MattVon - 25-7-2012 at 15:29
I brought some new glassware and their stoppers, and I ran into a little trouble. I was sort of in a hurry
and I stuck a stopper that is just a little too small into a round bottom flask, and it got stuck. I used some random blunt tools I had to knock the
stopper loose, and it fell into the flask.
Normally, I used a handkerchief and use a trick to pull out stuck rubber stoppers, but this one was different. The stopper refused to come out, and I
even tried boiling it in water, and stabbing it with a knife.
It got a little sliced up, but still remained in one big piece and its now just in the flask, rattling around. I don't have much chemicals on hand,
and the strongest acid I have is sulfuric. But I had heard that sulfuric acid turns rubber rock hard, so I don't think I'll be using that anything
soon.
Now, I'm ending up with a 500ml round bottom flask, with a size 6 stopper rattling around inside it. How can you ever get the stopper out of it? It's
a black rubber stopper, if you need to know it.
Mailinmypocket - 25-7-2012 at 15:52
I have had luck using a really long floor screw... I stabbed it into the cork and then screwed it into it and pulled it out gently. Not very reliable
though because the screw can easily slip out
Endimion17 - 25-7-2012 at 16:11
Heat a knife or a thick steel wire in a flame until it's red hot and destroy the stopper like it's a block of butter. Even better, push the wire into
the stopper, let it cool, pick it up and use another wire to slice it in mid air, inside the flask. Be careful not to touch the glass with the glowing
metal and avoid smearing the molten rubber because that's kind of hard to clean up.
MR AZIDE - 25-7-2012 at 16:14
I can remember once having an organic solvent, in a flask that was stoppered, ( cannot remember what the solvent was., but the botton of the stopper
seemed to dissolve, and go kinda pasty, and was able to be pulled apart like a very thick sticky liquid.
A solvent like hexane got absorbed into the stopper, and the stopper can swell up in the neck of the flask, and be tight to pull out, the stopper
remaining swollen up , once clear of the neck of the flask.
[Edited on 26-7-2012 by MR AZIDE]
hissingnoise - 26-7-2012 at 01:39
You could try filling the flask with water, stoppering it with your hand, inverting it and maneuvering the stopper into the neck.
Then, carefully heat the flask with a hair-dryer (a heat gun might crack the glass) and the increased internal pressure might pop the stopper.
Pyro - 26-7-2012 at 03:00
nitric acid might do,
how about xylene? i have used it as a paint thinner, and it dissolves almost everything. varnish, latex, vynyl, and over a while nitrile.
Pyro - 26-7-2012 at 03:04
nitric acid might do,
how about xylene? i have used it as a paint thinner, and it dissolves almost everything. varnish, latex, vynyl, and over a while nitrile.
but why on earth you pushed it into the flask in the first place i don't understand.
why didn't you think of doing what the (im not sure who? french probably) did hundreds of years ago? it a little metal spiral for pulling corks out of
wine bottles. YES thats right, a cork screw 
nitric acid would probably be best