Need some advice on dust collection

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Forum topic by TonyJKent posted 05-25-2016 06:32 AM 1431 views 1 time favorited 16 replies Add to Favorites Watch
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5 posts in 892 days

05-25-2016 06:32 AM

I have a 300 square foot shop and I do woodworking for a hobby on the weekends and after work (about 15 hours a week at the moment). I’m currently using 2.5” shop vac + dust deputy on a cart that I wheel around my shop. Once a week I blow out all the dust from my shop. I have a Jet AFS-1000B air filter hanging from the ceiling which helps. My biggest concerns are the fine dust I can’t see that I’m breathing and the fine dust I can see everywhere.

I want to upgrade my system and here’s my short list of options:
1. Basic Harbor Freight , Jet or Griz Dust collect + top hat Thien Baffle + Wynn canister (could be 1.5 hp 110V or 2hp 220V)
2. Grizzly G0703P 1.5 hp Cyclone (includes canister filter + remote control). On sale for $675 (seems roughly equivalent to the Jet 1.5hp that costs about $1050)
3. Grizzly or Jet 220V 2hp Cyclone ($1500-$2000)

#1 is doable – But I have little spare time outside my regular job that I would rather spend it on woodworking, not building a Dust Collector.

I’m leaning towards #2 because I live 90 minutes from a Grizzly showroom, all the features are included and the price seems to double for the 220V 2hp units ($1500-$2000). For the moment I’m happy to move a hose from machine to machine like I do today. Eventually I might want to run ducting around my walls to my machines. The main trunk would be less than 20 feet long and have no more than 2 right angle turns (hopefully just one right angle in one corner of my shop) . Only one machine at a time will be used. I would rather not have to pay $1500+ for a 2HP cyclone if I don’t really need it. I would rather spend the difference on other tools like a drum sander or downdraft table. I’m not looking to build a perfect DC system but one that does the job adequately and doesn’t leave me wishing I had got something bigger a year from now. I know eventually I need to do a better job of capturing dust at the source than the standard ports on the tools have but right now. However, at the moment, I’m not really to deal with elaborate hoods or overhead collection above my table saw. Most of my current tools are hobby grade that I bought used and have 2.5” ports. (eg. Delta contractor saw, ridgid band saw, kreg router table). The one exception is my minimax jointer/planer with 5” (120mm) ports. A couple of upgrades I would like to make in the next 5 years are a sawstop table saw and a drum sander.

Exhausting the DC outside is also an option (instead of a filter) if I build a sound baffle – my neighbor’s house is 20 feet away from my shop and I assume an unmuffled exhaust would be to noisy.

I know it won’t be perfect, but will a 1.5hp do the job for the next 5 years? Advice and 2nd opinions are welcome. I’m still reading Bill Pentz site.


16 replies so far

View crank49's profile


4032 posts in 3120 days

#1 posted 05-25-2016 08:33 AM

I’m really baffled by the reasoning behind everyone’s desire to buy a decent collector and immediately start choking it down with a Thein separator which then requires you to exchange the bag for a canister to reduce the backpressure. A better solution would be to have a bigger bag, or a drop out chamber in front of a cartridge filter.

A Thein separator is a kind of poor man’s cyclone. It functions similar to a cyclone but does not require as much height and avoids the need for a tapered cone. The tapered cone, I suppose, is the part that is hard to fabricate if you don’t have a set of slip rolls and don’t know how to cut the pattern. Does anyone ever ask, “Why do I want a cyclone, or a cyclone substitute, in the first place?” Especially when I already have a dust collector? Is this perhaps a residual effect of all the money Dyson has pumped into marketing it’s bagless vacuums?

