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LD5050
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Unfreezing glass joints?
I have a problem, the glass thermometer adaptor is now stuck to my glass distillation head adaptor and I can't remove them from each other. Usually if
this happens I lightly heat the joints with a butane torch and they will come apart but this one is being stubborn. Any ideas on how to get them
apart? What do some of you do in this situation?
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100PercentChemistry
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Place in boiling water for awhile and then cool it in the freezer? The water might help to get in between the cracks and then the
expansion/contraction during the heat change might pry them apart. I haven't tested this though.
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Chemetix
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WD40, a bit of heating and cooling, and a bit of tapping with a wooden dowel. Glass is slightly elastic, the tapping can bounce apart the point of
friction that is holding the joint shut. The WD40 is a good lubricant which eventually penetrates between the closest of joins.
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j_sum1
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Chemetix is a glass worker. I'd take his advice on this one.
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LD5050
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Awesome thank you chemetix only thing is I don't have any w-d40 so my next question is how do I synthesize it..? Ha kiddingg
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Magpie
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1. Try rapping with wood dowel.
2. Cool inner piece with ice water, solid CO2 in acetone, or liquid N2. Then heat outer piece with boiling water, silicone oil, or heat with torch
and quickly twist.
Let us know what works.
[Edited on 10-10-2017 by Magpie]
The single most important condition for a successful synthesis is good mixing - Nicodem
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JJay
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I've had this happen before. Usually hot water and tapping with a rod is enough to get them unstuck, but if you were using high temperatures when they
got stuck, you might have to use a blowtorch.
Disclaimer: I broke an expensive Kontes distillation adapter yesterday with my bare hands when trying to remove the thermometer adapter from it. Don't
use too much force.
[Edited on 10-10-2017 by JJay]
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DrP
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I'll second/third the tapping/heating suggestions..
..with regard to the lubricant, if the heat and vibration do not work, I seem to remember a soak in a base bath can make things really slippery... I
do not know if a good long soak in a base bath will help or not - might be worth a try if nothing else works. It would take time to work its way into
the joint probably, but could help.
\"It\'s a man\'s obligation to stick his boneration in a women\'s separation; this sort of penetration will increase the population of the younger
generation\" - Eric Cartman
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JJay
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I managed to melt a clip over a joint yesterday, causing the joint to freeze, and separated it by simply scraping off the molten clip, running hot
water over the joint, and tapping it with a stir rod while periodically trying to rotate the joint. A base bath will make some substances slippery but
can make things worse with frozen joints; I definitely don't suggest it.
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DrP
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Quote: Originally posted by JJay  | | A base bath will make some substances slippery but can make things worse with frozen joints; I definitely don't suggest it. |
OK - thanks.... I was suggesting it as a last resort if all else fails really.
\"It\'s a man\'s obligation to stick his boneration in a women\'s separation; this sort of penetration will increase the population of the younger
generation\" - Eric Cartman
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VSEPR_VOID
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| Quote: Originally posted by Magpie | 1. Try rapping with wood dowel.
2. Cool inner piece with ice water, solid CO2 in acetone, or liquid N2. Then heat outer piece with boiling water, silicone oil, or heat with torch
and quickly twist.
Let us know what works.
[Edited on 10-10-2017 by Magpie] |
Is there a danger of thermal shock using solid CO2 in acetone to unfreeze glass joints?
Within cells interlinked
Within cells interlinked
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LearnedAmateur
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I know it doesn't help you with this issue, but for the future, it's good practice to lightly grease (at least) the male joint - petroleum jelly is
perfect for this as it is quite inert, and can be found cheaply and commonly. Not only does it help with separating the joints, but it creates a
better seal so gases and such are less likely to leak, quite common during reflux and distillation, I find.
In chemistry, sometimes the solution is the problem.
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NEMO-Chemistry
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Again for the future, i got sick of pet jelly dripping into reactions etc, i got sick of frozen joints and breaking new bits of glassware. In the end
with a heavy heart i splashed out on the dow corning high temp vac grease. i tend to over use the amounts but i got to say its been worth every penny.
maybe i am heavy handed with pet jelly, but with me it just melted and got into everything, at least the dow stuff dosnt seem to do that, be warned
its a bitch to clean off though
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Texium
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A paper towel with hexanes or petroleum ether will easily remove high vacuum grease if you're having trouble with that. I still don't often grease
joints though to avoid contamination and make cleanup easier. I've never had one break on me as long as I've gotten the apparatus taken apart
immediately after being finished with it.
