# Dust Collector

• posted on January 2, 2004, 6:56 pm
For those who requested a drawing/picture of my dust collector mod, it is on "alt.binaries.pictures.woodworking." under "dust collector." It is offered, rough as it is, in the hope that it will help.
For those who suggested upgrading to a larger unit, two things: Some of us are restricted to 120v. Also, the cost is actually much greater, if you have an existing dust collector.
For those who asked if this were not just making a single filter bag system into a two bag system, as you will see, you were "spot on" as the Brits say.
Deb
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• posted on January 2, 2004, 5:31 pm
Dr. Deb wrote:

Thanks a bunch. Won't be able to see it till after work since I can't get any binaries here, but I'm glad I'll be able to take a look before we leave for vacation.

Cool. Just one more little detail, if you don't mind; how are you estimating or measuring your CFM?
Dan
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• posted on January 3, 2004, 6:23 am
I read an ad in one of the mags I subscribe to that said for 1 micron filter you should figure 40-45CFM per sq ft. Since the bag was 30" high and had a diameter of 20" simple math 20x3.1416x3084.96sq in, divide by 144 13.09 then times 45 = 589.05 CFM.
It seems about right when compared with the Jet 650CFM DC I had before this one.
Deb
Dan wrote:

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• posted on January 3, 2004, 4:16 pm

You forgot the area of the end. You've got another pi*r^2 or 3.14 * 10^2, which is about another 314 sq in. By my calculations with your formula, that gives you about 685 CFM.
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• posted on January 4, 2004, 2:17 am
For good dust retention and low static pressure through the filter, filter air velocity should be reduced to more on the order of 5 CFM per square foot, not 40-50. The less pressure loss through the filters, the more air you can move.
There is a severe lack of understanding of the principles of GOOD dust collection, or more correctly, dust ELIMINATION in the wood shop atmosphere. I recommend investing some time at Bill Pentz's web site at http://cnets.net/~eclectic/woodworking/cyclone/index.cfm . I also produce cyclone kits and blower housings based on Bill's cyclone design. See http://cnets.net/~eclectic/woodworking/cyclone/ClarkesKits.cfm for more info.
CE
"Dr. Deb" wrote:

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