Dust collecting can be done by several types of equipment. All have a fan to suck air from a dust producing source.
The systems then use differing methods to remove the dust from the air stream. I can think of 6 methods to do this. Arranged in order of least expensive to most expensive they are:
1. Push (or pull) the dirty air through a baffled expansion chamber (called a drop out box or chamber)
2. Push (or pull) the dirty air through a filter bag.
3. Push (or pull) the dirty air through a cartridge filter.
4. Push (or pull) the dirty air through a cyclone (or Thein separator)
5. Push (or pull) the dirty air through a wet scrubber (kinda like a cyclone with water sprayed into the vortex to wash out the dirt).
6. Push (or pull) the dirty air through an electrically charged grid known as an electrostatic precipitator.

A drop out chamber will only capture heavy particles, like wood chips or grinding dust. But it’s very cheap and easy to add to the front of other systems.
A bag filter can get most of the dust as long as it has large enough surface area.
A cartridge filter is good for fine dust because of it’s pleated form which provides a large surface.
A cyclone uses pressure drop to capture dust. Very high pressure drop equals good capture of fine dust. It should be noted that a cyclone does not loose efficiency from the buildup of dust inside like a bag or filter does, but it requires more pressure in the first place. Cyclones are more expensive to operate due to the horsepower required versus an equivalent bag or filter.
A wet scrubber is normally only used for combustable dust or to chemically alter the air stream, like to reduce acid from coal fired power plants.
Electrostatic precipitators are very expensive but are used to remove extremely fine particles like smoke or pollen or bacteria and germs.

View MrRon's profile


5090 posts in 3393 days

#2 posted 05-25-2016 04:36 PM

The cyclone is the best system. Filters (bags are really filters) become less effective as soon as you turn the DC on. The really best system is to exhaust the dust to the outdoors after collecting the large chips in a pre-separator and before the fan. This eliminates all filters and bags, but may not be possible in close urban settings. My DC is exhausted to the outdoors and I can barely hear it; that sort of depends on the length of the discharge pipe; mine is 12’ long before terminating in a 90° down turn elbow. If the discharge pipe were shorter, there would probably be a bit more noise. You could extend the pipe down close to the ground to reduce the noise, if any.

View AZWoody's profile


1404 posts in 1373 days

#3 posted 05-25-2016 04:43 PM

If you’re thinking upwards of $2000 for the system, you should skip the Grizzly and Jet 2hp units and move onto a Clearvue, Penn State or Oneida that are at least 3hp. You will have to spend more on the hoses and ducts ahead of time but why go with a 2hp or less now, if you’re thinking you might be doing ducting later on? It will be more expensive to buy underpowered and keep tinkering and doing mods but in the end, it’s cheaper to just get the largest one you can afford and be done with it.

View clin's profile


930 posts in 1145 days

#4 posted 05-25-2016 04:53 PM

I’ve read comments along the lines of,

Step #1: Shop vac
Step #2: HF DC
Step #3: Get 3+ HP DC

Looks like you’re about to take step #2. I’m still on step#1.

Of course most of us have to make choices where we spend our money. So always getting the “best” is not practical.

Will a 1.5 HP system do for the next 5 years. The length of time you’ll use it doesn’t relate to how well it will work, aside from wearing out.

Controlling dust is sort of a battle that can never truly be won, and there are different ways to approach it. According to Bill Pentz, without moving at least 1,000 CFM at the tool, you will not collect the bulk of dangerous, fine dust. And to do that you need a bit more then 3 HP and properly designed blower and cyclone.

So if you don’t do that, you take other actions like wearing a respirator. An ambient or room filter becomes more important, though without modification to use HEPA or equivalent filters, it has limited value with the really fine dust. Blowing out the shop more often is needed. Perhaps increasing ventilation of the room.

Myself, I’m still on step #1. Mostly because I’m not sure how much actual wood working I’ll ultimately be doing. If I feel the need to go beyond the shop vac, I plan to skip step 2 and go straight to step 3, and get it done once and for all. That will be less expensive in the long run.

But obviously, a low power DC with good filters, will be better than the shop vac.

If I were making dust 15 hours a week and feeling the need to blow the shop out weekly, I’d spring for the large system if I could afford it. Don’t for get ducting adds significantly to the total cost.

