20, 2017, 12:36am UTC](https://boards.straightdope.com/t/melting-glass/791682/3 "2017-07-20T00:36:09Z")
A propane torch will get it to a plastic state where it can be bent and reshaped. ---
**Author:** ![beowulff](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/beowulff/32/542_2.png) [@beowulff](https://boards.straightdope.com/u/beowulff)\ **Post date:** [July 20, 2017, 1:03am UTC](https://boards.straightdope.com/t/melting-glass/791682/4 "2017-07-20T01:03:33Z")
You can’t really use a set-cleaning oven, because there is a safety interlock that prevents the door from opening until the cycle is finished. A propane torch with a weed-burner head might work for a big object. ---
**Author:** ![Darren\_Garrison](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/darren_garrison/32/92_2.png) [@Darren\_Garrison](https://boards.straightdope.com/u/Darren_Garrison)\ **Post date:** [July 20, 2017, 1:44am UTC](https://boards.straightdope.com/t/melting-glass/791682/5 "2017-07-20T01:44:04Z")
I remember in college taking lengths of Pyrex tube and melting them over Bunsen or Fischer burners (to stretch into micropipettes.) Suckers melted fast. ---
**Author:** ![ZurBob](https://avatars.discourse-cdn.com/v4/letter/z/71e660/32.png) [@ZurBob](https://boards.straightdope.com/u/ZurBob)\ **Post date:** [July 20, 2017, 4:04am UTC](https://boards.straightdope.com/t/melting-glass/791682/6 "2017-07-20T04:04:12Z")
I disabled the door interlock relay on our electric oven for a project… “Clean” temps float between 850-925 F on ours. Wife wasn’t happy. ---
**Author:** ![FluffyBob](https://avatars.discourse-cdn.com/v4/letter/f/ecb155/32.png) [@FluffyBob](https://boards.straightdope.com/u/FluffyBob)\ **Post date:** [July 20, 2017, 5:33am UTC](https://boards.straightdope.com/t/melting-glass/791682/7 "2017-07-20T05:33:41Z")
You can do a fair amount with a torch, it is called Lampworking (as opposed to ‘hot glass’). Lamp working uses certain types of glass, and I do not know if molded glass jars and bottles are of the same material. The problem is the glass object needs annealing to eliminate internal stresses after being worked, which requires a kiln. Generally the glass cracks or even explodes if it is just allowed to cool. I know these thing because Ms Fluffy is obsessed with art glass and half my garage (and many hours of my labour) have been turned into a lamp working / cold working studio. ---
**Author:** ![steatopygia](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/steatopygia/32/3132_2.png) [@steatopygia](https://boards.straightdope.com/u/steatopygia)\ **Post date:** [July 20, 2017, 5:38am UTC](https://boards.straightdope.com/t/melting-glass/791682/8 "2017-07-20T05:38:19Z")
We used to melt beer bottles in an ordinary fireplace. It took a long time and a big fire. The bottles, which we always laid on their side, would sort of slump in the middle. ---
**Author:** ![ticker](https://avatars.discourse-cdn.com/v4/letter/t/d07c76/32.png) [@ticker](https://boards.straightdope.com/u/ticker)\ **Post date:** [July 20, 2017, 6:50am UTC](https://boards.straightdope.com/t/melting-glass/791682/9 "2017-07-20T06:50:11Z")
> [@Darren\_Garrison](#): > > I remember in college taking lengths of Pyrex tube and melting them over Bunsen or Fischer burners (to stretch into micropipettes.) Suckers melted fast. Probably not Pyrex, most likely ordinary soda glass as it has a lower softening temperature and is cheaper. ---
**Author:** ![TheChileanBlob](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/thechileanblob/32/435_2.png) [@TheChileanBlob](https://boards.straightdope.com/u/TheChileanBlob)\ **Post date:** [July 20, 2017, 9:08am UTC](https://boards.straightdope.com/t/melting-glass/791682/10 "2017-07-20T09:08:20Z")
My sister melted a jar of ice cream topping by microwaving it way too long. ---
**Author:** ![MrDibble](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mrdibble/32/114_2.png) [@MrDibble](https://boards.straightdope.com/u/MrDibble)\ **Post date:** [July 20, 2017, 9:53am UTC](https://boards.straightdope.com/t/melting-glass/791682/11 "2017-07-20T09:53:10Z")
> [@ticker](#): > > Probably not Pyrex, most likely ordinary soda glass as it has a lower softening temperature and is cheaper. No, colleges (or, at least, the two I’ve done lab work in) use borosilicate tubing. Pyrex is accurate enough.It’s also common in [lampwork](https://en.wikipedia.org/wiki/Borosilicate_glass#In_lampworking). ---
**Author:** ![Saintly\_Loser](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/saintly_loser/32/4045_2.png) [@Saintly\_Loser](https://boards.straightdope.com/u/Saintly_Loser)\ **Post date:** [July 21, 2017, 12:23am UTC](https://boards.straightdope.com/t/melting-glass/791682/12 "2017-07-21T00:23:47Z")
Thanks, everyone. Looks like my brilliant idea for making some neat-looking odds and ends around the house is a no-go, at least not without an investment in specialized equipment that I’m not willing to make. ---
