evil_lurker
National Hazard
Posts: 767
Registered: 12-3-2005
Location: United States of Elbonia
Member Is Offline
Mood: On the wagon again.
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Flying stoppers...
Don't ya just hate them?
When working with low boiling point stuff with high partial vapor pressures in a closed apparatus... you think everything is all good then next thing
you know the stopper goes flying off and hits the ceiling. 
Ahhh the joys of working in the laboratory.
Not all chemicals are bad. Without chemicals such as hydrogen and oxygen, for example, there would be no way to make water, a vital ingredient in
beer.
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tito-o-mac
Hazard to Others
Posts: 117
Registered: 30-6-2007
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Mood: No Mood
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fit a bigger stopper? maybe try out a flask that has swrew on caps!
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Ozone
International Hazard
Posts: 1269
Registered: 28-7-2005
Location: Good Olde USA
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Mood: Integrated
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Maybe not such a good idea!
Believe me, the stopper flying off can actually save your ass! I have had the side of a 2-L sep-funnel literally pop off (perfectly round piece of
glass) b/c I had inadvertantly frozen the ground glass stopper (and there must have been a small crack in my funnel). This was with diethyl ether at
~28°C.
I always try to avoid "closed-systems"... I like to use a mercury bubbler, manometer or relief valve to keep this stuff straight (a spontaneous
overpressure will give you bubbles, keep your mixture away from air and moisture, and save your precious glass!
And, erm, yes, I have had them hit the ceiling...then fall onto the apparatus and destroy it (heavy glass ones ).
Ever notice that stuff like this tends to happen when someone is watching?
Sucks,
O3
-Anyone who never made a mistake never tried anything new.
--Albert Einstein
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flyingbanana
Harmless
Posts: 38
Registered: 1-3-2005
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makes me appreciate my goggles...imagine if it flew at your eyeballs! Always wear goggles!
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bio2
Hazard to Others
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Registered: 15-1-2005
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....."And, erm, yes, I have had them hit the ceiling...then fall onto the apparatus and destroy it (heavy glass ones"........
A kind of half ass relief valve can be had when using ground
glass pennyhead stoppers by inserting them loosely and tying
a piece of teflon string around them joined to the female joint with a little slack.
That will prevent the falling stopper hazard which is really dangerous. I had a real close call once and it scared the shit out of me contemplating
what could have happened.
For glass stoppers that you really want to stay put use
#18 solid copper wire with 3 or 4 wraps.
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The_Davster
A pnictogen
Posts: 2861
Registered: 18-11-2003
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Mood: .
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Cracked the lightbulb in the hood at work with one. I use ductape to secure them.
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DrP
National Hazard
Posts: 625
Registered: 28-9-2005
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Mood: exothermic
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What about the little plastic clips you get for quick fit joints. They get used to keep stoppers on I think. Good thing is that if there was a really
big pressure increase, I think they would give, allowing the stopper to pop off or at least rise out of the joint a bit to release the pressure.
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YT2095
International Hazard
Posts: 1091
Registered: 31-5-2003
Location: Just left of Europe and down a bit.
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Mood: within Nominal Parameters
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I`ve had it happen with a number 71 gas jar bung before when using my bubbler, you can plug the output and nothing happens for a while, then the pump
starts to change it`s sound then WHUP the bung bounces a good 4 inches.
not in it`self particularly dangerous unless you`re bubbling Cl2 or the likes.
\"In a world full of wonders mankind has managed to invent boredom\" - Death
Twinkies don\'t have a shelf life. They have a half-life! -Caine (a friend of mine)
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tito-o-mac
Hazard to Others
Posts: 117
Registered: 30-6-2007
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How about the one which uses air pressure or suction to secure itself?
You could wear safety glasses or install a barrier of some sort.
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tito-o-mac
Hazard to Others
Posts: 117
Registered: 30-6-2007
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You also try this out just for fun: take a bicycle pump, stuff a cork or stopper at one end and begin pumping. Soon after you will realise it's
getting harder and harder, until you come to a point where there is a short "whoosh" sound and the stopper propels about a good 3-5 metres
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