# whatman filters?



## rewalston (Jun 9, 2014)

I've seen posts about what some of the people here in the forum use for whatman filters, such as #1 or #2, but the ones I've found talk about a micron size, so I'm not too certain how to equate this to what has been mentioned. Any suggestions? I'm looking at getting a buchner funnel and filters from Cole Palmer.

Rusty


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## Westerngs (Jun 10, 2014)

For vacuum filtration you want glass microfiber. Find some in the 1-3 micron range. If you can find "generic" you are better off as Whatman filters are expensive. Look also at Fisher Scientific and VWR Scientific and order the least expensive.


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## goldsilverpro (Jun 10, 2014)

rewalston said:


> I've seen posts about what some of the people here in the forum use for whatman filters, such as #1 or #2, but the ones I've found talk about a micron size, so I'm not too certain how to equate this to what has been mentioned. Any suggestions? I'm looking at getting a buchner funnel and filters from Cole Palmer.
> Rusty


Whatman papers are expensive. It does seem like they're now selling them by micron size instead of #1, #5, etc. Here's a guide that may help.
http://193.218.17.133/ex/downloads/filtration/Whatman_filter_paper_guide_de.pdf

The glass fiber papers are even more expensive. I usually used the regular papers for vacuum unless I had something that was very fine, in which case I used the glass fiber ones. If it were me, I would first try some of the cheaper Chinese papers on eBay. They're about 1/3 the price. For vacuum filtering, to prevent leakage you need a size that will fit flat on the bottom of the funnel, although you can cut larger ones to fit.


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## rewalston (Jun 10, 2014)

Thanks GSP, I'm looking at a 425mm funnel and 4.25 cm papers about $12 /100 filters


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## 4metals (Jun 10, 2014)

For years I used a rather inexpensive paper called sharkskin, I believe it was made by Whatman. It held up well and didn't blow through often. 

Another trick to speed up filtration is to use a circle of fiberglass window screen smaller than the paper by at least 1/2" all around. Place it on the buchner funnel and put the paper on top. The paper will still seal at the edges because there is no screen at the edge. The mesh keeps the paper from hitting the ceramic and allows much more of the paper to effectively filter. The screens last a long time.


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## goldsilverpro (Jun 10, 2014)

Listen to 4metals (always!). This window screen thing really works well.


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## Lou (Jun 11, 2014)

True that^


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## rewalston (Jun 11, 2014)

That's a good idea thanks 4Metals. Now to find all the parts I need. I've got an assortment chosen from Cole Palmer and ProLabScientific. The only thing I'm having fun (sarcastic) finding is the stoppers. Need only a few but everywhere I've looked they sell by the pound..I have no need for 16 stoppers I only have one filter flask.


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## 4metals (Jun 11, 2014)

Action mining services,

rubber collars fit beneath the Buchner funnel and seal it to the vacuum flask 

http://actionmining.com/cgi-bin/online/storepro.php?product=10000:ADAPTER4000

You can buy only one from them. The size is based on the size of the flask you are sealing to not the funnel size.


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## rewalston (Jun 12, 2014)

4metals said:


> Action mining services,
> 
> rubber collars fit beneath the Buchner funnel and seal it to the vacuum flask
> 
> ...


Thanks 4metals will check them out.


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## goldsilverpro (Jun 12, 2014)

I usually bought a set of those rubber stoppers that 4metals mentioned. With a full set, you can adapt to most any size funnel.
http://www.sks-science.com/funnels-p-6442.html


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## kadriver (Jul 14, 2014)

rewalston said:


> I've seen posts about what some of the people here in the forum use for whatman filters, such as #1 or #2, but the ones I've found talk about a micron size, so I'm not too certain how to equate this to what has been mentioned. Any suggestions? I'm looking at getting a buchner funnel and filters from Cole Palmer.
> 
> Rusty



Not all Büchner funnels are alike.

Make sure that you check the size of the tiny holes in the floor of the Büchner funnel.

You want them to be very fine/small as opposed to too large.

I bought a Buchner that had large holes and experienced frequent filter paper failures.

The Büchner funnels with the smaller holes reduces the frequency of filter paper failures because with smaller holes there is less filter paper exposed to the vacuum.

Large holes in the floor of the Büchner funnel expose a greater surface area to the vacuum and thus increases the risk of failure.

When I wash cement silver in my 12.5cm/125mm plastic two piece Büchner funnel I always use two filter papers stacked on top of each other in the funnel to help prevent a "blow through" from the glass stirring rod contacting and tearing the filter paper.

kadriver


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## Harold_V (Jul 17, 2014)

4metals said:


> For years I used a rather inexpensive paper called sharkskin, I believe it was made by Whatman.


Nope! Sharkskin was made by Schleicher & Schuell (S&S). I have, at my right elbow, the remains of a pack, 32 cm in size, as I type. 
A wonderful filter paper, to be sure, but it isn't worth a damn for holding back fine particles. I used it mainly for filtering the values from the mud, after chemically processing polishing wastes. I filtered by gravity, not a Buchner. 

