Air Purifiers-Do they really help control the dust? Trying to prevent fine Dust

[David Ruhland]

I have a 20x50 workshop. My "sawroom" is 20x20 and my tools are connected to a Jet Vortex Dc1100 RCK (has canister and Vortex) .

I have doors i try to keep closed to prevent fine dust from heading into the other part of the shop when sawing.

If i purchased one of those fancy hang from the ceiling air purifiers would that help prevent the fine dust from settling allover the "sawroom"?

I have been doing a lil research and am i correct in reading i need to have one that exchanges the air every 10 mins or something like that?

And finally recommendations of those fancy lil guys that hang from the ceiling? I see lots of them at my Rockler store....ie Jet Rikon, etc...

[Ted Derryberry]

I don't know that you're going to prevent all the fine dust from settling, but they definitely make a difference. Mount it to one side of the room so the air will circulate better. I have a Jet that I've been happy with, but if I were buying one right now I'd get a Grizzly and save some money. I run mine on low speed whenever I'm in the shop and bump it to high speed if I do something that creates a big cloud of dust. You can literally see the dust disappearing out of the air. I buy the cheap furnace filters from the big box and vacuum the face of them several times and change them when they start looking ragged. No way I'm paying the price they ask for the factory filters. My shop is roughly the same square footage as yours.

[Phil Mueller]

My shop is much smaller than yours. I have the Rikon from Rockler that is on a rolling cart. I pull it next to the work when sawing and let it run for awhile after. There is still a little fine dust settling here and there, but it made a huge difference. The proof is in the filters. It does collect a lot.

[Aaron Conway]

They don't make the shop dust free but certainly do make a big difference. I do the same as Ted and have it running all the time on low (it comes on with my shop lights) and then crank it up when sanding, cutting mdf, etc.

[John K Jordan]

My experience is the air filters do make a difference in clearing out the air but it does take some time. I would wear a good respirator when making dust and working after making dust then leave and let the filter clear the air.

I use a Dylos particulate air quality monitor which actually measures the quantity and size of the dust particles floating around. This shows significantly better air after the filter is running for an hour or so. Such a monitor eliminates all guessing and hoping. https://www.amazon.com/gp/product/B004AWEG0Y

Note that the air filter must be installed properly to get good circulation around the room since it can't filter air that it can't move. They come with specific instructions.

JKJ

[Bill Adamsen]

My shop volume is much larger (15,000 cu ft) so I have a 900 cu ft/minute shop-built filter as designed by Bill Pentz (http://billpentz.com/woodworking/cyclone/air_cleaner.cfm). It works well for clearing the air, though I don't have much to compare it with. I have never owned a ceiling hung air filter. I can't answer your question about settling dust. The assumption is that it helps. I regularly clean all surfaces in the shop including those at height (tops of DC ductwork and light fixtures for example) to manage dust and try to maintain as healthful an environment as possible.

Dust management is clearly one of, if not the top health concern facing woodworkers.

[Keith Hankins]

All will help. Rather than worrying about dust on the tools, worry about COPD and breathing. I have one don't use all the time as i should but yes it will help. One thing I did find out, and these should run all the time, is find out the DB rating of the machine. Get as low a DB unit as you can. Mine is a delta and the sucker is loud. Also, mount in an area against a wall to generate an air flow to keep the dust moving.

Generally the smaller the micron it will filter and the quieter it is will drive the cost. I saved a tad on $$ by getting the delta and now know why. Wish I'd sprung for the quieter one. Buy once cry once.

I'm going to be moving in about 2 years, and I will sell mine, and get a better one (quiet).

Cheers!

[glenn bradley]

Like a lot of things that ones that are well made and perform well do better than something else. I have a gable fan in a shop made version that runs a 20" x 20" filter set. Even though it is sub-optimal when compared to something like my dad's JDS, I am always amazed at how much stuff I get out of the filters every few weeks. The filters are empirical proof of what I would otherwise be cleaning up.

10 years ago the JDS 750 was head and shoulders above the herd but, the recent tests I see show Jet and others more or less matching that performance now. The price range for this level of performance still seems to be in the $300 to $400 range.

[Stan Calow]

FWIW, I've heard it said that a ceiling-mounted cleaner will only capture the fine dust that has risen up to the level of the cleaner, leaving lower levels of dust to settle as usual. The corollary to that being a recommendation that they be mounted at the level of your head so that there is more impact on the air you're breathing.

