quintorpian
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thermometer for distillation HELP!
Hi there,
I'm here on behalf of my chemistry-loving son.
A few months ago he bought a distillation set from Laboy. Since then the thermometer got broken. I have asked Laboy if they sell thermometers
separately but have not heard back from them yet. And their site doesn't list them.
Could anyone help me with where i could get a new thermometer. We bought one from a new zealand website but it is slightly too fat to fit into the
thermometer adaptor that comes with the distillation set. We need 6mm width tops. Are there standard widths for these things?
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j_sum1
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I bought a couple of these: http://www.ebay.com.au/itm/271931276313?_trksid=p2057872.m27...
They actually arrived yesterday and seem to be quite good. There are plenty available through ebay but you do have to be careful -- what the picture
shows may not always be the same as what you get. My previous one had a scale that was almost unreadable. Thermometers also attract a reasonable
shipping cost compared to other items -- which means that what looks like a bargain may not be.
Get two or more. they are easy to break.
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careysub
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What is the thermometer adapter made out of?
Personally - I have decided to abandon glass thermometers and use thermocouples. Handheld thermocouple thermometers are available at reasonable prices
on eBay.
Type K thermocouples are the most common, but type T are bit more accurate in lab temp ranges.
Two options are to use stainless steel probes as is (they are likely too slender for most adapters, so an inert filler might be necessary) or get
thermocouple wires and use a glass tube, sealed at the end (and then you can get the exact width you want).
I also plan to seal the end of a glass tube and
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quintorpian
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thanks both of you for your replies. I might try out the thermometer initially and will think about the thermocouple idea.
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j_sum1
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http://www.dx.com/p/0-9-lcd-digital-thermometer-for-oven-50-...
These are all over the net. (At prices better than this particular one too.)
I find mine very useful (and droppable). I haven't used it for distillation but with a decent wrap of teflon tape I am sure that it would work.
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quintorpian
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thanks that's interesting. might try the digital thermometer sometime. Is the teflon tape just to wrap round it and make it thicker so it fits snugly
in the adapter? Bit new to these things
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j_sum1
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Yeah. They clock in at around 4mm diameter. You need to add some thickness so that they fit snugly in a thermometer adapter. I have never done it,
but if I did, teflon plumbers' tape would be my first attempt.
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careysub
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You can easily get PTFE ("teflon") tubes and rods:
http://www.mcmaster.com/#rods-(made-with-teflon-ptfe)/
If you are handy with a drill (or have a drill press), a vise, and a set of drill bits (an index set gives the best choice), you can make an adapter
that fits exactly,
LIkewise - of your adapter is PTFE you could drill it out a bit bigger to fit.
You could probably also nest tubes inside each other pluro-stopper-style to get the best ID and OD.
[Edited on 16-9-2015 by careysub]
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Funkerman23
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I am very sorry to hear that it broke. When I was buying from Laboy they sold not only good mercury thermometers but jointed ones in 76mm,50mm and 25
mm immersions. ( I can email you a copy of the old catalogs I have if you wish, but PM me for that). You are very right in that they no longer list
them but they may have them for those who have the SKU( serial numbers). I am shocked and more than a bit worried to hear this. As for where to
buy.. I'm sorry if this sounds dumb but without knowing where you are, anything I might recommend would be a shot in the dark. I don't like suggesting
ebay but Kantu200, Avogadro's science supply, Nanshinsales, Deschem. All these suppliers have been good to me. But I can't say that without the
disclaimer that you still need to determine for yourself if any one supplier is right for you.
" the Modern Chemist is inundated with literature"-Unknown
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Praxichys
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I just poke a type K down a ground glass well like this:
http://www.ebay.com/itm/New-Glass-24-40-Thermometer-Well-Ada...
You can also get some 6mm glass tube and seal the end in a flame, and push the thermocouple down into that.
Check out "Nitric Acid Day" on YouTube.
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wg48
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I bought some cheap glass thermometers recently. The scales look like they a printed on so they may be useless for direct immersion in many liquids.
It will be essential to use them only with a thermometer adapter to avoid the scales disappearing.
I also noticed their readings differ by up two degrees and I could find no calibration marks on them. The inner diameter of the capillary tubes are
very small which makes them difficult to read.
I got two of these easy to read and more robust useful for monitoring the temperature of a brazed hot plate (repurposed electric kettle).
http://i.ebayimg.com/00/s/MTAwMVgxMDAx/z/Od8AAOSwpDdU~mLc/$_...
[Edited on 1-10-2016 by wg48]
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Dr.Bob
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I still have a few used thermometers in Hg and non-Hg, in standards straight and 10/30 jointed styles. They are listed at the end of the most recent
spreadsheet in the glassware looking for a good home thread. There are many older ones that were made in the US, some are very high quality, most
are better than any new ones I have seen.
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Sulaiman
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I would go for something like this
http://www.ebay.co.uk/itm/220V-PID-REX-C100-Temperature-Cont...
initially it can be used just as a thermometer,
if an interest in chemistry continues then the heating control feature will be very useful.
find glass tubing of suitable diameter for your adapter and make a thermocouple pocket
thermocouples are much more durable than glass thermometers, and are ridiculously cheap.
using ac power for a thermometer is not as convenient/portable as a battery powered unit
and you will have exposed power wiring if not encased
but overall a good choice for hobby chemistry I think
(I have one and I like it)
If not then maybe http://www.ebay.co.uk/itm/TM902C-LCD-K-Type-Thermometer-Temp...
meter + thermocouple cheaper than a glass thermometer
P.S. whatever thermometer you choose,
your (son's) first task is to calibrate it, 0C = melting ice, 100C = boiling water at 1 atmosphere pressure etc.
[Edited on 2-10-2016 by Sulaiman]
CAUTION : Hobby Chemist, not Professional or even Amateur
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