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Author: Subject: Frozen joints--should I be hopeless?
querjek
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[*] posted on 16-6-2009 at 18:40
Frozen joints--should I be hopeless?


I found a very nice Friedrich condenser recently with one problem: there is a male joint piece frozen in the upper joint. I've tried an H2SO4/H2O soak and a naptha soak so far, and though the naptha appears to have saturated most of the area between the two, there is a white patch which hasn't changed in the last two days.

I was thinking of doing a base soak, but didn't want to damage the glass. I've also tried running it under hot water, but that was pretty hopeless in the first place.

I've search for past topics here and have found a few suggestions for solvents, but does anybody here have any experience or advice in the area?

Thanks!




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bfesser
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[*] posted on 16-6-2009 at 20:39


Would it be possible to get a picture?
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UnintentionalChaos
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[*] posted on 16-6-2009 at 21:41


hot acetone has some impressive penetrating and solvating power.
You could try "gentle" percussive repair in the wort case scenario ;)




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kclo4
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[*] posted on 16-6-2009 at 22:03


Perhaps add a lubricant in the hot acetone, if the hot acetone doesn't work at first? I have loosened joints using glycerol alone, and with ones sealed shut from making S2Cl2 hot toluene works well.



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Arrhenius
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[*] posted on 16-6-2009 at 22:03


You need to get a torch or heat gun on it. Quickly heat up the outer joint, and it should come free. Works almost every time. Just don't do it with a flask full of solvent! :D
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merrlin
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[*] posted on 16-6-2009 at 22:17


Quote: Originally posted by Arrhenius  
You need to get a torch or heat gun on it. Quickly heat up the outer joint, and it should come free. Works almost every time. Just don't do it with a flask full of solvent! :D


That should work. If it doesn't, try blowing a water mist through the connection before and during the application of the heat source. It will increase the differential expansion and making timing less critical.
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panziandi
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[*] posted on 17-6-2009 at 03:40


WD40 sprayed around the joint, seeps into the joint. Then quickly heat the joint evenly and then try pulling apart, sometimes worth trying a twist then a pull.



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entropy51
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[*] posted on 17-6-2009 at 05:58


All the above sometimes work, but for the novelty of it nothing beats a suggestion that was published in J Chem Ed: soak the joint in carbonated beverage. Supposedly the tiny bubbles can penetrate the joint and help free it.

This actually worked for me once. Sometime I'm going to try it with beer instead of soda.:D
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bfesser
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[*] posted on 17-6-2009 at 11:42


Now I'm tempted to purposely freeze a joint and throw it in a beer just to see if it works. If it were feasible to get a consistently stuck joint, it would be fun to compare beers, say a Guinness to a Red Stripe.

What is the male joint peice? If it's expendible, score it up a bit and carefully break it out.
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Eclectic
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[*] posted on 17-6-2009 at 12:39


Ultrasonic cleaning baths sometimes work.
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hissingnoise
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[*] posted on 17-6-2009 at 12:50


Or as a last recourse, a good vibrator (wog's) taped to the condenser.
A sustained pull on the male joint with the vibrator on just might work. . .
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[*] posted on 17-6-2009 at 13:31


And should you have to tap it with something, use wooden tools. They don't break glass as easily.



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[*] posted on 18-6-2009 at 05:05


Quote: Originally posted by bfesser  
Now I'm tempted to purposely freeze a joint and throw it in a beer just to see if it works. If it were feasible to get a consistently stuck joint, it would be fun to compare beers, say a Guinness to a Red Stripe.

And you won't need the whole can for the experiment. You'd have to find SOME way to dispose of the excess.
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BromicAcid
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[*] posted on 18-6-2009 at 14:56


Does the male joint have anything to grab onto? Is it broken off in there or is it some kind of adaptor. In many cases additional leverage can rectify the error, just be sure to wear cut resistant gloves. Wrap the area with silicone tape for extra grip so you can really torque on it. Applying heat, be it with a heat gun or nicrome wire also helps as others have mentioned. Base baths don't do well for frozen joints and can make the problem worse, they are best for cleaning up stuck on gunk and the like.

Push come to shove you can always carefully use a pair of plyers to break into the piece stuck in the joint then use a screwdriver to break it out in pieces. Although some people consider it taboo, you can carefully use a pair of vice grips or other tools on the glassware to get a better grip. Every time you risk the glassware, but if you wrap it in silicone tape first the risk is not as great, but it is usually only in dire circumstances that you would do such a thing (except with some of the stoppers I use which are flat at the top, I use tools on those quite a bit).




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[*] posted on 19-6-2009 at 09:24


Hair drier works too.



