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JacksonMaberry

Shop Air Filtration: Hanging units vs "air purifiers"

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Hey gang,

I'm concerned about dust in my space. Between my shopmate's alberti disc sander, our occasional hand sanding, and everything else, I feel there is too much particulate in the air for health and for varnishing. I offered to buy a hanging unit for the shared space, and he complained about the bulk/noise. 

He owns the building, so ultimately it's his call, but I'm not happy my concerns are being dismissed over shop aesthetics. We are currently discussing how to meet in the middle.

One option is to use one or two of the HEPA air purifiers common in home use. Their 0.3 micron rating is technically better than the 1 micron rating of the hanging models, but they do move much less air per hour through the shop. 

Anyone have experience with using HEPA air purifiers in a shop context? 

 

Thanks,

J

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Hi Jackson, i have one of the hanging units in the machine room where i do all the sanding. It is pointless to use it all the time, because of the air circulation additional dust is raising from the floor and other surfaces. Therefore i start the filter device in the night after work and run it for about 6 hours and leave it at least another 3-4 hours for settling. So, in my case noise wouldn’t be a problem at all.

 

 

 

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Yes, I remember that discussion. Thanks for sharing.

I have no experience with air purifiers but use a cyclone dust collector with HEPA filter. Maybe that is an option as well? Get a smaller unit and try to collect as much dust as possible at the source. Then run the dust collector for a little while with open port to function as an air filter. If your room is small the time needed to exchange the entire air volume several timed might not be long. Not a quiet option but you would only run it while you work plus the extra time for “air filtration” after you are done.

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IMO your mate needs to get his priorities straight. 

I worked in a shop where they were using a bandsaw and sander with no dust collection at all, and it was a constant niggle in the back of my mind.. because it's not like that shop is going to still exist or those people still alive in the future when I get lung cancer.

If I were you I would insist on an air filter and dust collection cyclone system. 

If he doesn't want to put in for it, pay for it yourself then take it with you when you go somewhere else.

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3 minutes ago, David Hart said:

IMO your mate needs to get his priorities straight. 

I worked in a shop where they were using a bandsaw and sander with no dust collection at all, and it was a constant niggle in the back of my mind.. because it's not like that shop is going to still exist or those people still alive in the future when I get lung cancer.

If I were you I would insist on an air filter and dust collection cyclone system. 

If he doesn't want to put in for it, pay for it yourself then take it with you when you go somewhere else.

He's a good guy, just has a different view on the situation and I can sympathize. We don't have any power tools other than a drill press in the shop. The big guns (bandsaw, etc) are in a separate building hooked to a cyclone. But dust comes from everywhere - people, even the low grade sanding we do by hand or with his alberti, etc. I have ordered the machine I linked to. It's capable of cycling the air in a shop our size four times an hour, filtering to .3 microns. I'll report on its efficacy after a month - because if I don't like it by then I can return it for a full refund. 

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16 minutes ago, JacksonMaberry said:

We don't have any power tools other than a drill press in the shop. The big guns (bandsaw, etc) are in a separate building hooked to a cyclone. But dust comes from everywhere - people, even the low grade sanding we do by hand or with his alberti, etc. 

I might suggest, respectfully, that you are being a bit obsessive. The kind of dust production you are describing seems very standard, if not ideal. We work with wood. There will be wood dust. I may be wrong, but I find it hard to picture producing enough dust with your hand tools to create a health hazard. 

As far as varnishing goes, I mitigate the effect of dust in my (relatively) small shop by cleaning at night, setting up everything I will need for varnishing, and leaving. Then first thing in the morning, before I touch one f**king thing, I varnish. Not a lot of dust.

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11 minutes ago, arglebargle said:

I might suggest, respectfully, that you are being a bit obsessive. The kind of dust production you are describing seems very standard, if not ideal. We work with wood. There will be wood dust. I may be wrong, but I find it hard to picture producing enough dust with your hand tools to create a health hazard. 

As far as varnishing goes, I mitigate the effect of dust in my (relatively) small shop by cleaning at night, setting up everything I will need for varnishing, and leaving. Then first thing in the morning, before I touch one f**king thing, I varnish. Not a lot of dust.

That's fair, I'm not offended. I am pretty fussy about stuff in general. If I worked by myself, I would have enough control over the space that I'd probably be able to get by with your method, but the shop is on my partners property and he is in there at all sorts of hours when I am not. 

I'm also an asthmatic, and since my lungs are kinda jacked up anyway, I might as well go to whatever ends I can to preserve what lung function I've got. I mean, I mask up when actively sanding/scraping or cleaning. That said, if going overboard means fewer nits in my varnish and better breathing, I'll take it. 

