Need some dust collection advice

[Paul Schaefer]

When I decided to add dust collection to my shop 7 years ago, I did a lot of research on Bill Pentz’s site and other places. I didn’t have the money or space for a cyclone. I came to the conclusion that all of the single-stage dust collectors failed to meet Bill's suggested requirements for dust collection, so I bought the least expensive failure, the Harbor Freight’ 2HP’ unit. I’m re-visiting that decision, and I’d like some help from the Creek.

My shop setup is as follows: tools running off the DC are a 14” bandsaw, 5” jointer, 11” lunchbox planer, 9” radial arm saw, and a router table. All have a 4” DC port as close to the point of dust creation as possible. I connect each one individually to the DC using a 4’ length of black flex line. All of the ducting on the machines that go from the point of collection to the flexline hookup are PVC sewer and drain line, and all 90* bends are made with two joined 45* elbows. The DC has a Thien baffle in the collection ring and a Wynn 35A pleated filter. An old swamp cooler exhausts shop air through the garage door.

I may be moving in the next few years, so setting up a duct and gate system is not something I want to invest in. Furthermore, I can swing the flex line from machine to machine without moving the DC more than a foot, so I really don’t feel the need for a duct and gate installation.

I would like to add a second point of collection to each machine – for example, putting dust collection above as well as below the bandsaw table. With my current DC, I could probably add a 2” or 3” above-tale hose and still maintain proper airflow. However, with a Grizzly G1029, it looks like I could support two 4” collection ports on each machine. It spins a 12.75” impeller with a beefy motor (9A@220V), and its specs are what Pentz recommends as minimum for fine dust collection.

If I bought a new DC, I would transfer over the Wynn filter and install a new Thien baffle, but probably not build a separator.

Is the upgrade to the Grizzly (or another unit with the same specs) close enough to ‘real’ fine dust collection in my particular application to be worth the money? My research indicates yes, but I’d like some other opinions.

Thanks!

[Randy Heinemann]

I'll just generally answer your question. I feel that using the best filtering available is important. For me, with regard to my cyclone, a HEPA filter. For smaller tools like sanders and routers, I also use a vac with a HEPA filter. So, for me, the answer is always yes when it comes to getting the best filtering possible. As a side note, I also run a ceiling mounted air cleaner and use a personal mask. I'm sure that not everyone will agree.

[Jim Dwight]

The benefit of a cyclone is it prevents you from having to clean the filter as often. In my experience, it is a big difference. A thein separator does not catch nearly as much fine dust. I've used both. If the specs on your Wynn filter are good, I see no reason to change it. But keeping it clean will make a big difference I the amount of suction you will have at tools. A super dust deputy would help that a lot. I would get that before I got a new DC. Another idea for filtration is to not filter but just exhaust outside. That only works for shops without heat or AC - like mine. But it will give you the most airflow and least work. A cyclone would help you not make a mess. I would look for U-tubes about people fixing up HF DCs. Some people even went to a larger impeller. There seems to be a lot you could do without changing DCs. Things like filters and cyclones can also be transferred to a new DC if you ultimately end up there.

[Paul Schaefer]

Randy - I also always wear a 3M respirator whenever I'm making dust. And the Wynn filter has a MERV 15 or 16, I think - no worries about the filtration. It's airflow I'm concerned about.

Jim - Yep, seen a lot of HF mod information. The stovepipe mod is one I've been thinking of doing, actually. And I've read about guys were putting in new Rikon impellers in for $119 shipped. But once you add the cost of a new impeller, plus the original cost of the machine, you're talking about ~$270 into the project. A new Grizzly is $444 shipped with a cyclone separator thrown in, and that's assuming Grizzly doesn't do a Christmas sale.

You're right, the baffle in the separator ring only catches the chips (though it's GREAT for that!). But I'm a bit leery of putting any kind of separator on the HF. Its specs are marginal as-is, and a separator would cut that even further. I don't know if running without a filter and venting outside would allow me to make up the CFM loss from a separator, though if it did, you're right - I could vent externally without spewing dust all over the neighborhood. You seen any numbers on loss from adding a separator vs gain from direct venting externally?

