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Dust Separation/Collection Efficiency Question

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Forum topic by matt5895 posted 02-24-2020 10:02 AM 467 views 0 times favorited 10 replies Add to Favorites Watch
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matt5895

5 posts in 334 days


02-24-2020 10:02 AM

Topic tags/keywords: dust collector dust separator efficiency

I’m about a month away from having a two week vacation (stay-cation!) and have dust collection system as my main project. I have designed the system over and over during the past few months (on paper and in my head). I’m going to buy a new dust collector as step one but which I buy will be largely guided by the design/strategy I settle on.

My basement is mine. The only part of my house where my prerogative rules. My wife has washer and dryer down there but she has been asking to relocate them and I am happy to oblige. The space is rectangular and open other than the stairwell down which is directly in the middle and support beams like you’d expect. The ceiling is relatively low (about 6’8’’ max). 30’ by 60’ in total. The area work in presently is one half (30’ by 30’). Once the laundry operation is moved I could use a 20’ by 60’ space. Some portion will have my kids stuff for storage so will never have full use of it all. I guess the only other variable that would be important is that I’m the only worker there and it’s always only one tool at a time in operation. (Bandsaw, planer, Sanders, lathe, table saw . . . all big dust generators but only one at a time).

I have bought and read that “Workshop Dust Control Book”, but I read it less like a novel and more like reference. The couple questions I have are (1) is a rectangular shaped work space with one main line (no branches) and drop downs generally the most efficient dust collection set up and (2) does a dust separator close to the collector work better than a separator close to each machine? ** regarding second question I’m eyeing a 3hp grizzly single stage collector rather than two stage and so definitely want to incorporate a separator and I know the separator will result in resistance but not sure if a separator close to the collector where there’s more static pressure will work better than individual separators at each machine.

Thanks in advance. Btw everything that I think “I know” about dust collection I’ve picked up from books and online forums so don’t be bashful about pointing out that I’ve sized something up completely wrong . . . unless you’re going to suggest introducing my prerogative to my wife’s areas of the house because we share this iPad and there’s some risk she stumbles on to this post.


10 replies so far

View Fred Hargis's profile

Fred Hargis

6043 posts in 3169 days


#1 posted 02-24-2020 11:32 AM

I can’t answer your question with data, but I have to think you want your separator next to the DC. Not only will that be simpler, it will be cheaper….and you will wind up spending some money on ductwork. For the ductwork, you generally want as few turns/elbows as possible, and you want what turns/elbows you have to be gentle, not abrupt 90s. Personally I would run one main trunk the length of the work area, and split off drops for the tools. If you haven’t though about the size of the ducts, you should. Generally speaking, larger ducts allow more air flow. But they can be too large. The velocity can slow in an oversized duct to the point you get clogs. But a 3 HP DC should support 6” ducting without any trouble. As for the elbows, the common recommendation (with PVC, if that’s your choice) is to use 2-45˚ els, with a short piece of straight pipe between them. I also suggest that you run the 6” all the way to the tools, including modifying the ports for 6” wherever possible. Thsi is only one of many opinions you’ll get, so i wish you the best with your choices.

-- Our village hasn't lost it's idiot, he was elected to congress.

View clagwell's profile

clagwell

142 posts in 468 days


#2 posted 02-24-2020 05:47 PM


... does a dust separator close to the collector work better than a separator close to each machine? ** regarding second question I’m eyeing a 3hp grizzly single stage collector rather than two stage and so definitely want to incorporate a separator and I know the separator will result in resistance but not sure if a separator close to the collector where there’s more static pressure will work better than individual separators at each machine…

Location makes no real difference. It has the same effect anywhere in the ducting path.

Some questions for you:

Which Grizzley 3HP, with filters or bags?

What kind of separator are you considering, Thein or cyclone or other?

What are you trying to accomplish with the separator? Less frequent bag emptying, filter cleaning, or other?

-- Dave, Tippecanoe County, IN

View tvrgeek's profile

tvrgeek

593 posts in 2325 days


#3 posted 02-24-2020 05:59 PM

Salesman in a store talked me out of buying the Oneida separator to add in front of my Jet collector with can filter. He said a the filter will outlast me.

Bags let all the fine dust that is what kills you right through. They should be called chip collectors.

View ibewjon's profile

ibewjon

1372 posts in 3469 days


#4 posted 02-24-2020 06:04 PM

With the low ceiling, I would run along the walls. Center the DC on short wall or in a corner with a branch each way, and gates at first y to limit suction to one branch. Just a y at each tool, and a long radius 90 at each corner. Less ups and downs and fittings. It works great for my system. I use 5” steel with a 2 hp. 6” may be good for a 3 hp. 26 guage steel snap lok duct is cheaper and lighter than PVC, and the proper fittings are available. Seal the lengthwise joints and the joints in the adjustable 90’s. Use aluminum tape on joints, not screws. Screws catch planer and jointer shavings.