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1 hour ago, arglebargle said:

I might suggest, respectfully, that you are being a bit obsessive. The kind of dust production you are describing seems very standard, if not ideal. We work with wood. There will be wood dust. I may be wrong, but I find it hard to picture producing enough dust with your hand tools to create a health hazard. 

As far as varnishing goes, I mitigate the effect of dust in my (relatively) small shop by cleaning at night, setting up everything I will need for varnishing, and leaving. Then first thing in the morning, before I touch one f**king thing, I varnish. Not a lot of dust.

Ah, sorry I was of the impression some substantive amount of sawdust was being produced. 

If you are producing enough sawdust to be a worry and your not doing it with power tools... perhaps revising your working methods will help?

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24 minutes ago, David Hart said:

Ah, sorry I was of the impression some substantive amount of sawdust was being produced. 

If you are producing enough sawdust to be a worry and your not doing it with power tools... perhaps revising your working methods will help?

I appreciate your thoughts, but I don't believe wood dust is the main culprit in this case. There a lot more sources of particulate out there than wood. Our clothes, our skin, the clothes and skin of our customers, environmental dust that comes in with us and our customers from outdoors, the materials of the shop itself, which is a very new building and therefore giving off a lot. Let me give you a visual example of what I'm talking about. Attached is a photo of the intake filter on my new lightbox after roughly 20 total days of operation. You'll find that there's quite a lot of dust in it, but very little of it from wood. 

IMG_20200315_173304.jpg

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What about the Molekule air filter? Extremely effective, and actually destroys some of the pollutants, rather than trap like a HEPA type, and apparently goes to 0.3 micron, so much better for your asthma.  List for the big one is $800., apparently. https://molekule.com/air-purifiers

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4 hours ago, JacksonMaberry said:

 Let me give you a visual example of what I'm talking about. Attached is a photo of the intake filter on my new lightbox after roughly 20 total days of operation. You'll find that there's quite a lot of dust in it, but very little of it from wood. 

IMG_20200315_173304.jpg

Jackson, unless a lot of ebony work is being done, that black color is highly unusual. I'd suggest figuring out where that is coming from (black mold?, soot from a malfunctioning unvented heater?), before worrying about minor amounts of spruce or maple dust.

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Jezz & 1337, thanks for the suggestions! Those are both fantastic units by all accounts. The one I went with tied the Molekule in a head-to-head and beat the Dyson by a narrow margin in a different test, for a few hundred less. I'm going to give it a 30 day trial before trying something else.

DB, thanks for chiming in. Compared with a large shop, I'd say very little ebony work goes on. My partner is a bowmaker, so most of the ebony stuff happens on his side, making frogs. Obviously I make nuts and saddles, dress boards, shape pegs, but we are a small rural shop so it's not like we're doing many ebony operations per day. For what it's worth, the color of the dust trapped in the filter was more grey than black, and when I gave it a sniff didn't smell moldy/musty. Just... Dusty! I will poke around the HVAC and see what's up, for sure, however.

I'd like to state for the record that my main worry isn't wood dust - it's just generalized particulate in the air, regardless of source. I want the air properly scrubbed out, is all. 

Thanks for the thoughts and ideas, please keep them coming.

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For those who have a forced-air system, this is what I have been using for about 20 years. It requires some custom ductwork to install, since it is much larger than a conventional furnace filter.

LINK

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Hi Jackson,

If you are worried about dust, anything you can do to reduce it helps. It is a legitimate concern. You mentioned that you wear a mask at times... masks are your final dust collector, just before your lungs.

My shop is a funiture shop mostly and I have three dust collectors and a spay booth. To clear the air quickly, I run the booth fan for a bit. I also have a Delta air filter above the sanding area which helps somewhat but is loud.

If you have the climate to pressurize the shop, in out with a fan to ensure a clean airflow at all times is good, watch the humidity.

A damp mop over the floor is an easy way to "freeze" dust. Vacuum often, don't forget the mask.

I think that you are wise in your concerns regarding a safe, healthy work environment. I have developed sensitivitys to certain woods over the years.

Thanks,

Pete

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On 3/15/2020 at 7:39 PM, JacksonMaberry said:

He's a good guy, just has a different view on the situation and I can sympathize. We don't have any power tools other than a drill press in the shop. The big guns (bandsaw, etc) are in a separate building hooked to a cyclone. But dust comes from everywhere - people, even the low grade sanding we do by hand or with his alberti, etc. I have ordered the machine I linked to. It's capable of cycling the air in a shop our size four times an hour, filtering to .3 microns. I'll report on its efficacy after a month - because if I don't like it by then I can return it for a full refund. 

