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Author: Subject: Frozen joints--should I be hopeless?
kyro8008
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[*] posted on 26-7-2009 at 00:19


I know this has already been solved, but I can't believe nobody mentioned the easiest possible solution which (at least for me) works every time.
Just stick the whole thing in the freezer for a while. Sometimes the male connector literally just falls out. If not then gentle twist and it's free.
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12AX7
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[*] posted on 26-7-2009 at 00:47


Quote: Originally posted by kyro8008  
Just stick the whole thing in the freezer for a while. Sometimes the male connector literally just falls out.


Wow, that statement is powerfully Freudian. :D

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bfesser
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[*] posted on 26-7-2009 at 10:56


Well, I had a stuck joint a few days ago; a threaded thermometer adapter in a claisen. The thing wouldn't budge at all with pulling at my full strength. Tried isopropanol, hot/cold water, acetone, root beer--none freed it. I didn't have the heart to waste my precious alcoholic beer. Yesterday, I was a little cranky about something unrelated and picked up the piece, beat the thermo. adapter with a bosshead a few times (pretty damn hard), and it came free. I wouldn't recommend this technique, unless you consider the glassware to be expendable or have the resources to replace it in the event of breakage.

[Edited on 7/26/09 by bfesser]
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[*] posted on 26-7-2009 at 18:36


Maybe this is helpful to someone..

A couple weeks ago I managed to get a stopper stuck in a nearly brand new 3-neck flask (I was pissed!)

So after pulling as hard as I thought safe, I decided to try heating it.. I used an electric heat gun, and tried to heat the outer joint as evenly as possible.. The first attempt failed, I think I heated it too long and allowed the stopper to warm up also, rather than doing it quickly while there is a good temperature differential.. I let it cool off and tried again, this time heating only for maybe 20-30 seconds.. The stopper came right out with a light pull. I was relieved.

If that didn't work, one might try to precool the hole piece (like in a freezer) to get a bigger temperature differential. I'm not sure how much temperature shock it would take though.
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UnintentionalChaos
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[*] posted on 26-7-2009 at 20:32


Quote: Originally posted by kyro8008  
I know this has already been solved, but I can't believe nobody mentioned the easiest possible solution which (at least for me) works every time.
Just stick the whole thing in the freezer for a while. Sometimes the male connector literally just falls out. If not then gentle twist and it's free.


Use your hand on the outside of the joint to generate a nice temperature differential. No need to play with heat guns or torches. Of course, if water has frozen inside the joint, you have other issues.




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1281371269
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[*] posted on 1-11-2009 at 09:50


I recently had a joint freeze - I have no idea why, I think I even had greased it. I put it together to test a setup and a few minutes later couldn't take it apart. I followed this process, trying to get it apart after each step:
Tug at it
Wash it
Use a butane torch to heat up the joint
Apply thick(ish) grease
Apply light grease / penetrative and leave overnight
Boil in sulphuric acid with some H2O2 added (made 500ml of drain cleaner acid dirty, but I was planning to distill it anyway)
Wash
Freeze for a bit
Butane torch
Wash

Then a few minutes later it just popped apart, it was really satisfying :)
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aonomus
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[*] posted on 2-11-2009 at 19:07


The only thing I'd be afraid about when using a torch is leaving it on too long in one spot and heating it up past the softening point (at which point you'd need to re anneal no?).

Well, that and lighting solvents on fire, but who hasn't done that? :D

One thing that I've done was mixed acetone with a bit of vaseline (or joint grease, but vaseline is cheaper), and getting the mixture to wick into the joint. The acetone will eventually evaporate but it should leave the vaseline behind. It worked for saving a round bottom flask before for me.
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12AX7
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[*] posted on 2-11-2009 at 21:04


I've heard that equal parts automatic transmission fluid and lacquer thinner makes a penetrating lubricant on par with the best of commercial products (e.g. PB Blaster). Now, I heard this in regards to rusted metal parts, but it's worth a try on glass, eh?

Tim




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1281371269
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[*] posted on 3-11-2009 at 12:59


A temperature difference is I think the best way - boiling in H2SO4 presumably was only effective in that it provided high temperatures but not high enough to risk damaging the glass. On the other hand, if it had been anything more valuable than adaptors I wouldn't have dared.

How about liquid N2? :D
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[*] posted on 17-3-2010 at 18:17


Quote: Originally posted by jwarr  
I managed to get a teflon thermometer adapter stuck in the ground glass joint of a flask by leaving it in there without lubricant for a long long time.<...> How can I get this to come out easily?

I would like to emphasize that when internal teflon part is involved in a jam (like male adapters/stoppers, stopcocks etc) the ONLY trick that ALWAYS works is the one already suggested by kyro8008:
Quote: Originally posted by kyro8008  
Just stick the whole thing in the freezer for a while. Sometimes the male connector literally just falls out.

And with reason: thermal expansion coefficient of teflon is by the factor of 20 higher than that of Pyrex glass (60-70 vs. 3-4 in/in/F). Needless to say that heating should be avoided when internal teflon fitting is used. Unfortunately, I have learned this only when 29/45 home-maid adapter crushed the joint during distillation :(
As for lubricants, my latest personal favorite is teflon sealing tape, incredibly cheap nowadays.
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[*] posted on 17-3-2010 at 23:54


"Petroleum" has the reputation of getting _everywhere_ ...
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