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Author: Subject: Heating mantle/variac
magnet
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[*] posted on 4-10-2015 at 06:11
Heating mantle/variac


Hello all, first post after months of lurking. I bought glassware,a variable temp heating mantle with stirrer and a variac. Total novice at chemistry and am only looking to distill ethanol and use it for soxhlet extractions. So I set up the glass to distill the ethanol from a bottle of Everclear, plugged the mantle into the variac and ran it at 50V (lowest setting that would run the mantle). Thermometer never read higher than 74°77° but at least the ethanol came over. The temp setting on mantle was all the way up during the distillation and this concerned me because the mantle is supposed to reach 450° F which it obviously didn't. So, am I doing it wrong with the variac and can use mantle straight through the wall socket. I'm assuming the variac is only needed for one of those ring style heating mantles with no controls but we all know about assumptions. Any enlightenment is greatly appreciated.
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Metacelsus
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[*] posted on 4-10-2015 at 07:49


If the heating mantle has temperature control built in, you don't need the variac.



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[*] posted on 4-10-2015 at 07:53


Show us a picture of the mantle. Is it equipped with a power setting knob?

If the mantle has a standard electrical plug suitable for a standard 120VAC receptacle it is likely you can just use it that way.




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[*] posted on 4-10-2015 at 08:22


Doesn't seem to want to let my attached pics snow up but it's got a standard 3 prong plug and a knob for heat and one for stir so it's definitely leaning toward variac not needed
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[*] posted on 4-10-2015 at 08:43


Doesn't seem to want to let my attached pics snow up but it's got a standard 3 prong plug and a knob for heat and one for stir so it's definitely leaning toward variac not needed
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[*] posted on 4-10-2015 at 08:45



[img]http://IMAG0148_zpsfbhc4esl.jpg - 32kB[/img]
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bob800
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[*] posted on 4-10-2015 at 09:13


That kind of mantle is supposed to be plugged directly into the mains.
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[*] posted on 4-10-2015 at 15:56


If your objective is to get 99% EtOH then distilling won't get you there. Everclear is 90%, 180 proof. On the other hand if you want to do some chemistry I'm told that fractional distillation from ethanol/cyclohexane can get you to 99% but you have to exclude water from your apparatus. Flame your glassware and include a CaCl2 drying tube in the setup.

Attachment: etoh001.pdf (615kB)
This file has been downloaded 328 times





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[*] posted on 6-10-2015 at 05:08


Thanks chemrox, but at this nascent stage where I am such a paragon of ineptitude that I don't even know that I didn't need a variac for my mantle I think you'll agree disaster is more likely in my future than any kind of real chemistry. Hehe, ill read up and chip away at the stone though.
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[*] posted on 6-10-2015 at 08:44


Question: The stirrer in the mantle will still run when on a variac, because the sine wave is just shortened, not really truncated, right? Don't try to run a motor with a light dimmer, since it isn't a resistive load.



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[*] posted on 7-10-2015 at 07:28


Stirrer still worked with variac but the magnet did seem to lose its center and go astray from time to time. Turned it off and restarted when it did, hopefully works better than when it's at 50V instead off 110. Ugh...reverse that.

[Edited on 7-10-2015 by magnet]

[Edited on 7-10-2015 by magnet]
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