Perhaps you could run a collection pipe and remote power switch from the cyclone in the other building to your local work area to suck up dust as you make it. It would be quiet and only require a small cash outlay for the collection pipe / hose and some wire and a switch.

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Another option:

If one doesn't live in an area where heating and cooling expenses are horrible, just run an exhaust fan. Wood dust (and wood) will quickly degrade in most outdoor environments.

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Good thoughts folks, thanks. The cyclone is on the opposite side of the property, unfortunately. The exhaust fan is a viable option, but at the same time wood dust is only a small part of my dust problem. 

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I have a filter similar to the Coway you posted earlier. It's in my bedroom, and there it does fine, but because it's made for home, the fan is quiet, and you can translate that to not having the kind of air movement you need for what you're doing. Making the bed is enough to make the thing go into red alert for 30 minutes. I can't imagine that you'd notice any difference at all in a workshop--mine would be running full blast all the time and never catch up. Also, since it doesn't really create air flow on it's own, it's only going to catch what's going by. On the other hand, a real shop system is going to be moving a lot of air into itself. Even then, it's going to be going past you on its way out. As others have said, the real solution it to catch dust at its source.

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11 minutes ago, Michael Darnton said:

I have a filter similar to the Coway you posted earlier. It's in my bedroom, and there it does fine, but because it's made for home, the fan is quiet, and you can translate that to not having the kind of air movement you need for what you're doing. Making the bed is enough to make the thing go into red alert for 30 minutes. I can't imagine that you'd notice any difference at all in a workshop--mine would be running full blast all the time and never catch up. Also, since it doesn't really create air flow on it's own, it's only going to catch what's going by. On the other hand, a real shop system is going to be moving a lot of air into itself. Even then, it's going to be going past you on its way out. As others have said, the real solution it to catch dust at its source.

Thanks for this. I am working on pinpointing the principal sources of dust. I am also probably worrying more than is necessary - it's a habit. I have successfully varnished in dustier places, like the IU shop, which probably hadn't been cleaned in three decades by the time I was there. The oversized HVAC unit in our shop cycles the air about 6x an hour as it is, and we have a serious filter in it. Maybe in combination with the Coway it could make a difference, but it remains to be seen. I've already ordered it, so I'll give it a shot and if it's as unsuitable as you're suggesting, I'll return it. I have a month to trial it. In the mean time, I continue to work on mitigation.

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Sometimes we use the same terms for different things. Dust particles are relatively large.  This is the stuff that settles on horizontal surfaces and messes up our varnish.  The suspension time for these particles are short.  Because of their size, we are able to expel these particles from our lungs.  Therefore, dust particles are not normally considered a long term health hazard.  I'm only referring to particle size, not whatever the particle are made from.  

Airborne particulates that are considered a long term health hazard are < 2.5 microns in size.  They pretty much stay in suspension.  They are so small that they get stuck in your lungs and can accumulate over time.  If you are generating dust, you are also generating airborne particulates. 

Jackson just posted while I was writing.  With an air exchange of 6x per hour, the PM < 2.5 concentration in the shop should be approximately the same as the ambient air outside the shop.  Is that good?  It depends where you live.

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6 minutes ago, Jim Bress said:

With an air exchange of 6x per hour, the PM < 2.5 concentration in the shop should be approximately the same as the ambient air outside the shop.  Is that good?  It depends where you live.

Pretty bad in Walla Walla in the Spring-Summer. Starts with pollen, ends with glyphosate-infused wheat stubble dust / loess. When the forests around here burn, the smoke settles in the valley, adding insult to injury. What the hell was I thinking moving back here? =P

Miss ya Jim! Hope you're well, my friend. 

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2 hours ago, JacksonMaberry said:

Pretty bad in Walla Walla in the Spring-Summer. Starts with pollen, ends with glyphosate-infused wheat stubble dust / loess. When the forests around here burn, the smoke settles in the valley, adding insult to injury. What the hell was I thinking moving back here? =P

Miss ya Jim! Hope you're well, my friend. 

Meh, Walla Walla's not too bad.  Although today's readings are probably skewed by everyone staying home.

https://aqicn.org/city/usa/washington/walla-walla/12th-st/ 

To bad your on the wrong side of the continent.  I finally found a bottle of the añejo tequila a certain tone judge from Mexico introduced me to.  Because the alcohol % will kill covid-19 we could say the tasting is for medicinal purposes. ;)

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