[David Ruhland]

WOW! What great information. I like the idea of building a rolling cart for it. Sound is something i didnt consider either. I was not aware that there are other units out there that are not ceiling mount. i do have a good respirator that i use when sawing. my main focus is to try to cut down on some of the fine dust.

So is the analogy "if a lil is good a lot is better" true here? in other words if i need a 320 CFM would i be wasting my money on a unit that provides 950 CFM

Looking at the Rikon 62-100 https://www.woodcraft.com/products/rikon-3-speed-air-cleaner-with-remote-control-model-62-100

[J.R. Rutter]

The gold standard for dust control is to capture it before it can get airborne. So I would start by trying to figure out how you can accomplish that. I would love to see an actual fan curve for that 1.5 HP 1100 CFM blower...

I bought the Dylos that John recommended and can confirm that it is helpful. I was surprised at the fine dust that was making its way into my office and ended up getting a HEPA filter to keep that air healthy.

[Simon MacGowen]

WOW! What great information. I like the idea of building a rolling cart for it. Sound is something i didnt consider either. I was not aware that there are other units out there that are not ceiling mount. i do have a good respirator that i use when sawing. my main focus is to try to cut down on some of the fine dust.

So is the analogy "if a lil is good a lot is better" true here? in other words if i need a 320 CFM would i be wasting my money on a unit that provides 950 CFM

Looking at the Rikon 62-100 https://www.woodcraft.com/products/rikon-3-speed-air-cleaner-with-remote-control-model-62-100

Anyone who wants a "quiet" air filtration system can build one with an old furnace blower, that can be had for free or at a minimal cost (check your local furnace installation & repair shops).

Mine is also a rolling system built out of a scrap plywood box (Google yo find vast of information on how to build your own purifier).

An AFS is better than nothing, but dust collection at source is still your best defense, followed by a dust mask (suitably rated).

Simon

[Ted Derryberry]

FWIW, I've heard it said that a ceiling-mounted cleaner will only capture the fine dust that has risen up to the level of the cleaner, leaving lower levels of dust to settle as usual. The corollary to that being a recommendation that they be mounted at the level of your head so that there is more impact on the air you're breathing.

I'm going to disagree. They pull the air through and it's going to lift any that's lower. When I have a big cloud like from cutting MDF I can actually see the dust rising to the filter when I turn it on high. You want it higher than your head so you don't bump into it. Of course you can put it over a work table or table saw so you can't walk into it, but then it throws shadows right where you need the best lighting.

[Ted Derryberry]

As for noise, I run mine even when I'm not creating dust because I need the "white noise" to mask my tinnitus. I've found that I can no longer concentrate in the shop when it's not running. Of course I wouldn't want an overly loud one.

[Rod Sheridan]

AS J.R. indicated, the objective is to capture the dust before it becomes airborne.

If you don't, you need to wear suitable breathing protection while in the shop.

I would suggest that you concentrate on collecting the dust at source, for example a table saw will require above and below blade collection.

I simply leave the cyclone with HEPA filter running constantly while I'm machining and for 15 minutes afterwards. I don't have any visible dust and my particle counter shows that the air is cleaner than outside ambient air.

Once you've collected the dust at the source, you won't need a secondary filtering method........Regards, Rod.

[David Ruhland]

AS J.R. indicated, the objective is to capture the dust before it becomes airborne.


I would suggest that you concentrate on collecting the dust at source, for example a table saw will require above and below blade collection.


Once you've collected the dust at the source, you won't need a secondary filtering method........Regards, Rod.

Ya know Rod... the only time i have a real problem is when using the table saw. i will investigate the above the saw collection.. need a portable solution..perhaps one of those on scoops on a stand.

[Jim Becker]

Air filtration systems do pull a healthy amount of suspended fines out the the air in my experience...normal machine dust collection isn't perfect, so any additional help isn't a horrible thing. Since I spray (waterborne) in my shop, it absolutely helps clear the air of suspended, dry finish fines in the air. Mine also serves to help circulate air for better heat distribution at this time of the year. (I have a JDS 2000 model 750 for my ~600 sq ft shop)

[Mike Chalmers]

AS J.R. indicated, the objective is to capture the dust before it becomes airborne.

If you don't, you need to wear suitable breathing protection while in the shop.

I would suggest that you concentrate on collecting the dust at source, for example a table saw will require above and below blade collection.

I simply leave the cyclone with HEPA filter running constantly while I'm machining and for 15 minutes afterwards. I don't have any visible dust and my particle counter shows that the air is cleaner than outside ambient air.