-- Clin

View brtech's profile


1042 posts in 3072 days

#5 posted 05-25-2016 07:58 PM

I look at things a little bit differently, but come close to most on everything but one aspect.

All the DCs, including the HF DC do the same basic thing: get chips and dust out of the tool and collect it.
How well they do that depends on a bunch of things, but the big one is Cubic Feet Per Minute of air. Our usual suspect expert is Bill Penz. Read his stuff, please. He has a very definite point of view, but he also has a lot of facts. The facts lead me to the conclusion that you can’t really get the fines out of the tool without 800 CFM+ of air. If you have less than that, at the tool, then too much of the fines are left in the air and it’s dangerous to your health. There are tools that measure this, there is a standard for particle counts, and Bill’s data holds up. I’m not aware of anyone claiming he is wrong; people just think he shouldn’t be quite so strident about it.

The thing is, you need 3-5HP and a really big impeller to get that many CFM on a real system, measured at the tool. Anything in the 1-3HP range can’t generate enough suction.

Then you need something else: a filter, unless you exhaust to the outside. The problem with exhaust to the outside is that you are dumping 800+ CFM of conditioned air outside, seriously denting what your heating and cooling system can deal with, and running your costs up. So most folks have a filter. You need, everyone agrees, 99.99% or so of particles under .5 micron filtered out. Bags don’t usually do that, so you usually need a canister filter.

Now, you can lose CFM lots of ways, the most common being bad ducting, but that’s something that isn’t all that hard to get right. You can also lose it by having a clogged filter. The filter won’t let more particles through, but it causes enough back pressure that you can’t keep the air speed up, and thus don’t get the dust into the system. So we have to clean our filters every once in a while.

To help some, we use separators. There are lots of designs for separators, including the angled ramp that is built in to most of the low end DCs, a cyclone which is part of most large DCs and a Thein baffle. All the separators do is dump dust and chips in a bag or barrel before they get to the filter. By doing that, you increase the time before you have to clean the filter. They don’t actually get more dust out of the tool. In fact, because every separator negatively affects airflow, they all DECREASE the CFM. If you have 5HP and you have a big impeller (and a good ducting system and a good filter), then you have some CFM to spare and it’s good to get as much junk out of the air stream before you send it to the filter. They also don’t get much of the fines: they all rely on the fact that the heavier stuff drops while the lighter air floats.

But if you don’t have 5HP and a big impeller.., then the separator gets you more bad stuff in the air, for the convenience of not having to clean the filter as often. Every separator negatively affects CFM, and degrades system performance at getting the fines out of what you breathe. What is the price to your health of that convenience?

But not everyone can afford the Clearvue or equivalent systems that really can deliver 800 or 900 CFM to the tool. What then? Well, more is better. Every particle the filter gets is a particle that won’t go in your lungs. If you believe that you will never be able to afford something that will keep you healthy, then get a cheap DC that picks up the big stuff, use an air cleaner to avoid spreading dust in the rest of your house, and wear a respirator when you work.

If you think that you will just have to save up the bucks to get something that actually is safe, then, my personal opinion is to get the HF DC, upgrade to a Wynn .5 micron filter, a short length of flex duct, and no separator other than the ramp built into the DC. Then start saving for the good DC and use the respirator until you can afford it. It takes 30 min max to mount the Wynn, so it’s not a hit to your woodworking time.

I don’t think the real 2HP or 3 HP systems that cost a lot more than the HF+Wynn are a worthwhile investment, because they put off the point where you can afford something that actually works.

I don’t think any form of separation beyond the ramp is a good idea for the convenience of lengthening the time between filter cleanings. It robs an already underpowered system of CFM for convenience. This is a health issue, nor an appearance issue. If you have more CFM than you need, then a good separator is great. Bill thinks many cyclone designs are inadequate, but some testing has been done, and there are some cyclone designs that as good or better than the Clearvue which is Bill’s design.

If you want to know, rather than guess, what is happening in your shop, buy or borrow a particle counter.

