Vac filtration tip

[homeslice]

Maybe someone posted this before but i doubt it.

Usually swim does his vac filtrations by just setting the buchner on top of the glass flask without any sealent and it takes a little while. Like 10 minutes as opposed to a long long time without any vacuum. So this last time swim tried something a little different. He took a piece of saran wrap,  like 1 foot square and cut a slit in the middle of it for the buchner to fit through, then placed the whole thing on top of the flask. Then he wraps up the rest of the saran wrap around on the seal to seal it up good. Just figured id share  

[wolfx]

Why don't you just buy a rubber adapter instead ? The best one, in my opinion, is the kind that fits permanently in the bottom of the bucher funnel. When you place the funnel atop the filtering flask it forms a tight seal.

Another kind is a flat rubber disk, with a hole with conic edges, just place it atop the filtering flask and the bucher fits exactly over the hole, also forms a good seal.

I have two different sized bucher funnel, one kind for each, both work fine.

[methyl_ethyl]

These tend to work better,  







EDIT Sorry Wolf, ya beat me by a minute..  

[wolfx]

The one that methyl_ethyl pictured at left is the one I mentioned first. They come in different sizes, has to fit bucher funnel exactly, but will fit slightly different size flasks ( but not too big, not too large ).

A third type is the one in the right, stopper style, same comments. Has to fit exactly ( or closer ) both funnel and flask.

The flat rubber disk ( second kind I have mentioned) fits more varied sizes of funnels and filtering flasks and is also cheaper. Only requirement, has to cover filtering flask mouth ( quite large, will fit many sizes ) and the tip of the funnel has to be small enough to pass through the center hole.