Once you've collected the dust at the source, you won't need a secondary filtering method........Regards, Rod.This all falls into the category of "every little bit helps". The units are not that expensive, and can work quite well, if properly set up. I have three small box fans mounted on the walls the cleaner is not on. That keeps the air moving around the shop to the cleaner. I do not count on "collection at source" to be sufficient, not without a ridiculously huge expenditure of money that most cannot afford.

[Dave Cav]

I have two of the Wen units purchased on Amazon. Considering how much sawdust I blow out of the prefilters every week or so I would say they do a pretty good job. I have a 3 HP cyclone and all of my stationary machines are connected, but whenever I run the widebelt, the edge sander, or do ROS sanding I run the air cleaners. I have two of them, one over the edge sander, and the other over the workbench/assembly table where I do most of my ROS sanding (I use Dynabrades with no vacuum attachment). I have had them for about nine months and I'm satisfied with them. I may get another one for portable use to put adjacent to wherever I'm hand/ROS sanding.

[David Ruhland]

I have two of the Wen units purchased . I may get another one for portable use to put adjacent to wherever I'm hand/ROS sanding.

Thanks for your input.. i am thinking of doing the exact same thing, buying two now and a portable one to put in the proximity of where i am creating the dust. I can buy 3 of them for the cost of 1 Jet 1000

[Thomas Crawford]

I've read a bunch about air purifiers in general (not specific to woodworking), and everything I've read makes me want to have one that I can move around. I'm thinking of something like this:

https://www.amazon.com/AIRMEGA-Smarter-Purifier-Covers-1256/dp/B01C9RI96S/ref=sr_1_7?ie=UTF8&qid=1516827155&sr=8-7&keywords=air+purifier+coway

Seems like a lot of people hang the Jet models in the middle of the room but I think they are supposed to be near a wall to promote circulation.

Are there reviews of the Jet/Grizzly/etc vs. the other models for use in the home or in commercial spaces like cigar bars?

[Brian W Evans]

I agree that these units do collect dust, as evidenced by the filter. However, I remember reading article in FWW(?) that said these units are not much help in keeping the air in a shop clean, and in fact might make things worse. IIRC, the main point of the article was that these units circulate the air, which blows around dust that would otherwise have settled, plus they are not able to capture the really fine stuff that also gets blown around. I looked for the article online (I am a member of FWW online) and couldn't find it - sorry.

That said, I have a JDS that I use (along with a cyclone dust collector and a respirator that I wear religiously). A nice feature to have is a timer or delayed shutoff. I turn mine on when I turn the machines on and set it to turn off an hour or so after the last machine gets turned off. Also, since it is usually located near the ceiling, a remote is very handy.

[Neil Gaskin]

Our shop is just a bit bigger. We have two powermatic air filters. They do make a big difference in my opinion.

[David Ruhland]

Our shop is just a bit bigger. We have two powermatic air filters. They do make a big difference in my opinion.

I assume these are on walls parallel to each other? Does the intake face the same way on each? Dav Cav can you weigh in here please?

[Thomas Crawford]

Finally found some actual data on the woodworking specific machines:

https://www.finewoodworking.com/fwnpdfFREE/011213054.pdf

Is anyone concerned that these aren't HEPA rated? Seems like its just blowing the small stuff around.

[Thomas Crawford]

Any opinions on this article? Not sure when it was written.

https://www.highlandwoodworking.com/woodworking-tips-1605may/dtew/dtew1.html

Seems important to get all the visible airborne dust, but might as well get the super small stuff at the same time.

[Jeff Aubrey]

There is a new product "Box Fan Filter Grip" that consists of 2 silicone bands that are sized to hold a 1 x 20" x 20" furnace filter to a typical 20" x 20" box fan. You can choose different strength filters that suit you best. I have 2 fans in my shop that I hung from the garage door mounting brackets using multiple zip ties. The Box Fan Filter Grips hold the filters securely in place and creates a good seal between the fan and filter. I also have a box fan in my bedroom that I use a Merv 8 or higher filter to remove dust, pollen, and mold spores. I typically sleep 8 hours and so for 8 hours a day I am breathing purified air very economically. I got the box fans at Walmart for under $20 including sales tax and I buy filters 12 at a time online for under $6 each. The Grips were $11.95 per fan and should last a long time. This is the link for the Box Fan Filter Grips https://www.amazon.com/dba-Box-Fan-Filter-Grip/dp/B07F72D436/ref=sr_1_1?ie=UTF8&qid=1532003559&sr=8-1&keywords=box+fan+filter+grip

[Jim Laumann]

Jeff

Could you post a picture of how you have you fans on the door?