View pintodeluxe's profile

pintodeluxe

6082 posts in 3489 days


#5 posted 02-24-2020 07:34 PM

It seems most people need to work through the trials and tribulations of setting up a dust collection system. IE: start with a single stage, and realize the bag or filter clogs almost immediately. So you go shopping for a separator. Only to realize that fine dust still passes to the filter. Then people usually try to build their own cyclone with a motor / cone size / impeller diameter that was never tested together. Only to realize that it under-performs for the amount of money and time you spent building it.

I implore you! Please please please look for a commercially available cyclone. If new is not in the cards, get a used one.

I have a 2hp Tempest cyclone with a 14 or 15” impeller and both collection and separation are fantastic.
I paid around $200 for the setup used, plus some special order 26 gauge metal pipe from Home Depot.

-- Willie, Washington "If You Choose Not To Decide, You Still Have Made a Choice" - Rush

View jeffswood's profile

jeffswood

27 posts in 3150 days


#6 posted 02-24-2020 08:14 PM



It seems most people need to work through the trials and tribulations of setting up a dust collection system. IE: start with a single stage, and realize the bag or filter clogs almost immediately. So you go shopping for a separator. Only to realize that fine dust still passes to the filter. Then people usually try to build their own cyclone with a motor / cone size / impeller diameter that was never tested together. Only to realize that it under-performs for the amount of money and time you spent building it.

I implore you! Please please please look for a commercially available cyclone. If new is not in the cards, get a used one.

I have a 2hp Tempest cyclone with a 14 or 15” impeller and both collection and separation are fantastic.
I paid around $200 for the setup used, plus some special order 26 gauge metal pipe from Home Depot.

- pintodeluxe

This is such great wisdom. If I had the budget for 3hp DC and was starting from scratch there is no chance that I would not buy a cyclone right away. Even more so for a basement shop as the dust will end up in the house.

View HorizontalMike's profile

HorizontalMike

7852 posts in 3590 days


#7 posted 02-24-2020 08:25 PM



It seems most people need to work through the trials and tribulations of setting up a dust collection system. IE: start with a single stage, and realize the bag or filter clogs almost immediately. So you go shopping for a separator. Only to realize that fine dust still passes to the filter. Then people usually try to build their own cyclone with a motor / cone size / impeller diameter that was never tested together. Only to realize that it under-performs for the amount of money and time you spent building it.
I implore you! Please please please look for a commercially available cyclone. If new is not in the cards, get a used one.
I have a 2hp Tempest cyclone with a 14 or 15” impeller and both collection and separation are fantastic.
I paid around $200 for the setup used, plus some special order 26 gauge metal pipe from Home Depot.
- pintodeluxe

+10 on what pintodeluxe suggests!

HOWEVER, regardless of whatever DC system you choose/install,... it will NOT be enough particularly in a house basement. I say this because even the best DC system fails to collect much of the very fine stuff (that never settles), hence the need for a separate “air filtration” system. This is not hard to do and it makes for a great DIY project.

I now have 2 air filtration units complementing my HF-DC w/Wynn-NANO-filter plus cyclone. All I can say is that YOUR nose will tell the difference within 1-2min when running. Actually, since then when running only my DC/Wynn/Thein-Separator, I can actually smell/feel the missed dust in my nasal passages. FWIW, I have a 24’x30×10’ shop (about half your intended space) and use TWO squirrel cage air filtration units on opposite walls and get a great CCW circulation. Well worth the effort, IMO. Much needed protection for the rest of the family in a combined house/basement-shop combination:
https://www.lumberjocks.com/topics/241361

-- HorizontalMike -- "Woodpeckers understand..."

View fivecodys's profile

fivecodys

1603 posts in 2312 days


#8 posted 02-24-2020 11:00 PM

All very good comments and I would like to weigh in as well on filtering the shop air.
I have a DC with cyclone and while it does a very good job, it does not capture all of the fines that are thrown up into the air as I work.
I did add a WEN air filter https://www.lumberjocks.com/reviews/11952 and i was amazed at what it catches.
I was working with mahogany and I was amazed how quickly the filter turned red. As I stated in my review, this was all particles that I surely would have been breathing. This may not be the best unit or the most powerful, but it is doing something as the filter shows.
I guess my point is ‘Dont forget this aspect of dust collection’.

-- A bad day woodworking is still better than a good day working.

View tvrgeek's profile

tvrgeek

593 posts in 2325 days


#9 posted 02-25-2020 11:53 AM

Curious. The slick-sheets suggest the cyclone separates more of the fine stuff so as not to load up the canister filter, prolonging it’s life more than the flappers can clean it.

I use MERV13 filters bought in bulk over my HVAC and an old furnace fan. They have not been in place long enough to either make pretty or give any thought on how often they load up, but I figure they are cheaper than my lungs.

View matt5895's profile

matt5895

5 posts in 334 days


#10 posted 03-01-2020 09:33 AM

Tvrgeek- those look really cool. The unit depicted in the upper photo is being pulled through the HVAC unit below it? Like it’s just a box (essentially) loaded with filters sitting on the intake of another unit?

Subsequent to original post I made my way over to billpentz.com and learned (1) no commercially available dust collector (cyclone or otherwise) actually works; (2) we are all doomed; and (3) he has designed some units that actually do work and I can pick one up for about $3500.

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