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Fred Hargis

5097 posts in 2642 days

#6 posted 05-25-2016 08:08 PM

I suggest you read brtech’s reply again, he has some sage advice in there.

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

View TonyJKent's profile


5 posts in 892 days

#7 posted 05-25-2016 09:59 PM

Thanks for the input everyone, I appreciate it.

View Kelly's profile


2092 posts in 3093 days

#8 posted 05-26-2016 04:48 PM

I have to take exception to that smaller units will not gather fines. They will, if collection at the pickup location is done well.

For example, I have my little 1-1/2 horse (Jet canister) at my band saw and sanders (drum-disk, oscillating spindle and 97” belt). Merely by putting a piece of vinyl at the bottom back of the belt of my 48” sander, collection went way up, since air was no longer drawn from an area where no dust was produced.

My band saw does fair. However, running down the side of a board is guaranteed to produce a lot of dust the throat collection cannot pick up. For the band saw and the sander, taking advantage of the second port and using a presentation tripod to support the end of a second hose near the sawdust producing area knocks the airborne dust to minimal amounts.

My router table does so well with two ports (upper and lower), it’s not worth cleaning the table after a molding run.

My sanding table was all but worthless. I added adjustable posts to each of the four corners and draped nylon over the table. Again, this stopped air from being drawn [by my three horse] anywhere but the front, where I’m working

The main point of this is, focus on design of your pickup at the tool first. Without a good design there, a three horse isn’t going to do any better on some tools than a one horse with a good hood at other tools.

View brtech's profile


1042 posts in 3072 days

#9 posted 05-26-2016 05:03 PM

Are you measuring your airflow at the tool and/or the particle count for small particles? The later is the real deal; none of the other stuff really matters – if you are measuring very low particle counts, then what you have is working.

According to all the work I’ve seen, you need around 800 CFM at the tool to get the fines. And, BTW, you can’t see the dangerous particles, they are too small. You can measure airflow with inexpensive equipment. If you are measuring 800 CFM plus or minus, then probably, your system is clearing the fines.

But if you claiming that you are getting 800 CFM at the tool from a 1 1/2 HP dust collector, I’m pretty dubious.

If all you are claiming is that your setup creates little visible dust, that’s very nice, but wear a respirator.

View Kelly's profile


2092 posts in 3093 days

#10 posted 05-26-2016 06:21 PM

I’m confused, why would light fines project farther than the big stuff and be the last to be collected?

When I stand in front of my sanding station and drop dust, I can see the air flow down, into the table. If I’m sanding and not projecting the fines at the speed of light, it would seem they no where to go but with the air movement and into the collection system.

My three horse does kick butt on my horse and a half, or my pathetic 1 hp. Still, three or even five horse trying to grab all the air in what could be pictured as several square feet of wall area around where I’m working, versus a horse and a half trying to draw from a single square foot has to make for some pretty heavy competition.

The big hoods they sell for lathes are pathetic for collecting anything but fines. By building a hood from PVC and cutting it so it wraps around the turning, without interfering, goes VERY far to collecting much of what is tossed off by the knives.

All this is not to say a bigger system (hp and impeller) with a thousand or better CFM isn’t better. It is better. Instead, I’m saying you can take anything Bill puts out and make it very inefficient, if you don’t focus one the hood (e.g., reducing it to as small as needed to grab everything a give machine is putting off).

View brtech's profile


1042 posts in 3072 days

#11 posted 05-26-2016 06:34 PM

I will certainly agree that you can make any DC system not work by having insufficient collection at the source. Agree that just because you can deliver 1000CFM of suction to the port on the machine doesn’t mean you can get all the fines the machine creates.

What I am saying is that the work that has been done indicates that, unless you have something like 800 CFM, you can’t clear the small particles that are the dangerous ones. The most efficient hoods or collection systems won’t keep you safe unless you have around 800 CFM.