[Van Huskey]

We all know 100% collection at the tool is impossible at least with hand fed machines in a hobby shop. My gripe with the majority of the ambient air filters is they have very low MERV ratings. Early on in the thread Bill Adamsen mentioned what I think is the most cost-effective solution for HEPA level filtration in the shop, Bill Pentz design. While you can certainly leave your DC running, as Rod mentioned, and it will be effective it isn't very energy efficient and they are also loud.

Three things I think improve the Pentz design are:

1. Build it only a mobile base. For the times you will be making more fine dust you can move it near you and grab more of what is missed by the DC/vac before it has a chance to infest the entire shop.

2. When you build it onto a mobile base build a frame for pre-filters. Mid-level MERV HVAC filters will reduce the fouling of the HEPA filter and reduce long term costs. You can even use foam AC filters which can be bought in bulk rolls and can be cleaned.

3. Build in a timer so you can let it run for a period of time once you leave the shop. A good choice is the mechanical timers similar to ones sold to use for bathroom heatlamps. They fit a standard electrical box and you can get them that allow times up to 8 hours or so. I think 2 hours is usually what I see recommended for ambient filters.

If you don't want to build something just buy the Honeywell 500250 air filter, they are about $130 each on Amazon. Three of them will move roughly as much air as the Jet, priced about the same and they are HEPA rated. This also allows you to have them in 3 different areas of the shop. Mo better.

BTW if you use the Honeywells the charcoal prefilter can be washed numerous times, the effectiveness of the charcoal/carbon is shot but in the shop it probably isn't an issue with smells (its going to smell like something anyway) but they still work fine as prefilters for years. If you are lax on cleaning you may want to rig a filter for the prefilter, easy enough to wrap the bottom of the Honeywell in more porous foam (like window unit filter foam).

[Jeff Aubrey]

Jeff

Could you post a picture of how you have you fans on the door?

I added a photo to this reply. It is upside down. Sorry I don't know how to fix it.

[Jim Becker]

Using a box fan like that for intermittent air flow works just fine. Folks should be careful, however, about running these long-term/constantly in a dusty environment. There are a lot of folks in the equestrian world who have done that for summer stall cooling because of cost and suffered tragedy when their barns burned down with loss of equine life. Our woodworking shops are easily as dusty as a barn can be, if not more sometimes, even with good DC. Consumer grade box fan motors are not particularly well suited to the conditions. For a little more investment, one can buy a very nice fan that's rated for the environment and they are even available designed for ceiling and wall mount.

[Michael Cummins]

I haven't done this yet, but have been thinking about it, wonder what people think.

I'm planning to build a downdraft table into an outfeed/assembly/multipurpose table that will likely live at the outfeed end of table saw most of the time. This will be connected to my 5hp 16" CV cyclone with 6" ducting. The sanders etc will be attached to my CT26. Thinking that double collection will work well for the handheld sanding operations...

Eventually looking to spend the coin for the iVac system for the major equipment. One feature of that system is the automated blast gates and timed overrun for the dust collector, plus one blast gate will always be open even if no equipment is running. I was thinking I'd set up the downdraft as the open gate when all others are closed, and extend the time the dust collector stays on a while, so that this downdraft table would be pulling air from near the middle of the shop (where a TS typically lives), at machine height where most of the dust is created. It would also keep the DC running for a little while between machine operations to avoid too much short cycling of the DC, all while cleaning the air a bit better (cyclone and HEPA filters). Not sure I'd want to leave my cyclone on for 2 hours after leaving the shop or anything like that, but might do a pretty good job of capturing the majority of airborne dust right after its created, and with much higher airflow/filtration than the typical ambient air filtration systems.

Might still do an ambient of some sort like the Pentz design, with a timer for air cleaning after leaving the shop, etc. But any thoughts on the downdraft/air cleaner concept?

[Jon Snider]

Using a box fan like that for intermittent air flow works just fine. Folks should be careful, however, about running these long-term/constantly in a dusty environment. There are a lot of folks in the equestrian world who have done that for summer stall cooling because of cost and suffered tragedy when their barns burned down with loss of equine life. Our woodworking shops are easily as dusty as a barn can be, if not more sometimes, even with good DC. Consumer grade box fan motors are not particularly well suited to the conditions. For a little more investment, one can buy a very nice fan that's rated for the environment and they are even available designed for ceiling and wall mount.

