Rubber stoppers gone hard!

[Labbie]

Morning Folks,

I have found, in the back of our cupboards, some very old, but ok rubber stoppers, but they are very hard indeed. Has any one else had this problem. Any ideas how to get them soft again.


Thank you

[ri]

Hi Sue,
I have had the same discovery at the backs of cupboards.
I used to discard them but really should keep them for when they need a surface to hit tuning forks on and to attach to string for those rotation experiments, etc.
They have no use as the original intention as stoppers anymore and I don't know of a method of softening them. They are not cheap so I can understand you wanting to try.
Good Luck!
~Robyn

[Lyn]

Hi Sue,
Once upon a time I used to try and recycle dead rubber stoppers. Packaging tape wraparound, shaving thin slices off using single edge blades, etc. The realisation eventually set in that I was flogging a very dead horse and that the commonsense thing to do was to bin them. Show no mercy.
Lyn.

P.S. I kept the three inch wide stoppers for the tuning forks.

[Slartibartfast]

Automatic transmission fluid - 400mls with 100mls of metho and leave to soak overnight. Glycerin also works well if not AzNu from plumbers rejuvinates rubber washers and works a treat on rubber bungs (drag racers use it to soften tyres before a race)

[Labbie]

Good one Richard, Thank you so much. I shall get some, and soak over the long weekend.

Cheers

[Ocean Breeze]

well, there you go! Clever. Thanks Richard
RS

[Labbie]

I finally got around to doing the Rubber stoppers, and would like to say they did come so very well. Well worth it all. Not quite back to new, but nice and soft.

Well Done Richard

[Ocean Breeze]

I have a numbe rof rubber bungs.. one and two holed that fit my equipment/glassware perfectly.
After much use and years, they had gone hard, shiny due to oxidation...and wouldnt stay in the neck of the glass boiling flasks anymore. ( kept popping off)

Rather than throw them out, I have "restored" them.

This involved using some rough emery paper to scour the outside of the bung.. evenly all the way around.
Then a quick wash to remove the dust.
Dry well.
Then I wiped them with butan-2-ol. seems to work really well, and they have comne up like new.. I decided to use the butan-2 -ol , as I wanted a hydrocarbon that wasnt oily, but not metho or ethanol.

I will be really interssted in finding a better way to resore bungs.

What do you guys do/use?

[Ocean Breeze]

yes
they get all hard, shiny and oxidised. Then they just wont stay in the neck of a flask, keep popping out.