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Forum topic by Daveoffinland posted 08-03-2020 08:25 PM 436 views 0 times favorited 13 replies Add to Favorites Watch
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Daveoffinland

3 posts in 51 days


08-03-2020 08:25 PM

Topic tags/keywords: dust collection

Hello everyone. New to woodworking and making first post here.

After reading about dust collection in posts here and on Bill Pentz’ blog, I understand that DC (particularly fine dust collection) is paramount in shop set up. I also have allergies, so inadequate DC could quickly ruin my new hobby.

Since my shop is small (half a two car garage) and I’m still figuring out how I want the tools set up, I’ve decided on a mobile system that I can connect directly to the tool I’m using. As I understand it, the shorter the run the more efficient the DC.

So far, I have purchased the 2HP Harbor Freight dust collector, a powertec 70001 bag for the HF DC, and a Wen air filtration system. I also plan to wear a 3M dual cartridge respirator while working.

Do you think this set up is sufficient for the time being? Can I get by without adding a cartridge filter to the HF DC? Should I work with the garage door open and have an air mover pushing the dust outside (painful but possible here in Houston)?

Thanks in advance for your thoughts.

PS. Would it make sense to buy a particle meter like this one?


13 replies so far

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becikeja

1131 posts in 3661 days


#1 posted 08-03-2020 10:56 PM

I’m sure many will weigh in here. I have asked multiple questions on the site as well. Here are my observations. The dust collection at the tool is the key. Make sure you have good dust ports and dust hoods. If you get this right, then you can move to the bag/canister/cyclone. and spend as much money as possible….......... Until recently I wrapped a moving blanket around my 30 micron dust bag and it did just fine. It was amazing how much fine dust particles collected inside the blanket, but it worked well. It was a mess when it came time to empty the bag so I finally upgraded to the canister (15 years with the moving blanket, what can I say I’m cheap). But if your tool throws dust into the air it doesn’t matter how much you spend at the dust collector. Personally I think most of these conversations are spent at the wrong end of the hose….

-- Don't outsmart your common sense

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ibewjon

1937 posts in 3641 days


#2 posted 08-04-2020 01:21 PM

From all the conversations regarding how to up grade the HF DC to make it work, and how the price is about the same as a real DC with the pleated filter, I would return it if you can and buy a better machine. The pleated filter is a necessity. Griz has a 1 micron filter. The 30 micron bags are only chip collectors, and create more dust. I had a 30 mic bag, it was horrible. I converted to a jet pleated filter, and have almost zero airborne particles. A ceiling hung air cleaner completes the setup. The moving blanket restricts airflow, which is necessary for good collection. With enough airflow, you get much better suction, and much better collection at the machine. There are as many options and opinions on this subject as there are LJ’s.

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Daveoffinland

3 posts in 51 days


#3 posted 08-04-2020 02:10 PM

Thanks to becikeja and ibewjon for responding. Does anyone have experience with the powertec 70001 bag? Doesn’t it act like a 1 micron filter?

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ibewjon

1937 posts in 3641 days


#4 posted 08-04-2020 03:24 PM

That is what they claim. My view is that to get enough air volume and velocity, the air needs to escape from the bag. A pleated filter has more area to allow the air out. I looked at American Air Filter, and their bags were much bigger than powertec. I don’t see how that bag can allow enough air flow to work. Any superfine filter can reach the filtration spec, but without enough velocity to keep dust and chips suspended, and enough volume of air movement to collect the dust at the source, it won’t work for shop use. I could be very wrong, but if it’s too good to be true,( good filtration, small size, and small price) it probably is. For the $30, it is not a large investment to try it. The dylos meter has a good reputation, but I would put that money toward a better system.

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AndyJ1s

414 posts in 603 days


#5 posted 08-04-2020 04:45 PM

The above advice to worry about dust collection at the source is sage.

However, collecting all that dust, and sending it through a filter that spews out the most harmful (smallest) particles, is almost pointless.

Preferably, you want HEPA rated (at least 99.97% efficient at 0.3 micron) filtration. That doesn’t happen with any bag filters of which I am aware.

To avoid having to clean the filter every time you turn around, you will want an efficient cyclone separator. Beware short stubby cones (of which the JET Vortex is the extreme) on cyclones, and go with the tall, slender cones.

Beware of collectors with cartridge filters that provide an external handle for internal paddles to clean the filter. Paddles dislodge large debris that would have been caught by a good cyclone separator. Fine dust is removed with low pressure compressed air, from the outside in, preferably at a shallow angle to the filter membrane.

Also, beware of filters spec’d as “99.99% efficient at 0.2 to 2 microns” or similar. That spec does not mean that they are that efficient at every size particle in that range; it means they are that efficient with a mixture of particles between 0.2 and 2 microns. Notice they seldom specify the mass distribution of particle sizes in the test dust sample. The filter could be passing 100% of 0.2 micron particles, but if those particles make up less than 0.01% of the total mass of the dust sample, voila, they still meet the overall efficiency spec! Specs don’t lie, but…

Especially if your DC is not HEPA rated, you should wear a mask that is, and also seals effectively against YOUR face. Good masks are sometimes heavy, and often hot.

Good dust collection is not cheap, but neither is your health.

-- Andy - Arlington TX

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clagwell

293 posts in 641 days


#6 posted 08-04-2020 05:24 PM

Since you already have the HFDC and the Powertec bag Just try it, like ibewjon suggested. A pleated filter may have more media are than a bag initially but it will have a lot less once the pleats fill up with dust. Without some kind of separator you need to clean the filter after filling the bag about halfway to keep full flow.