Jim and others,

could the same concern exist for an attic gable fan, put there mainly for cooling but inevitably in a dusty environment? Or maybe those have TEFC motors?

jon

[Jim Becker]

"Theoretically" the same concern could exist, Jon. A TEFC motor certainly would be desirable. Presumably, fans designed for attic/gable cooling are likely designed for continuous duty, too, unlike a common, cheap, consumer box fan. That said, I would hope that the dust concentration up that high wouldn't be anything like in the shop if one was collecting well at the source, etc.

[Art Mann]

One possible solution that I don't think has been mentioned yet is a powerful window fan in exhaust mode. I always use mine when the weather is suitable. It is an Air King model 9166F and it moves about 3500 cfm on high. That is far better than you can get with any filter system and you never have to clean it.

[Gary Ragatz]

Finally found some actual data on the woodworking specific machines:

https://www.finewoodworking.com/fwnpdfFREE/011213054.pdf

Is anyone concerned that these aren't HEPA rated? Seems like its just blowing the small stuff around.

Thanks for posting the article link. The particles they're measuring in the test are 0.1 to 10 microns. A HEPA rating is based on the ability to extract particles 0.3 microns and up, with something like 99.9% efficiency. And keep in mind that filtration isn't instantaneous - it's still going to take some time for the particles to get sucked into the filter.

So I thought that the fact that these systems returned the shop to the starting level of particulates in 13 minutes or less, after they stopped cutting wood, was pretty impressive. Even while the sawdust was being made, all but the Delta kept the concentration at less than half the level of the control conditions. Combined with collection at the source, it seems like these will help maintain a pretty clean shop.

[Chris Parks]

I have never been convinced about down draft tables because inevitably some of the available air flow get blocked by placing the object being sanded on the table and light fine micron dust floats and never gets pulled down by the draft. The least I would do is put a three sided enclosure around the table to trap some of the floaters. Getting really pedantic about the whole thing a clear three sided enclosure and a strip curtain front like you see in some door ways would contain most if not all of the sanding dust. Over kill? possibly but it would fix the problem for sanding small stuff. We built a dedicated sanding room for a chair manufacturer which was ventilated by a CV Max and it worked brilliantly but not everyone has the space or need to go to that extent. The incoming air was dragged from the floor up and there was very little that escaped the air flow.

[Jim Becker]

Chris, I think that the size of the downdraft table matters because a larger surface that's perforated will have enough air flow to capture dust that comes off the workpiece, despite said workpiece blocking part of the surface. Of course, that sets up the conundrum of having enough shop space to accommodate a larger down-draft table, but being creative can help...and auxiliary work surface could be placed on top for things like incidental assembly and "portable" tool usage when sanding isn't being done.

[Chris Parks]

My take on DD tables is if you can't feel a strong draft past your face onto the table then fine micron dust is floating away from the table and even then I would doubt that a DD table gets more than a large percentage of the fine dust. Call me a sceptic.

[Ed Gibbons]

I read several years ago it was not good to run these air filters when in the shop. They stir up the fine dust and that becomes the problem. On the way to the filter, the dust passes by the woodworker. The recommendation is to run the filter after leaving the shop. I use 2 box fans that I place on the window sills and vent the air directly to the outside after leaving the shop. I have a cyclone but I also use a dust mask.

[Tom Bender]

David (OP)
If you install it to pull air from the saw room and blow it into the other t=room it will keep the other room pressurized relative to the saw room.

BTW cheap furnace filters are not very helpful, good ones are better, HEPA are best.

[Ole Anderson]

A box fan is a poor choice as they are designed to move air with very little resistance, the kind of resistance you get by putting a filter in front of it. A cheap furnace filter will only catch large particles, so you need one with a high MERV rating, and those have a lot of resistance. I know. For several years I used a box fan with a Merv 8 or 9 filter with a cheap pre-filter in front. Even on high, the air flow was cut to almost nothing, especially after the filter started clogging. If you DIY, use a furnace blower which uses a squirrel cage fan which is designed to flow air with a filter in front of it. I ended up with a DustRite filter from Rocker (they no longer make it). Even with the filters far from clean, I still get a lot of airflow.

[Martin Wasner]

My take on DD tables is if you can't feel a strong draft past your face onto the table then fine micron dust is floating away from the table and even then I would doubt that a DD table gets more than a large percentage of the fine dust. Call me a sceptic.

You haven't used a proper downdraft table if it doesn't do that.

Ours is 4x6 and moves 3900 cfm. Not much escapes it.

[Rod Sheridan]

Having a small shop with little space, I simply run the cyclone for an extra 10 or 15 minutes.......Much more cost effective for me than buying a separate ambient air cleaner.......regards, Rod.