Spent a few hours with Bill Pentz re: cyclones

[Lance Alldrin]

In my pursuit of a replacement system for my Grizzly 1029, I ended up on Bill Pentz's website. The info looked good and he has spent huge amounts of time building and testing for the home shop market. I ended up ordering a kit from him not realizing he was just a 2 hr drive from my place.

I ended up driving down to get my unit. He was kind enough to have it all soldered up and threw in a few extra pieces he had laying around the shop to get me closer to be in a "sucking" situation!!!

We ended up talking about woodworking/health issues/dust collection in general. I walked away with a page or two of notes on individual tool hookups, ducting ideas etc.

Due to health concerns and time constraints, I don't believe he's offering kits anymore but you can get his plans online or order a kit from a supplier (link on his site) who makes clear cyclone.

I guess my point here is that I wanted to publicly thank him for his dedication to this pursuit. Too many times what we read in the woodworking magazines as far as tool reviews is "tainted" just a bit with advertising bias. Bill has real world numbers and systems that are proven to work! Thanks!!!


Lance
Chico CA

[Scott Parks]

Yes, Thanks Bill for what you've done for the hobbiest woodworking industry!!!!

I've been following Bill's work for 4 years, but have not yet built a cyclone. This year I better git-r-done.

[Jeff Sudmeier]

I have been watching Bill's work as well. I would like to go to a cyclone when /if I move shops!

[Mike Weaver]

Thanks for giving the nudge to say "Thanks Bill".

I bought a completed cyclone from him this past fall, and while I have yet to take t he time to finish it, I'd like to say Thanks as well.

Bill has done a GREAT service for all of us with his research and time spent, not to mention having put out a fine product.

If you haven't yet viewed his site, you owe it to your health to do so. This is not meant to knock any other DC vendor, but to merely suggest that you check out some research that I found QUITE informative.

-Mike

[Jason Tuinstra]

Lance, I never heard of Bill until my brother-in-law told me a week ago that he was going to build a cyclone with the help of Bill's site. I checked it out and it is certainly the place to go for info on dust collection. A real help! Due to the fact that I'm moving to your neck of the woods in a week and a half, I'm going to have a chance to rethink how I'm going to be doing the dust collection in my shop. I'm sure I'll use Bill's site to nudge me in the direction of a cyclone.

BTW, how far is Chico from Lemoore/Hanford area? Just curious. I know CA is a big state.

[Jay Albrandt]

Lance,

You hit the nail on the head! Bill is tiredless in his pursuit of "real" numbers as far as dust collection goes. I said it before on Badger Pond....the work Bill has done, and has shared with anyone who wants it, is the driving force of all the commercial companies sitting up and taking notice to change their units for the better. Every woodworker who buys a cyclone in the future will benefit directly from Bill's work. Not only that, but I feel that Bill's research has made tool manufacturers take notice and make inproved dust collection with adequate port sizes part of their standard design process. Soon, we will see table saws with 6" ports, bandsaws with two, four inch ports....etc..etc...

I built one of Bill's kit, and I can't say enough about it. He did all the leg work getting the other vendors like Sheldons and Wynn online so the whole process was a piece of cake.

Thanks Bill! And thanks Lance.

Jay

[Frank Pellow]

The material that I read on Bills site was a big part of the reason that I purchased a cyclone. I did consider building from a kit of his design but, in the end, decided to save the time (I was kind of busy building my shop last year) and purchase a ready-made unit from Oneida.

I too would like to thank Bill for all his research, design, and documentation.

[Chris Padilla]

Lance,

Here you go...I posted a lot of pics of the BP cyclone kit that I put together:
http://www.sawmillcreek.org/showthread.php?t=9933


Jason,

Chico is WAY up north from you...it is even pretty decently north of me. Yahoo! Maps this stuff...you'll see! Bill P. is basically in Sacramento.

[Jason Tuinstra]

Thanks Chris! I don't know how I missed your post about the cyclone. I had a busy fall I guess. After seeing all your work, are you glad you went this direction or would you have rather just purchased an Oneida or a Penn State? Sorry Lance, I'm not trying to high-jack this post. Feel free to add why you went this direction instead of a fully assembled model.

[Ed Moehlenpah]

Well, I may be accused of hijacking, but Jason, if Chris hadn't helped me, my cyclone would still be in pieces. The other thing is that from decision to build until operational, was over 9 months. If I had bought one from Oneida or Grizzly, it would have been meaured in weeks. That 9 months includes ordering the motor/kit/impellor, and waiting for all of that to arrive. Some parts took 3 months. If you have time, building your own might be educational, and might save money, if you don't have extra time, buy one. That would be my advice.
Ed

[Lance Alldrin]

Hey guys,
I went pre assembled from Bill just to save some time . I didn't have the $$$ to buy a unit from one the DC manufactures and must admit, doubted some of the numbers that have been published in various advertisements/magazines.

I'm also not a sheet metal guy. I welded in AK for a few summers and have been involved in woodworking for nearly 30 yrs so I'd rather stick to areas I'm comfortable with. Besides, I paid around 200.00 to Bill, 85.00 to jet for their 14" impeller and I had a harbor freight 5 hp (3 hp really) motor in the garage. I hope to be able to "suck" with the big boys after getting it put together!!!!