So 800 CFM and lousy collection = unsafe
less than 800 CFM and great collection = unsafe
800 CFM and great collection = safe

I suppose it goes without saying that less than 800 CFM and lousy collection is unsafe :)

You can argue that really lousy collection and more than 800 CFM could be worse than less than 800 CFM and great collection. Depends on what the real air speed is. It’s easy to see that if the open area of the port is large, that to get 800 CFM you need a lot more linear FPM than if the open area is small.

But neither is safe.

View clin's profile


930 posts in 1145 days

#12 posted 05-26-2016 07:06 PM

Keep in mind that collecting the dust is really an airspeed issue not a CFM issue. It just translates to CFM for practical applications like a table saw. A table saw spews dust over a relatively large area so you need the large volume (CFM) to ensure you have the needed airspeed to counteract the high speed of the particles.

But if the dust source is more localized, then a smaller CFM will still get you the needed air speeds.

But air flow is tricky business, and every tool is going to have it’s specifics. Virtually all of us are using a table saw, and that probably is the one that needs the most CFM anyway. So that’s what you have to design towards.

As far as fine dust getting away, when visible dust isn’t, that’s a good question. I’d have to re-read Bill’s stuff since he probably addresses this. Maybe there’s something in the physics of the cutting that simply causes fine particles to come off the tool much faster.

-- Clin

View NoSpace's profile (online now)


133 posts in 1390 days

#13 posted 05-27-2016 06:00 AM

“I’m currently using 2.5” shop vac + dust deputy on a cart that I wheel around my shop. Once a week I blow out all the dust from my shop. I have a Jet AFS-1000B air filter hanging from the ceiling which helps. My biggest concerns are the fine dust I can’t see that I’m breathing and the fine dust I can see everywhere.”

I recommend the Dylos air quality control monitor, and then you can see exactly how big your fine dust problem is. I have some issues with the Pentz site, even though I think it’s a must-read to become paranoid enough to take dust seriously.

My garage is about the same size as yours and I also have the Jet. Fine dust is extremely easy to get rid of. The Jet on medium keeps the garage air cleaner than the air inside the house while the belt sander runs—with a Fein turbo 1 2/5 ” vacuum for collection. I keep it on low to share current with the bandsaw, but even 8” of resaw struggles to keep any appreciable fine dust in the air longer than a couple minutes.

The problem tool is the table saw. Even one moderate cut will put the Dylos at 3x a half hour on the bandsaw. But I just have a contractor saw, and there is no way in hell a really nice DC is going to help that much because of the air flow through the tool. I’ve seen plenty of complaints about the dust hoods on even really nice table saws. So to me it all comes down to what it will take to fix the dust problem of a table saw because all the rest don’t register much with the Fein + Jet going.

The solution is I always wear a Nishon face mask when cutting on the table saw (and a few other operations just to be safe) and keep it on until the Dylos tells me it’s clear. According to the Dylos, there have been dry days where the natural dust in the air is higher than when using any tool other than table saw. Vacuuming puts as much dust in the air as most operations. The time I blasted dust from the regular family vacuum fixing a problem with it one day put 8x the dust of my worst tablesaw cuts in the air.

Anyway, the one thing I don’t understand about some people around here is there’s lots of elaborate dust collection projects that go on but folks tend to balk at dropping 200$ to measure the problem they’re trying to solve with hundreds or thousands of dollars and god knows how much time. I’d start with the tool that can actually measure the problem you want to solve, and take it from there.

View TonyJKent's profile


5 posts in 892 days

#14 posted 05-31-2016 04:12 PM

I ended up buying 2 HP Grizzly Cyclone (G0440) . Working on installing it now – a couple of parts were damaged. I’ll let you know how it goes.

View RobS888's profile


2494 posts in 1994 days

#15 posted 05-31-2016 05:29 PM

I ended up buying 2 HP Grizzly Cyclone (G0440) . Working on installing it now – a couple of parts were damaged. I ll let you know how it goes.

- TonyJKent

Did you get the stand or are you mounting it yourself?

-- I always suspected many gun nuts were afraid of something, just never thought popcorn was on the list.

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