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Erlenmeyer flask on an electric stove = disaster!
Posted: Mon Apr 25, 2011 3:52 pm
by jason.loxton
It is possible that people here know this, but I didn't, so I figured that I would post my hard-earned wisdom. Ratchet was kind enough to hook me up with a 2 L borosilicate erlenmeyer flask for making starters. I have a electric coil-style stove (as do most people, I assume). I went to use it the first time this weekend. Set it to high, and then turned it down to 4 when it boiled. It was happily rocking along for at least 10 minutes at this low heat when suddenly to bottom gave out, spilling the entire contents across my stove top. Upon inspection, it has a circular crack nearly around the circumference, and a one inch wedge missing. From this thread it looks like electric elements and these flasks don't mix (at least in the long term). Now I know, and as GI Joe says: "Knowing is half the battle!"
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Jason
Re: Erlenmeyer flask on an electric stove = disaster!
Posted: Mon Apr 25, 2011 3:55 pm
by mr x
Bugger. Need those trivets on coil stoves...
Re: Erlenmeyer flask on an electric stove = disaster!
Posted: Tue Apr 26, 2011 4:52 pm
by ratchet
I wonder if a 1/2" thick aluminum plate between the burner and flask would solve that issue?
Re: Erlenmeyer flask on an electric stove = disaster!
Posted: Wed Apr 27, 2011 5:29 am
by mr x
That might do the trick as well.
Re: Erlenmeyer flask on an electric stove = disaster!
Posted: Wed Apr 27, 2011 9:09 am
by Garak
Aluminum might be too good of a heat conductor for this task. I don't think it would be much different than putting it right on the element.
Re: Erlenmeyer flask on an electric stove = disaster!
Posted: Wed Apr 27, 2011 12:50 pm
by ratchet
Garak wrote:Aluminum might be too good of a heat conductor for this task. I don't think it would be much different than putting it right on the element.
I don't quite understand what you mean... if the issue is too much heat, then just turn the burner down.
From what I understand, the problem is with all of the heat being concentrated at the point where the coil touches the flask .... IE: uneven heating
The alternating hot/cold/hot/cold from the coils (Hot on a coil, cold between coils) causes uneven material expansion... which leads to material failure.
The aluminum would ensure a constant heat across the whole bottom of the flask due to it's high thermal conductivity (which is why all of our lab's hot plates have aluminum tops)... thus, eliminating the uneven heating issue.
Trivet would do the same thing.