I do recommend some kind of dust monitor. The Dylos you linked is fairly old technology. See post #7 and following in this thread for what I consider to be a much better choice at a lower price. You can get it on Amazon but I like Ebay or Aliexpress. Just use appropriate caution choosing vendors.

There’s no need for HEPA on that DC. The DC won’t collect anywhere close to 99.97% of the fine dust so that kind of filter is a waste and could actually yield worse air quality because of it’s greater flow restriction.

-- Dave, Tippecanoe County, IN --- Is there a corollary to Beranek.s Law that applies to dust collection?

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Bill White

5302 posts in 4808 days


#7 posted 08-04-2020 07:21 PM

I’m a HF owner too, and spent the money on GOOD, felted collection bags. I use 2 bags on the unit (top and bottom), and can’t complain. Sure, there is some escape, but with an ambient air cleaner and adequate ventilation I’m not at all unhappy with the setup. Some will poo pooh the unit. Let ‘em. It works for me.
I hook it up to the machine in use.

-- [email protected]

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clagwell

293 posts in 641 days


#8 posted 08-04-2020 08:09 PM



I do recommend some kind of dust monitor. The Dylos you linked is fairly old technology. See post #7 and following in this thread for what I consider to be a much better choice at a lower price. You can get it on Amazon but I like Ebay or Aliexpress. Just use appropriate caution choosing vendors.

- clagwell

Oops, I left out the thread link. Here it is.

-- Dave, Tippecanoe County, IN --- Is there a corollary to Beranek.s Law that applies to dust collection?

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AndyJ1s

414 posts in 603 days


#9 posted 08-04-2020 08:28 PM

HEPA-rated filters often require more surface area than poorer filters, so that they can pass equivalent volumes to poorer filters, without hindering the flow rate, or collection ability, of the collector. To keep their physical size somewhat comparable, they usually have finer pleats, which would clog more quickly if not for pre-separation by a good cyclone.

A good air cleaner (or two or more) in the shop can compensate somewhat for inadequate collection and filtration.

The dust collector gets but one pass at the dust laden air before your lungs (and the air cleaner) do.

But because an air cleaner gets multiple passes at the air in the shop, it need not have HEPA quality filtration to achieve similarly efficiency, even on 0.3 micron particles, for the air it filters multiple times over.

However, few air cleaners move the air sufficiently to keep most such particles suspended, so they settle out on surfaces, to be whisked back into the air when humans or objects move near them. This can be somewhat compensated with additional circulation fans, ventilation, etc.

So the air cleaner competes with your lungs to see which traps the most particles out of the shop air. The air cleaner will certainly win the contest, but by how much?

Good dust management is not cheap, but I bet there are plenty of SawStop tablesaws and other expensive machines in hobby shops with poor, cheap dust management.

-- Andy - Arlington TX

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clagwell

293 posts in 641 days


#10 posted 08-04-2020 08:45 PM

The dust collector gets but one pass at the dust laden air before your lungs (and the air cleaner) do.

- AndyJ1s

That’s an oversimplification. Whatever is coming out of the filter is diluted and gradually increases the concentration in your shop at a rate affected by your shop’s total volume. The dust collector does not do just one pass but, like an air cleaner, continuously recirculates and cleans the air. That is, the ambient dust is being collected at the same time as the new dust.

There’s really not much advantage to having a filter efficiency that a lot better than your collection efficiency.

-- Dave, Tippecanoe County, IN --- Is there a corollary to Beranek.s Law that applies to dust collection?

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Daveoffinland

3 posts in 51 days


#11 posted 08-07-2020 03:03 PM

Thank you all for your thoughts. They are much appreciated!

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fivecodys

1647 posts in 2484 days


#12 posted 08-07-2020 03:59 PM

An air filtering unit hung up on the ceiling is a must for me. My Cyclone DC system vents its exhaust air outside via dryer vent. My shop is not heated or have A/C so no issues there. Even with a door open and the DC venting it’s post cyclone exhaust outside I am always amazed what the WEN Air Filter catches. It’s the fine dust that is a hazard for your lungs. No DC captures all the dust. I was working on a project a couple of years ago using mahogany. My wife came out out into the garage and noticed the WEN filter right away. I was red from all the mahogany dust. I highly recommend you add a unit like this to your system.

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

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AndyJ1s

414 posts in 603 days


#13 posted 08-07-2020 05:14 PM

Dave,

I suppose how well the dust collector cleans the ambient air in the shop depends on how long you leave it running, and how well it recirculates all the air in the shop.

As an example, a Supermax 1200 CFM air cleaner with a “1 micron inner filter” (no efficiency given), has a 1/5 HP motor that draws under 5 amps at 120V, and emits under 60 dB of noise.

As another example, a Jet single stage dust collector (with 98% efficiency at 2 micron) with 1100 CFM uses a 1.5 HP motor that draws 11 amps at 120V, and emits “70 to 80 dB” of noise.

If a DC system has many inlet ducts, all open, it might do a fair job of recirculating the air throughout the shop. If it has only one inlet (open, but buried inside a machine), it likely will not do an adequate job of recirculating the shop air, and thus does not recapture the dust collected, but spewed from the DC’s filter.

Since most users would not want to go to the trouble of opening all the other blast gates in their shop, let alone continue running the noisy DC long enough to clean the shop air, I dare say that a DC would not do a good job of re-capturing the dust spewed from its own poor filter.

Even if it did, a better filtering DC would do it better and quicker.

-- Andy - Arlington TX

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