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[*] posted on 20-6-2009 at 09:03
some suggestions from the Journal of Chemical Education


here are some suggestions from the Journal of Chemical Education

----If the bottle chances to contain a small amount of the solution the stopper can sometimes be removed by inverting and so causing the contents to act as solvent

--A frozen ground glass joint can often be freed by warming the joint to a temperature above the melting point of beeswax (about 65"C), applying the wax around the lip and allowing it to
cool. The wax melts and penetrates the joint as it coals. Slight reheating will allow the d i sassembly of the joint. An alternate procedure is to dip the frozen joint (for example, a buret
stopcock) into a bath of melted beeswax. Residual wax can be cleared off the glassware by using warm (about 75°C) xylenes. The glassware either can be dipped into a xylene bath, or the solvent applied warm with a towel.

--heating the external part of the joint, oftrn results in breakage
tosoak the joint in a carbonated soft drink. The joint usually separates in five minutes or less

-- vacuum pump oil is placed on the joint. In a few minutes to a half hour the joint has loosened. Sometimes soaking in hot water is necessary

hope these help

there is also a few suggestions on how to avoid stuck joints but thats another story.....hahhaha

oh yeah one other item - if all fails place the flask on a holding shelf because tomorrow is another promising day........gulp!

[Edited on 20-6-2009 by jimwig]




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[*] posted on 20-6-2009 at 12:09


can you get the frozen part into an ultrasound bath? This has worked for me when all else failed



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benzylchloride1
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[*] posted on 20-6-2009 at 19:26


I almost always use a propane torch on frozen joints unless a flammable material is present. A side note on teflon stoppers, teflon stoppers expand greatly when heated and have to be cooled in a stream of cold water for several minutes before they can be removed. I had several joints freeze today during a chloroacetic acid synthesis. I used silicone grease on all of the joints. The joints on the chlorine generator froze and a was able to get them apart using a torch. The chlorine had turned the silicone grease into a white solid that was difficult to remove. Apparatus should be disassembled promptly after a reaction, and grease should always be used when bases are being used in ground glass apparatus. I broke an Allihn condenser by trying to separate it from a flask after it had been used in a basic hydrolysis.



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[*] posted on 22-6-2009 at 23:36


Bases can lock up joints so they are damned hard to move. Still, they usually can be separated.......eventually. If you don't get frustrated and break things.

If all else fails, and you don't need to use the glassware immediately, take the long view. Spend a minute or so each day, gently trying to separate the components, then go do something else.

One day you will pick up the stuck apparatus, absentmindedly give it a gentle twist, and slicker than owl shit, it will simply come apart, as if it had never been locked up at all.
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[*] posted on 24-6-2009 at 03:46


I recommend Bredemann's solution:

10 parts of chloral hydrate
5 parts of glycerol
5 parts of water
3 parts of 25% HCl

All parts are per mass of course.

Should work. If this does not help, only torch will help.
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[*] posted on 24-6-2009 at 06:30


Thanks for all of the suggestions--I've been in and out of town for the last week but have tried to change my soaking solvent each time I've been home.

I've done two H2SO4 soaks and two naptha soaks. The joint appears to have liquid flowing around most of it now.


Regarding Bredemann's solution--I have no access to chloral hydrate and wouldn't want to waste the chemicals to make a sufficient amount of it for what what I'm doing. What could I use to replace this, if anything?




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[*] posted on 24-6-2009 at 07:55


If you remove chloral hydrate, it will be no Bredemann's solution

Soaking in H2SO4 and naphtha helps to wet the connection? Gentle moving of the male piece against female should help, if there's enough hulk raising above of course.

If the male part sits deeply in the female one... try running hot water, but for many hours.

All this may not be able to help - I had such cases. They are still kept somewhere in my lab; who the hell knows, when I try them next time - and may be with success...
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[*] posted on 24-6-2009 at 20:48


@benzylchloride1- I've been afraid to get very active with a propane torch. The concern has always been differential heating. Have you always been able to flame them apart without breaking either one?



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[*] posted on 24-6-2009 at 22:36


Quote: Originally posted by chemrox  
@benzylchloride1- I've been afraid to get very active with a propane torch. The concern has always been differential heating. Have you always been able to flame them apart without breaking either one?


I have been able to do it, but I've always been deathly afraid of breaking it so I've been very careful and I didn't heat it to very high temperatures.




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querjek
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[*] posted on 29-6-2009 at 17:05


Well, today I decided to take the condenser out of a mixture of isopropyl alcohol, sulfuric acid, and water.

I rinsed it with water and dried it. I knew I couldn't twist it, so I tried rocking it back and forth--click--it came out. Easy as that.

Overall process--soaks in:
-H2SO4
-naptha
-naptha
-H2SO4
-iPrOH, followed by some H2SO4 (it heated itself, possibly producing acetone?), followed by water

Yay. Thanks for the advice, everyone!




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