Phosgenetimemachine
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looking for a stopcock swap?...?..
OK...A while back i suddenly came to need a decent sized sep funnel,after the last one suffered the usual fate....Anyhow although a 2000 was ideal my
60ml budget was less than...long story short i came across a very reasonable deal on ten 250 ml 6402 pyrex,so i purchased them knowing I would be
separating in less volume more times...no big deal...well about then i realized there were no stopcocks....damn...What I DO have are a number of brand
new,unused ptfe 4MM,and probly twice that many 2MM,what i need are one or more NUMBER 4 stopcocks,i will gladly swap two for one,hell if you have use
I will probable sweeten it because at the moment i have no use for either 2 or 4 ml stopcocks,oh i also have a couple used glass stopcocks, i will
take either ptfe or glass and really i"ll give those i have to whoever needs 'em
[Edited on 26-1-2018 by Phosgenetimemachine]
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Dr.Bob
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Are these sep funnels designed for glass or PTFE stopcocks originally? If they are for PTFE stopcocks, the stopcock receiver will be smooth, clear
and transparent glass. If they are designed for glass stopcocks, which are commonly labelled #2 or #4, then the joint will be translucent and etched
looking, as it was ground, not molded. These are not interchangable, so if you have the ground glass type, you cannot use PTFE stopcocks, unless
you can find one fo the few ones that was made by Kontes years ago, but they did not work well, as the coefficient of expansion of the two materials
is different, and the glass ones are not designed to work with PTFE's properties.
PTFE type stopcock ground glass type stopcock
 
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Phosgenetimemachine
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Thank you for the enlightenment,it is much appreciated.Im afraid that they are the ground seat,and I did not in fact get such a bargain.
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Dr.Bob
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Glass stopcocks are not perfect, but they work fine, I would just use them with the glass stopcocks and a little grease, and they will work. They do
last a long time, whereas PTFE stopcocks can get scored, warped, or damaged easily. I would just use them until you can save up to afford to get the
2L one you want. Then you can save them for smaller reactions, maybe sell a few on Ebay one at a time, just make it clear that they are glass
stopcock ones. You also might be able to sell a few here.
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