[John TenEyck]

I did what Jim said - got rid of the filters and send the exhaust out a window - and now I have enough flow from my 2 HP DC to do a really good job with all my machines. I also ripped apart the DC and mounted the fan housing directly on top of my re-purposed cyclone to reduce the pressure drop it caused. I gained about 4" of pressure drop getting rid of my 1 micron bag filters and another 3" or so by putting the fan on top of the cyclone.

Blowing the exhaust out a window gives the highest airflow and is the best air filtration possible. I've had no trouble maintaining temp. in my basement shop in the Winter (I live in WNY and it gets cold here.) nor with RH control in the Summer, the dehumidifier takes care of that. Of course, I have to open another window to provide makeup air, but I have that rigged to make it simple from the DC on/off switch.

I spent nothing and have a system with much higher performance both in CFM and air quality, performance remains constant over time because there are no filters, and there is no required filter or bag cleaning/maintenace. Hard to beat.

John

[Paul Schaefer]

John, you're a gold mine of information! What kind of cyclone do you have? And what kind of DC - the HF only has about a 10" impeller. My results might not match yours if you're starting out with a better system. Do you have ducting run throughout the shop, or are you connecting to one machine at a time?

BTW, you gave me some advice about a DeWalt MBF almost two years ago that convinced me to buy it. It's (finally!) almost up and running, just need to do final tuning and adjustments. Can't wait to put it in service.

[Nike Nihiser]

There is a lot of info at the workshop forum

[John TenEyck]

Paul, here's what I posted at another site I frequent, back when I did this last Winter. To answer you question about the cyclone, it's part of a DustKop industrial vacuum cleaner that I repurposed. The design isn't ideal, but it works well enough to remove all the chips all but the finest dust.

You will love the Dewalt ! My GWI is a key player in my shop.

John
---------------------------------------------------------------------

I've had a Grizzly 2 HP dust collector for at least 15 years. It's similar to this one:




I piped it to 6" ductwork running across my shop under the ceiling, and dropped 5" hose to each machine. Soon after I got it I came by a small cyclone from an industrial vacuum cleaner and I installed it in front of the dust collector to collect the big stuff. About 10 years ago I "upgraded" the stock 30 micron bags to 2 micron ones, top and bottom. I noticed that the flow was reduced, but it still pulled everything from my various pieces of equipment so I was fine with it. Then I bought the big bandsaw last Summer. I ran 6" duct from the main 6" trunk to the bandsaw, installed a 6 to 4 x 4 wye connection and ran two short lengths of 4" hose to the bandsaw. At that point, the poor performance of the DC showed itself in spades. Sawdust would quickly build up in the bottom of the saw and some would get carried up to the top wheel as well. Worse, sawdust would get trapped between the blade and lower wheel.

I needed to do something and I considered several options, including just buying a new, larger DC with a canister filter. But before I spent money I wanted to see if I could improve the performance of what I had. I started by making a simple water manometer from a length of clear plastic tubing, and set about measuring the pressure drop at various locations. I've forgotten all the numbers but I do remember that I only had a couple of inches of pressure drop at the bandsaw, and that wasn't going to do it. I disconnected the DC from the cyclone and bags and ran a hose out a window. I had 11" of water, exactly what Grizzly claims. Note, however, that was with no bags. When I added the bags back I only had 7"; not good. I added the cyclone back and I was down to only 3 or 4".

With some council by TDPKE (many thanks for the help) I took the DC apart and coupled it directly to the top of the cyclone. I sized the opening to match the outlet of the cyclone, which was around 8" diameter. I increased the outlet hose size from 5" to 6" and ran a hose to a nearby window. What I have now looks like this.





I built a manifold for the hose at the window, with an access port, so I can open/close the window as desired.





On the outside I removed the fine window screen and replaced it with 1/4" hardware cloth. The dust you see on the window and ground is after running the drum sander for a couple of hours; not bad and OK with me.





