# Filtering and filter paper for visual learners



## patnor1011 (May 29, 2011)

Just couple pictures I thought might help.


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## Harold_V (May 29, 2011)

Patnor,
That's an interesting article. 

The funnels I used in my processing days were made by Nalgene, and intended to use round filter paper. I expect the included angle was 60°, although I am not sure. In order to achieve a proper fit, the paper was folded in half, then in half once again, so 90° of the circle remained. The paper was then opened, with three layers on one fourth of the circle, and the balance a single layer. I suspect the approximate 10° noted is for use with funnels of a different included angle.

I'm curious about the recommendation to tear off the corner. To my knowledge, it serves no purpose and offers the threat of overflowing fluid past the filter paper. Do note that I had a secure setup and often filled my funnels to the top, disregarding the admonition to fill them only 2/3 full. The top third holds a huge amount of fluid, so it bought me time in my extensive filtering operation. 

Harold


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## rmi2416 (May 29, 2011)

Is there a big difference in filter paper vrs. say coffee filters? I have only used coffee filters so far and was wondering if moving to filter paper would make a difference?


Best Regards,
Ross


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## samuel-a (May 29, 2011)

rmi2416 said:


> Is there a big difference in filter paper vrs. say coffee filters?



Finer solids will cought in the filter paper, this is what they are designed for...
Depends of course on the grade you are buying.


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## Palladium (May 29, 2011)

Coffee filters i have found range from 5 - 25 microns on the average.
I've been doing some research on my fizzer cell which needs a pore size of .5 microns to work. Understanding particle size i have found is a very interesting topic to research. As far as what type filters are best for what application i couldn’t tell you. The other members can help you there. Just wanted to give you a starting point to help you answer your question.

http://www.gewater.com/pdf/spec2.pdf 

http://clearstreamfilters.com/micron.htm


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## rmi2416 (May 29, 2011)

So for say AP washing and what not Coffee filters are fine I would guess. I haven't had any problems yet but now I am worried


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## qst42know (May 29, 2011)

Palladium said:


> Coffee filters i have found range from 5 - 25 microns on the average.
> I've been doing some research on my fizzer cell which needs a pore size of .5 microns to work. Understanding particle size i have found is a very interesting topic to research. As far as what type filters are best for what application i couldn’t tell you. The other members can help you there. Just wanted to give you a starting point to help you answer your question.
> 
> http://www.gewater.com/pdf/spec2.pdf
> ...



Many of these techniques like a Wholwhill gold cell or perhaps even a fizzer cell predate poly floss or borosilicate floss filters of any kind let alone in micron pore size ratings. Is it possible you don't need expensive porous ceramic cups at all? Just thinking outside the cup.


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## dtectr (May 29, 2011)

All coffee filters are cut from a long, continuous sheet of paper filter material - with its own unique, but also BASIC or SIMPLE warp & weft (weaving terms - the vertical threads are the "warp"; whereas the "weft" runs "right to "weft""). If you merely stack them, as they come from their packaging, basically the weft (left to right) placement of openings will be constant, leaving a fairly straight-ahead filtering system.

However, If you rotate each disc 45 degrees when you stack them (3 or more), you will create a much tighter arrangement of filtering medium. Try it before you dismiss it - & don't forget to crimp the bottom point of the cone, as Hoke advises, as this provides considerable structural integrity, especially when filtering hot or "strong" solutions.

FWIW


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