vulture
Forum Gatekeeper
Posts: 3330
Registered: 25-5-2002
Location: France
Member Is Offline
Mood: No Mood
|
|
Separatory funnel
I've got a rather annoying problem with my separatory funnel. When I filled it with acetone the valve leaked a few drops but that stopped very
quickly.
When I wanted to drain off some acetone I noticed the valve got stuck. There is no way to turn it.
Anybody got a nifty suggestion?
One shouldn't accept or resort to the mutilation of science to appease the mentally impaired.
|
|
|
madscientist
National Hazard
Posts: 962
Registered: 19-5-2002
Location: American Midwest
Member Is Offline
Mood: pyrophoric
|
|
I've had the valve of my separatory funnel get stuck before, and I found that I can free it by pushing the rotating knob sideways (instead of
trying desperately to rotate it).
I weep at the sight of flaming acetic anhydride.
|
|
|
vulture
Forum Gatekeeper
Posts: 3330
Registered: 25-5-2002
Location: France
Member Is Offline
Mood: No Mood
|
|
Well, that didn't work.
The lab head at my university suggested carefully heating it above a bunsenburner, that's what they always do.
One shouldn't accept or resort to the mutilation of science to appease the mentally impaired.
|
|
|
CherrieBaby
Hazard to Self
Posts: 91
Registered: 4-3-2005
Location: London
Member Is Offline
Mood: No Mood
|
|
You have to heat the funnel but not the tap. In practice you can't do that but you should be able to have the funnel get more heat than the tap.
They sometimes suggest putting it under a hot water tap.
|
|
|
Darkblade48
Hazard to Others
Posts: 411
Registered: 27-3-2005
Location: Canada
Member Is Offline
Mood: No Mood
|
|
Errr, wasn't this thread like 2 years old? I think vulture would have figured it out by now 
But I did learn that you could use a bunsen burner flame to undo stuck valves 
|
|
|
aldol
Harmless
Posts: 30
Registered: 7-3-2005
Member Is Offline
Mood: No Mood
|
|
sep funnell
instead of using it dry you should be taking the tap out each time cleaning it and coating it with tefflon . or vasaline
make shaw you dont coat it in line with the holes . above or below the holes !
This will stop your leaks as well
|
|
|
CherrieBaby
Hazard to Self
Posts: 91
Registered: 4-3-2005
Location: London
Member Is Offline
Mood: No Mood
|
|
The other thing you can do is spray it with WD 40 and leave it for 10 minutes then try again.
|
|
|
mick
Hazard to Others
Posts: 338
Registered: 3-10-2003
Member Is Offline
Mood: No Mood
|
|
It has probably been mentioned before but a quick summary.
Glass on glass can some times be shifted with heat unless contaminated with alkali and then low heat just seems to fuses them together.
Annelling temperature might work.
PTFE on glass is temperature sensitive. The expansion coefficients are different. PTFE can seize in a glass barrel over 40-50oC temperature rise
unless checked or will become loose at low temperatures.
A top quality glass tap with a smidging of the right lubricant should work. Silcone OK for water, paraffin wax is OK for nBuLi in hexane because there
is no real contamination but it needs topping up.
Wet and dry sanding paper with WD40 can be used to lap a glass tap in.
mick
|
|
|
aldol
Harmless
Posts: 30
Registered: 7-3-2005
Member Is Offline
Mood: No Mood
|
|
sep funnell
you could take it to a glass blower and they will fit a hole new tap fairly cheap .
depending on what the funnell is worth
also they will proberly ask you what has been in it .
personly i would not use a sep funnell with a glass tap mine has a teflon tap they are great .
mine has also had a new tap fitted
but i have a freind that worked at a uni for thirty years as a glass blower .
a genius to watch
regards aldol
|
|
|
![[*]](images/xpblue/default_icon.gif){kind=icon}