Harold


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## goldsilverpro (Jul 17, 2014)

I think Whatman bought out S&S quite a few years ago. In any case, Sharkskin is now sold under the Whatman label.
http://www.fishersci.com/ecomm/servlet/fsproductdetail_10652_5906967__-1_0


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## Harold_V (Jul 17, 2014)

goldsilverpro said:


> I think Whatman bought out S&S quite a few years ago. In any case, Sharkskin is now sold under the Whatman label.
> http://www.fishersci.com/ecomm/servlet/fsproductdetail_10652_5906967__-1_0


Thanks, Chris. Considering I've purchased nothing since 1994, I was not aware of the change of ownership. In any case, Sharkskin is one of the best papers I ever used, although just for coarse filtration. 

That being said, unless there's been a huge change in the wrong direction, Whatman papers beat others, hands down. I used them exclusively for filtering gold chloride, #2 for the first refining, and always #5 for the second refining. I tried others. Sergeant Welch, for example, sold what was marketed as a #2 equivalent, but it didn't appear to me to filter as well as the Whatman #2. I still have what remains of a pack of them, which I use for filtering zinc chloride, used for spraying my roofs to prevent moss. 

Harold

Edit:
Out of curiosity, I visited the link you provided. I took note of the price today. Took my breath. I used to pay about $10 for a pack of 100 filters, 32 cm in diameter. Whatman #5 was about $50/100. I shudder to think what they may be asking today.


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## Irons (Jul 17, 2014)

I picked-up a couple of 100 packs of Whatman Sharkskin 8X10 inch sheets for $9/pack on fleabay a while back. I just trim them to fit after folding them.
There's a whole section on filtering supplies. If you don't mind waiting for something you need to come up for auction. Sharkskin Paper is not designed to be scraped clean because of the rough surface, thus the name.


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## 4metals (Jul 17, 2014)

Harold,

How effective is the zinc chloride spray for roof moss? Is it as effective as a zinc strip or a copper strip? How often do you need to re-apply it?


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## Harold_V (Jul 18, 2014)

4metals said:


> Harold,
> 
> How effective is the zinc chloride spray for roof moss? Is it as effective as a zinc strip or a copper strip? How often do you need to re-apply it?



Very effective. Before I applied any to the roof, I sprayed some on the ground, Killed it quickly, and it stayed dead for the year. 

We get, on the average, about 60" of rain here. I spray once each year, and it keeps it mostly at bay. Been dissolving scrap zinc to make my spray, but not what I'd call on a scientific basis. Once dissolved, I use the concentrate mixed with about three times its volume with tap water. Seems to work OK, but you can always increase the concentration if needed. Now I need a good supply for zinc, as I've nearly exhausted all the scrap I had on hand. 

As I've aged, my equilibrium isn't what it used to be, so I may need to explore something that doesn't require me to get on the roof. I've seen the strips of zinc, or I guess I could fasten a length of copper wire at the top of each side. Don't have a clue if that would work, or not. 

What do you do to keep moss in check? Here, if allowed to remain, it can destroy a roof in short order. 

Harold


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## kurtak (Jul 18, 2014)

Harold_V said:


> Now I need a good supply for zinc, as I've nearly exhausted all the scrap I had on hand.



die cast from the scrap yard

Kurt


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## Irons (Jul 18, 2014)

http://www.rotometals.com/Zinc-Roofing-Soft-Flashing-s/68.htm

These folks have good prices and inventory.

Here's another solution you might want to try:

http://lawncare.about.com/od/turfgrasspests/qt/getridofmoss.htm


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## FrugalRefiner (Jul 18, 2014)

Harold_V said:


> Now I need a good supply for zinc, as I've nearly exhausted all the scrap I had on hand.


I've been getting used wheel weights from the mechanic that works on my truck. There is a mix of steel, lead, lead alloy, and zinc weights. You have to melt them down to get the steel clips off the zinc weights.

Dave


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## philddreamer (Jul 18, 2014)

My son sprinkled laundry detergent on his roof, sprayed some water, and a couple of days later the moss was black. Then he spray washed the moss off. Every so often, he sprinkles more detergent to keep the moss under control. 8) 

I think he said, its the phosphorus that kills the moss...

Phil


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## goldsilverpro (Jul 18, 2014)

When Whatman bought S&S, they stopped making S&S 596 papers, which I used for most everthing for about 20 years. They were cheap, thick, strong, medium speed, good retention, and had good acid resistance. Of all the papers I used, they were the best. I heard that there is a Whatman equivalent but I had problems getting a straight answer from Whatman.


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## Lou (Jul 18, 2014)

Yes, it's a shame. Every now and then some of these legacy papers end up on ebay. 

I've been on a big polypropylene felt kick lately.


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