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NEMO-Chemistry
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| Quote: Originally posted by zts16 | | A paper towel with hexanes or petroleum ether will easily remove high vacuum grease if you're having trouble with that. I still don't often grease
joints though to avoid contamination and make cleanup easier. I've never had one break on me as long as I've gotten the apparatus taken apart
immediately after being finished with it. |
Great tip thx, both solvents mentioned are about the only two i havnt thrown at it!! typical  .
I finally found a reasonable priced supply of hexane as well.
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SWIM
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Some pro here, I believe it was Woelen, recommended wetting the joints with the solvent used in the reaction if you don't want to, or can't, use
grease.
I've tried it since then, and it works pretty well for sealing and lubricating joints.
I still use High vac grease for very high temps.
Vaseline (petroleum jelly) works for some things, but there's a certain temperature (different with different brands probably) where it gets too thin
and runs out of some joints.
It's worth pointing out here that there are tight joints and there are TIGHT JOINTS.
Some glassware (usually better brands; the big domestic and European makers and a few of the best Chinese companies like Laboy) seems to have tighter,
smoother joints than others.
These need less grease and are also less likely to seize in my experience. If you assembly the joint clean and dry and rotate it slightly you can feel
the difference in that it's smoother to turn.
I have used a very light grinding with toothpaste to make low budget glassware less likely to stick.
It can be done without ruining the universality of fit if you only do a VERY light grinding.
I think it just takes off the tips of very tiny high points from the factory grind being too coarse.
Maybe this last is not as good an idea as I believe it to be, and I welcome any comment as many here probably know better than I.
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Magpie
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I just freed a very tight 24/40 joint of an adapter with a Chemglass 250ml rbf.
I had sealed the joint with con H2SO4 only. But I had made oleum and I supposed some HPO3 had penetrated the joint. I tried ice water in the rbf to
expand the outer plus propane torch on the inner to shrink it. I realize now that this is the opposite of what I should have done!
Concludeing it was a chemical fusion with the glass I poured acetone on the joint then rapped the neck on the ss sink edge. I then twisted wheupon I
detected a slight slip. Twisting again it broke it loose.
The single most important condition for a successful synthesis is good mixing - Nicodem
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diddi
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WD40 for me. even if it takes a few days to soak in, it works every time. Scored a lovely condensor because the previous owner could not get it apart
and couldnt be bothered trying the WD 
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Chemetix
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For a final endorsement for the ol' WD, I found it takes off silicon grease like a charm as well. If hexane isn't at hand. And SWIM has a good point
about giving a fine polish to the joint, and I'd say you are on the money with not getting carried away with the polish and loosing the
interchangeability.
I have some silica flour (Inhalation hazard!) that I use with water as an abrasive for fine grinding borosilicate glass joints, which are indeed less
prone to seizing once polished a bit than a rougher joint.
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LD5050
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So I tried using wd-40 letting it sit for a few days heating etc. and I still couldn't get it to budge. So I then got some crushed ice and filled the
inner joint with ice and water and heated outer joint with torch like magic it came apart like it was never stuck.
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DrP
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| Quote: Originally posted by NEMO-Chemistry | Again for the future, i got sick of pet jelly dripping into reactions etc, i got sick of frozen joints and breaking new bits of glassware. In the end
with a heavy heart i splashed out on the dow corning high temp vac grease. i tend to over use the amounts but i got to say its been worth every penny.
maybe i am heavy handed with pet jelly, but with me it just melted and got into everything, at least the dow stuff dosnt seem to do that, be warned
its a bitch to clean off though |
Haven't had to use them for years - but you are right... maybe you put too much on. What about PTFE tape? That can seal the join without it
sticking and it won't drip...
\"It\'s a man\'s obligation to stick his boneration in a women\'s separation; this sort of penetration will increase the population of the younger
generation\" - Eric Cartman
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PirateDocBrown
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Don't get too rough with it.
Don't be afraid to set it down, and try again another day. It's amazing how it can change on a second or third try.
Hot water and a fridge have always worked for me.
I do use very light silicone grease on most joints.
Phlogiston manufacturer/supplier.
For all your phlogiston needs.
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ninhydric1
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Silicone grease is the my preferred method for greasing joints. If a joint gets stuck, I just use heat a little bit of tapping of the inserted joint.
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LD5050
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I read di electric grease has the same ingredients as Corning high temp grease. So I bought some of the di electric grease and it works great.
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Dr.Bob
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I have had luck on some joints with a sonicator. If you fill the entire flask or item and sonicate the daylights out of it, an hour or two day over
a few days, sometimes it will just pop apart with enough shaking. I have had 50% success of late with that trick. Next step is heating the outer
joint with a torch on the two that failed to come apart. After that comes the hammer...
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j_sum1
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