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Author: Subject: Frozen reagent bottle stopper
Picric-A
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[*] posted on 8-12-2009 at 00:18
Frozen reagent bottle stopper


I have just bough some rather old yet full bottles of Nitrobenzene, Acetic acid and Benzyl acetate all for £3 :)

The problem is they have glass ground joint stoppers and they have frozen. I have tryed tapping but they still wont loosen and i dont want to use too much force on them as smashing them would be a nightmare.

The other problem is i can clearly smell nitrobenzene at the top of the NB bottle and likewise Acetic acid on the acetic bottle.

any tips? wat can i do about the smell and removing the stopper?

thanks,
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len1
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[*] posted on 8-12-2009 at 02:10


Ive had a similar problem at work recently. An old bottle full of chemical, not opened in maybe 40 years. The glass cap had a lip on it, so i inverted the bottle over a bowl (in a hood wearing gloves and glasses of course) and tapped downwards. Now its important how you tap. No force AT ALL must be applied with the hands. I used about 500-800 gm metal bar, which I simply raised a few cm above the bottle lip and let fall on it while holding the bottle with the other hand. This didnt produce much momentum, but the hardness of the glass and metal combine to produce quite a lot force for a very short duration. Then you rotate the bottle a few degrees and repeat procedure.

The bottle opened.

If that hadnt worked my next step would have been to get a diamond tipped glass drill and empty the bottle into a new container through a filter.
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Picric-A
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[*] posted on 8-12-2009 at 02:41


I considered using a penetrating solvent or grease but i dont want to contaminate my 99p bottle of nitrobenzene :P

Do these style of bottles have an airtight seal?
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Arrhenius
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[*] posted on 8-12-2009 at 08:01


All of those solvents are high bp. Heat the outside of the joint <i>quickly</i> with a heat gun and then remove the stopper. Don't tap glass with metal... you're bound to break it. Wood is maybe a little better, but Ideally don't hit any glassware with anything.. haha.

http://www.sciencemadness.org/talk/viewthread.php?tid=12383

[Edited on 8-12-2009 by Arrhenius]
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Picric-A
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[*] posted on 8-12-2009 at 08:48


I have tried the wooden tapping with no success...
i was just rightly scared to heat a bottle of nitrobenzene :P
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stateofhack
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[*] posted on 8-12-2009 at 09:47


Use your teeth :D
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len1
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[*] posted on 8-12-2009 at 10:37


Wood has a low youngs-modulus, which means you dont nearly attain the same instanteneous force with it for the same momentum as with metal. With experience you learn how to tap properly, ive never had a cap broken.

On the other hand thermal shock I find works well only recently seized joints because the conductivity of a well-seized joint is normally too good. Heating a bottle full of solvent with a low flash point with a heat gun is also dangerous. Should it burst due to internal pressure or uneven heating -bottles are not designed to take heat-stress - you can have a fireball on your hands, so I dont do it.

[Edited on 8-12-2009 by len1]
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Picric-A
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[*] posted on 8-12-2009 at 10:56


Quote: Originally posted by stateofhack  
Use your teeth :D


might give it a shot :P jks
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[*] posted on 10-12-2009 at 05:17


You can cool the stopper either ice or liquid nitrogen. This will contract the stopper and can effectively losens the stopper many a times. use cotton glowses or cloth while handling to protect the hands.
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[*] posted on 12-12-2009 at 06:13


I managed to open both stopper.
I applied some WD40 to the stopper and left for 10 mins to seep in whilst gradually rocking the stopper to help the oil seep in.
After 10 mins of being left in a cool enviroment i heated the socked quickly with a NiCr wire spun around it. This enabled the stopper to be removed easily.

The bottles are not fine and the stoppers are wrapped in PTFE tape.
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