Stoppers

[Paula]

Hi I am wondering how to get stoppers to fit conical flasks. Is there a way to cut them down to fit? For example I have flasks that need 29.5 mm stoppers and I can only get 29mm stoppers that are just that bit too small. Can anyone help? Thanks

[RosalieM]

Is that the diameter across the top of the flask? I just had a quick look in the Serrata catalogue (first one I laid my hands on) and they have rubber ones that are 32mm across the top, 24 at the base and 28mm high which would probably fit. I don't know about cutting them to size as I would imagine it would be difficult to get it smooth enough to prevent leakages. Someone else might know a way though.
Rosalie

[Paula]

Thanks Rosalie, but the base of the stopper is 29mm. I think the answer will be to get flasks to fit the stoppers!!! Don't like my chances there but thanks. I've looked up all the catalogues etc. The few that I have that fit are from Selbys who are no longer in business.

[Slartibartfast]

If they are rubber - sit them in warm water for a couple of minutes. You will never get a perfect fit if you cut them down.

[lada]

Hi, I have two sizes 32mmx 24mm and 36mmx 30mm. Ask Serrata to send you one of each and try. The smaller one should fit.
Good luck, Lada

[RosalieM]

I am a bit confused... what is the diameter of the flasks you are trying to get stoppers for? The rubber stoppers come in a multitude of sizes. Or are you trying to get the glass ones that just slip in?
Rosalie

[Slartibartfast]

Glass stoppers for a conical flask? That would cost! I would have thought rubber or cork. What are you storing?

[Paula]

I just have a lot of conical flasks that the stoppers are too big or too small for that size mouth. I am preparing a prac that requires tubing into a 1 holed stopper into a 300ml conical flask!!! Confusing I know but I will try try the hot water idea. Thanks everyone, this is a great site, extremely helpful and it's great to see that others have the same quandry's.

[RosalieM]

If across the top of your flask is 29.5mm then any stopper which has a base less than 29.5 and a top of more than that should fit. I would do what Lada suggested and get a couple of samples. It doesn't really help you for this prac but at least you would have them for next year.
Rosalie

[Ocean Breeze]

I Know its a bit too late now, but when I order new conical flasks, I also ask the supply company to send me a bag of stoppers to fit those flasks.
That way, I am not fiddling around with order catalogues and callipers, and possibly recieving an order of bungs that dont fit.Allow the supply comany to do all the work!

I do the same with test tubes, buchner flasks, U-tubes etc. Then note the item numbers for re-order. Even if I think I dont need bungs.. you bet your bottom that somewjere sown the track some experiment will crop up that calls for a bung.

As for now.. I have never had sucess with cutting to fit. There always seems to be a small leak somewhere... so I end up wasting the bung as well as my time

[Mother]

Hi all
I have wrapped glad wrap around the corks to make them fit!!! Works well providing the cork is not too small for the particular glasswear you are using.
Cheers
Mother