itsafineday
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melting point apparatus
Do any of you have experience enough with melting point apparatus' to be able to recommend reliable models to look for on the second hand market?
I'm also assuming these are more accurate / repeatable and easier to use than a thiele tube but perhaps I should be corrected on this.....
Thanks !
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itsafineday
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I bought a Mel-Temp II on an auction site for 40 dollars .
Does anyone out there know what size capillary tubes to get for this melting point apparatus?
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AvBaeyer
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Melting point capillaries are all a standard size. They are available from Amazon in 100 tube packs.
I recommend an older Mel-Temp as the best instrument for the home lab.
AvB
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itsafineday
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Quote: Originally posted by AvBaeyer  | Melting point capillaries are all a standard size. They are available from Amazon in 100 tube packs.
I recommend an older Mel-Temp as the best instrument for the home lab.
AvB |
Thanks AvBaeyer for this very helpful response! The correct capillaries are on the way to me.
I was confused because deschem sells a few different sizes of fine glass tubes and they call all of them melting point capillaries. None of them are
the standard size of 1.5-1.75 mm od . I suppose these are for use with thiele tubes .
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Dr.Bob
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Yes, just make sure that they are sealed at one end. I have seen many people sell open ended capillaries as melting point tubes, including some on
Amazon, which are not well marked as open at both ends.
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morganbw
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The ones I got from deschem are open on both ends. It is very easy and fast to seal one of the ends. It might pay to look online for techniques for
this because I have seen some, online, look like a noodle when done.
They were/are fine for me. I use a thiele tube for melting point and sometimes for a boiling point, it still requires one end of the capillary to be
sealed.
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itsafineday
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Thanks for the heads up Dr. Bob.
My glass thermometer looks very vulnerable in the mel temp. I have seen mention of using a conductive sleeve in the thermometer well so that a digital
thermometer can be used. Does anyone know where to get an appropriate conductive sleeve for use with a mel temp II?
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DavidJR
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| Quote: Originally posted by morganbw | The ones I got from deschem are open on both ends. It is very easy and fast to seal one of the ends. It might pay to look online for techniques for
this because I have seen some, online, look like a noodle when done.
They were/are fine for me. I use a thiele tube for melting point and sometimes for a boiling point, it still requires one end of the capillary to be
sealed.
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I agree, it really only takes 5 seconds with a cheap butane torch (or similar) to seal one end.
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AvBaeyer
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itsafineday,
I do not understand how your glass thermometer looks "vulnerable" in your mel-temp. It should be perfectly fine if you are reasonably careful.
I do use a digital thermometer when I need a mp higher than my best thermometers go. You do not need any sleeve. I just insert the probe and push a
piece of thermal insulation alongside it that it is tight in the thermometer well. Works well and mps are not different when tested with standards.
The nice thing with the digital thermometer is that you get a "corrected" mp for high melting substances.
AvB
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itsafineday
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I've started to appreciate (and romanticize) the quality and materials present in lab stuff from before 2010ish. I guess I just really like this big
beautiful pre -2000 mercury thermometer and I'd rather not break it. I'm weirdly attached to my knf un726 also.
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