Of course if I'm now blowing air out of my shop I need makeup air, so I knocked out a couple of glass blocks in the window across my shop and built a barometric damper. It works great, and the boiler and hot water heater are unaffected by the DC.





Now that the weather has warmed up, I'll knock out one more block and install a window like at the outlet end, and then build a larger barometric damper on the inside.

The cyclone is short and stubby, but is actually pretty efficient at capturing even fine sanding dust:





So how does it all work? Well, I now have about 4" of pressure drop at the bandsaw and I can resaw and cut veneer for hours w/o dust building up inside:





Performance at all my other machines is greatly improved as well. You have to tug at the blast gates now to open them. The motor amps. are well within the max. listed on the motor plate so there's no danger of overloading it.

I've saved myself about $2K and that makes me happy. The penalty is that I'm sucking cold air into my shop in the Winter and hot/humid air in in the Summer. But I have heat and a dehumidifier in my shop so it should remain comfortable. Time will tell but so far so good.

John

[Matthew Hills]

John,
how is the noise outside your exhaust window? Any potential issues with neighbors?
(that seems to be a recurring theme when people consider venting their clearvues outside)

Matt

[John TenEyck]

Just found where this went.

The noise is low outside. Yes, you can hear it but I don't have any neighbors behind my house. I doubt it would be an issue unless your neighbors were Gray Poupon" close and liked to complain about everything.

John

[Robert Engel]

Paul,

I did the same thing as John. Exhausting outside makes up the CFM loss of a cyclone. A 1 1/2HP Jet blower does an adequate job using 6" ducting.

Since you have the capacity I would go with a cyclone. Huge benefit simply from the standpoint of time savings emptying shavings. I use the Super Dust Deputy plastic version and it works great.

I don't know of a practical way to collect a bandsaw other than under the table. Rob Cosman has an interesting video on modification to collect a BS.

Other than that your system sounds fine.

[Jim Andrew]

I have a 3hp cyclone and vent outside most of the time. I did put a T on the exhaust and made an 8" gate so I can close the gate and run my exhaust through the filter, like in winter when it is very cold, but most of the time exhaust outside. Built my own dryer vent type dump, and see very little dust on the ground. The increase in performance while dumping outside is amazing.

[Paul Schaefer]

On collection from the bandsaw, I currently have a jerry-rigged setup that puts a 2.5" collector at the top of the table, in addition to the 4" I have underneath. It's bad enough not to describe further, but it does make a difference. I think I could have a flex line either attached to to upper guide rod or on its own moveable support that would do at least as well.

[Paul Schaefer]

Everyone, thanks for your answers. This is certainly taking me in a different direction than I expected! I thought I'd get a mix of 'Get a real cyclone, anything else is just wasting your time', and "Get the Grizzly or Delta and call it a day,' and have to divine a course of action from the ensuing debate. I did not expect a chorus of, 'your system should be fine, just slap on a cyclone and vent it outside'. Which is why I came here - to take advantage of everyone else's experience, even if it takes me in a direction I don't expect!

I don't think I'll have a problem with noise complaints, even in a residential area. I try to keep the garage door open when working, which means the DC, saws, and the big fan all running at once. Haven't had a complaint yet.

I'm a little more concerned about venting dust into a residential area. However, John's picture looks like it's pretty minimal, even with a very dusty operation. Certainly less of a mess than what I make when I fire up the belt sander in the back yard, so I *think* it'll be okay. John, Jim, Rob - do you live in residential areas, and has the dust or noise exhaust ever been cause for concern? (John, I see that your answer is aready likely 'no')

Biggest concern I have is the adequacy of the HF fan and motor. I finally came across a comparison of 1.5-2hp units done by Wood magazine in 2008, and my HF unit was by far the bottom of the class - well below John's Grizzly and Robert's Jet. Smaller impeller, less real amp draw from the motor. Even venting outside, do you really think I'll do well enough with the runt of the litter in its class?

[Mike Heidrick]

John, how are you measuring static pressure loss gains?