Lance

[Jim O'Dell]

Hi all!
I haven't yet ventured into dust collection except for a shop vac, which I know does nothing. I have decided that the next machine I get is a cyclone. I'm leaning toward the Clear Vue right now that is Bill's design. I understand that Bill and Ed are working very closely together, and will have a new impeller design out shortly, with another design in the works for sometime later on. I've been impressed with Bill's willingness to open up the data he has gathered over the years. I know he did this research for himself because of his health problems with dust, but only a true gentleman would make this information freely available to all of us. I have also been equally impressed with Ed Morgano of Clear Vue Cyclones for his quick and knowledgeable answers to my newbie questions on this subject. So add my "Thank You" to the list. Without Bill's work of the heart, I'd gone on oblivious to the problems I was inhaling. Jim.

[Allan Johanson]

To all you guys with large cyclones:

I've posted this info on some other forums and now seems like a good time to summarize some of my findings for you.

I've built a 14" impeller based Bill Pentz cyclone and am extremely happy with the performance. For duct sizing, here are some real test numbers for you that I did a while back to illustrate the effect of smaller drops on a 7" main duct. I used Dwyer magnehelic gauges and the proper pitot tube for the tests.

7" main duct alone: 1490 cfm
7" main duct with 10' of 6" flex hose: 1160 cfm
7" main duct with 10' of 5" flex hose: 1070 cfm
7" main duct with 12' of 4" flex hose: 749 cfm
7" main duct with 12' of 4" flex hose hooked up to my Excalibur overhead guard (a 3" hose at the end of that): 478 cfm

Perhaps a good way of visualizing what you are doing to your ducting when you have small diameter drops is this:

You are taking your main duct with both hands and choking it to death. The more to choke it, the less it will breathe.

Most of you are probably planning on or using a 6" main duct and will have a 6" exhaust from the blower. If your goal is to get that magical 800 cfm at the tools with a 6" drop, then you'll easily get it.

But if you'd like to get more from your cyclone, then consider the numbers above and the following:

I have a 7" main duct and an 8" exhaust on my cyclone and as a test I reduced the 8" exhaust with a reducer after a couple feet. Here are my airflow readings when I restricted the exhaust to the sizes listed below:

8" exhaust: 1486 cfm
7" exhaust: 1455 cfm
6" exhaust: 1407 cfm
5" exhaust: 1288 cfm

I also did some wye tests on my 7" main duct.
I did a test with 5+5 and 5+6 drops from a 7" main using a 7x7x7 wye with the appropriate reducers on each of the two 7" branches. Here are the results:

7" main wye tests

cfm notes
1494 7" main alone
1465 7"x5"x6" wye alone
1395 7"x5"x6" + 10' of 5" flex + 10' of 6" flex
1395 7"x5"x5" wye alone
1364 7"x5"x5" + 10' of 5" flex + 10' of 5" flex

It's interesting to see that the simple act of reducing a line seems to cause a lot of the restriction. It's also interesting to note that in the case of these wyes, if one went by math alone then even the 7x5x5 wye shouldn't cause any restriction since the combined area of two 5" openings is slightly greater than a 7" opening. And 5" + 6" openings are definitely far greater than a 7" opening. BTW, when the 7x7x7 wye alone was in place, there was no reduction in airflow. I came across another site that said there were over 200 variables involved in figuring out airflow calcs in a situation like this. It's a far more complicated beast than I thought. I don't think I'll be completely understanding it anytime soon.

If I look at the test results from necking down my 7" main duct with 10 feet of 6" hose the airflow was around 1160 cfm. From my test above two 5" drops on a 7" main will give me 1364 cfm. 200 cfm more at the tool. I don't have a 6x4x4 wye, but from what I've seen with restrictions on a run if I did this test I wouldn't see 1160 cfm with the 7" main reduced down to two 4" drops. It would probably be under 1100 cfm.

Now going from one hood @ 1160 cfm compared to two of them combined @ 1364 cfm at first doesn't sound like a lot, but I suppose there are times where having two hoods or a well designed single hood with two sources of air intake might provide a significant boost in performance. Of course this may only matter to a person with respiratory problems. But living with an asthmatic wife makes me think of these folks more. Especially when I fire up the Performax sander. Boy do I need to make a new hood for that!

Cheers,

Allan

[Mike Weaver]

To all you guys with large cyclones:

I've posted this info on some other forums and now seems like a good time to summarize some of my findings for you.

I've built a 14" impeller based Bill Pentz cyclone and am extremely happy with the performance. For duct sizing, here are some real test numbers for you that I did a while back to illustrate the effect of smaller drops on a 7" main duct. I used Dwyer magnehelic gauges and the proper pitot tube for the tests.

[snip GREAT measured data]

Cheers,

Allan

Allan,
Thanks for the great info!!
-Mike

[Scott Coffelt]

I've got one of the Dust Eliminator cyclones. Great unit, but honestly I am not sure I would go through the building of it again. Specially since Grizzly is coming out with their new line. It took many, many hours to build. That time could have been spent on making dust, not making metal shavings and solder drips.

Seriously calculate your time to build and factor that in.