**Author:** ![engineer\_comp\_geek](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/engineer_comp_geek/32/504_2.png) [@engineer\_comp\_geek](https://boards.straightdope.com/u/engineer_comp_geek)\ **Post date:** [July 21, 2017, 12:58am UTC](https://boards.straightdope.com/t/melting-glass/791682/13 "2017-07-21T00:58:40Z")
Eh? A propane torch will only set you back about 20 bucks or so. It’s not what I would call a big investment in specialized equipment. ---
**Author:** ![Sage\_Rat](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/sage_rat/32/399_2.png) [@Sage\_Rat](https://boards.straightdope.com/u/Sage_Rat)\ **Post date:** [July 21, 2017, 1:00am UTC](https://boards.straightdope.com/t/melting-glass/791682/14 "2017-07-21T01:00:05Z")
Apparently, you can melt glass in a microwave, but you have to raise its temperature to a point where it’s already starting to get a bit soft, so that the atoms can move with the microwaves. A quick Google search is not revealing what the base temperature is for that point to be reached. ---
**Author:** ![md2000](https://avatars.discourse-cdn.com/v4/letter/m/73ab20/32.png) [@md2000](https://boards.straightdope.com/u/md2000)\ **Post date:** [July 21, 2017, 1:21am UTC](https://boards.straightdope.com/t/melting-glass/791682/15 "2017-07-21T01:21:42Z")
Yes, I’ve done some messing around glassworks in the lab with a gas burner… but we’re talking about very thin glass like test tubes, an order of magnitude thinner (and more fragile) than soda bottles or jam jars. ---
**Author:** ![Chopsticks](https://avatars.discourse-cdn.com/v4/letter/c/cab0a1/32.png) [@Chopsticks](https://boards.straightdope.com/u/Chopsticks)\ **Post date:** [July 21, 2017, 1:47am UTC](https://boards.straightdope.com/t/melting-glass/791682/16 "2017-07-21T01:47:39Z")
A blacksmith’s forge is basically a coal-fired barbecue grill with a blower to get extra air in. Even without the blower, not hard to get a red or orange-hot area in the coals. Should be hot enough to soften glass, although I would expect lots of breakage only being able to heat part of a bottle at a time. IANAL, use proper safety equipment, you’ll put your eye out with that thing, etc etc ---
**Author:** ![Darren\_Garrison](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/darren_garrison/32/92_2.png) [@Darren\_Garrison](https://boards.straightdope.com/u/Darren_Garrison)\ **Post date:** [July 21, 2017, 10:21am UTC](https://boards.straightdope.com/t/melting-glass/791682/17 "2017-07-21T10:21:11Z")
> [@Sage\_Rat](#): > > Apparently, you can melt glass in a microwave Now that you mention it, I seem to remember in the 1990s or so one of those arts and crafts shows on PBS featured melting (or at least sintering) bits of glass in the microwave in special containers. ---
**Author:** ![TriPolar](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/tripolar/32/3008_2.png) [@TriPolar](https://boards.straightdope.com/u/TriPolar)\ **Post date:** [July 21, 2017, 11:53am UTC](https://boards.straightdope.com/t/melting-glass/791682/18 "2017-07-21T11:53:09Z")
> [@md2000](#): > > Yes, I’ve done some messing around glassworks in the lab with a gas burner… but we’re talking about very thin glass like test tubes, an order of magnitude thinner (and more fragile) than soda bottles or jam jars. I’ve done some work with soda bottles and the like. Back as a teenager we’d use a propane torch to make bottles into various types of pipes for smoking weed. It takes a while to get enough of the glass hot enough to deform without breaking. You have to slowly heat all around the area that needs shaping otherwise it may just crack anyway. ---
**Author:** ![Saintly\_Loser](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/saintly_loser/32/4045_2.png) [@Saintly\_Loser](https://boards.straightdope.com/u/Saintly_Loser)\ **Post date:** [July 21, 2017, 11:57am UTC](https://boards.straightdope.com/t/melting-glass/791682/19 "2017-07-21T11:57:24Z")
> [@engineer\_comp\_geek](#): > > Eh? A propane torch will only set you back about 20 bucks or so. It’s not what I would call a big investment in specialized equipment. Yes, but that’s not something I want to use inside a small NYC apartment, with two small and curious children running around. Sent from my Nexus 5 using Tapatalk ---
**Author:** ![engineer\_comp\_geek](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/engineer_comp_geek/32/504_2.png) [@engineer\_comp\_geek](https://boards.straightdope.com/u/engineer_comp_geek)\ **Post date:** [July 21, 2017, 4:13pm UTC](https://boards.straightdope.com/t/melting-glass/791682/20 "2017-07-21T16:13:08Z")
> [@Saintly\_Loser](#): > > Yes, but that’s not something I want to use inside a small NYC apartment, with two small and curious children running around. Good point. [Next page](https://boards.straightdope.com/t/melting-glass/791682.md?page=2)