Sciencemadness Discussion Board

Quick Question: Buchner funnel size

Sulaiman - 6-12-2015 at 03:05

For filtering I just ordered 250 ml Buchner/conical with side arm flasks.
(could not resist 4x 250ml boro3.3 £6.99 incl. p&p whilst browsing)
90mm diameter papers are suitable and seem the most common,
eBay vendors do not all give clear dimensions,
so,

What outside diameter porcelain Buchner funnel is suitable for 90 mm diameter filter papers ?

Edit, I have looked a little, 110 mm o.d. is my current guess
and it should have been 'Approximately what outside ..

[Edited on 6-12-2015 by Sulaiman]

ave369 - 6-12-2015 at 04:07

My own Buchner funnel is a 60 mm, and I cut out the paper circles myself. A 120 mm filter paper circle makes four custom circles.

Sulaiman - 6-12-2015 at 07:13

so for your 60 mm funnel (i.d., o.d., ?) what diameter circles do you cut ?

Deathunter88 - 6-12-2015 at 08:12

Quote: Originally posted by Sulaiman  
For filtering I just ordered 250 ml Buchner/conical with side arm flasks.
(could not resist 4x 250ml boro3.3 £6.99 incl. p&p whilst browsing)
90mm diameter papers are suitable and seem the most common,
eBay vendors do not all give clear dimensions,
so,

What outside diameter porcelain Buchner funnel is suitable for 90 mm diameter filter papers ?

Edit, I have looked a little, 110 mm o.d. is my current guess
and it should have been 'Approximately what outside ..

[Edited on 6-12-2015 by Sulaiman]


Remember that the filter paper should be 10mm smaller than your funnel. 100mm funnel, 90mm paper.
As a result, 90mm filter, 100mm funnel.

Dr.Bob - 6-12-2015 at 16:05

Coors lists their Buchner funnels by the ID (filter paper size), not by volume or OD. The exact difference between the ID and OD varies, as they are thicker with larger sizes. If someone lists one without the ID or filter paper size, you should just send them a note and ask them for the filter paper size.


AvBaeyer - 6-12-2015 at 19:30

You may find this generally helpful which was easily found on the web.

AvB

Attachment: Buchner-Funnel_Dimensions Coors.pdf (475kB)
This file has been downloaded 497 times

ave369 - 7-12-2015 at 09:03

I fold a 120 mm filter paper circle in four, take scissors and round all the edges. As a result, I get four little circles that fit my Buchner.