MIMF

I am going to be using a different work space for a while which wi going to need more serious attention to air quality than in the past so I am consider an air-filter unit. The Jet AFS 400 or 1000 are likely candidates. It needs to be moderately mobile as I want to take it to a different workshop temporarily late in the summer.

Any thoughts you can share about these units or similar?

Simon,
If you will be running a de-humidifier you can simply attach a thick media pad to the intake of that unit, it will be quieter than a metal box with a noisy blower. For filter media I use 2" thick (5cm) polyester spray booth intake air filter that has a sticky "tackified" fine filter on the inboard side. This stuff comes in big rolls or pads and it works exceptionally well as the sticky pad keeps fine dust from falling off when you bump into it. I just vacuum off the coarse outside as it gets filled up.
If you don't need a dehumidifier you could just run a window box fan on low speed with the same filter media across the front.
Here's a link to the type of media I'm talking about: https://www.sprayboothfiltersandsupply. ... 5-2090.htm
I also use it over the intakes for my forced air furnace too.

I bought an air filter from Grizzly a couple of years ago when they had them on sale for $100. It is very quite but moves a lot of air. The two stage filtration appears to be very capable of removing particulates. It has a remote control and a timer to turn the unit off after a set time which is helpful because the unit is so quite I forget its on.

I've had the AFS1000 for about 15 yrs and have been happy with it. The controller died about a year ago but was fixed by replacing a failed capacitor. I have it hung from the ceiling so it's out of the way, but that makes it a bit of a pain to get to for cleaning/changing the filters.

I decided to try something cheap for this. I got a fancy furnace filter and taped it to a box fan. I hang it up near the ceiling and it does an amazing job of keeping the air in the shop clean. I'm not sure the expensive machines do much better.
Simple and cheap and the filters are readily available.

-Eric

I don't have any experience with a commercial air filtration unit. But, I made the one pictured with a furnace blower fan. It moves about 1500 cfm. The filter is one of those 99% small particle furnace filters from Lowes. I vacuum the filter when it gets ugly and replace it when the air flow decreases. Also pictured is a particle counter. It gives an instantaneous count of particles .5 micron and 2.5 micron in .1 cu ft of air. The grandchildren playing on the rug in the living produced a 700 count of .5 micron particles, so I arbitrarily decided that I would turn on the filter box when the count exceeded 300. Running the drum sander with the dust collector on doesn't raise the count, but any other power tool does. The dust collector doesn't get all of the dust from the bandsaws or the other sanders. I have had .5 micron counts as high as 12000 when using the random orbital sander (over a downdraft box) and above 30000 when I've been spraying waterbase lacquer (using the fan box with the spray filter shown beside it pulling from a box I spray into and exhausting outside). The fan box can clear the air from a count of 5000 in about 10 minutes. A 30000 count takes 30 minutes (I remove it from the spray box and put in the fine furnace filter). While the box/filter combination has reduced the .5 micron count below 10 occasionally, I'm usually satisfied to get it below 100. Any activity in the shop will raise the count.

I purchased the Grizzly unit (probably around the same time as Barry). I have not done any particle filter testing but it sure seams like it is doing a good job. It is pretty darned quiet all things considered; it is basically white noise. I don't notice it at all when I have music on. I pretty much turn it on full speed and set the timer for maximum duration when I go in the shop and don't think about it again until the next time I'm in there.

I have an older Jet that was billed as a "benchtop" unit. Plenty big enough for my little 500 sqft shop. Hung from the ceiling, it makes a HUGE difference in the air quality.

I already have full dust collection on all the large equipment (TS, BS, Jointer/Planer Router table) and a Festool shop-vac permanently attached to the smaller tools (oscillating sander, drill press, sliding miter and mortiser), but hand-sanding, hand planing and cutting any kind of MDF inevitably puts some stuff in the air. The Jet unit I have handles it just fine. I added a timer to it (plenty of room inside, so a little drilling and a couple of connections was all that it took). My measure of how well it works is how long it takes dust to appear on dark surfaces, like the flange on the black cyclone unit or the handles of my hand planes.

Before I started using this, I noticed that I'd develop a bit of a dry cough after working in the shop for a couple of hours. This eliminated that.

Thanks guys.

Charlie Schultz wrote:…. a bit of a pain to get to for cleaning/changing the filters.

How often do you need to clean/change filters? I assume cleaning just means using a vacuum cleaner on it.

Steve Sawyer wrote:I have an older Jet ….. Hung from the ceiling, it makes a HUGE difference in the air quality.

I can see fixed pipes going behind the unit in the picture. I assume these having nothing to do with the Jet unit and are attached to some other pipe that is not visible going to your main dust collection.


We don't have grizzly in Europe but I had a look at their site anyway. I guess some of the stuff is standard chinese with their name on it so I will keep an eye out for no-name brands.

How often do I change/clean the filters? Not often enough <g>. It depends on what I'm doing in the shop. I tied a length of fabric to the exhaust grate (sort of like a kite tail) and when it starts to droop, I clean it out. There is a paper filter in front that can be cleaned/changed and a fabric filter in back of that that I pull out and vacuum clean.

My experience is that the hanging filter units do a good job of keeping your shop air visibly clean but having their fan circulating the shop's air keeps the very fine (invisible and dangerous) dust suspended in the air longer than having no fan. They give a false sense of security from a breathing safety standpoint and no way of knowing when the air is clean. Even if you do get the air clean by running for a few hours after leaving the shop, just walking through the shop the next morning re-animates the dust which settled before getting trapped in the air cleaner filter. If you haven't drank from the firehose of information on dust collection that Bill Pentz has compiled here's a link: http://billpentz.com/woodworking/cyclon ... corner.cfm The best practice is to capture the dust at the source and not allow it to get into the shop's air.

I use a 20" box fan with a 20x20" Filtrete type hvac pleated filter duct taped to it blowing "clean" air on my varnish work to keep the rocks, sticks and small furry animals off while it dries. I use it in a dust hood format (ie: pulling air through a large open ended cardboard box) and hand sand/scrape inside the box. I also use a HEPA pleated filter on my vac for handheld power tools/general cleanup and each large machine is connected to a central cyclone with 6" piping which is exhausted through a large Wynn HEPA filter array.

Simon Magennis wrote:I can see fixed pipes going behind the unit in the picture. I assume these having nothing to do with the Jet unit and are attached to some other pipe that is not visible going to your main dust collection.

Yeah, those are the 6" ducts for the cyclone dust collection. That drop is about 2" from the inlet, and really doesn't impede the air flow much at all. See the pic below.

Also, you can see that I replaced the outer filter with a washable element. A bit pricey at about $50, but more durable and cheaper than the replaceable filters that you get from Jet or any other source.

Mark - you're right about collection at the source, and also about the exhaust "stirring up" the dust, which is why I have the unit canted just slightly to direct the air flow toward the ceiling to somewhat minimize this effect. You CAN gauge the air quality, but you have to spend some $$ to do so. I've been tempted as I'd like to really know how clean I'm keeping the air, and to alert me to conditions that compromise the air quality.

If you can't afford to stop dust at the source then you can still afford to stop it at the nose and mouth.

David King wrote:If you can't afford to stop dust at the source then you can still afford to stop it at the nose and mouth.

Yes... but the fine dust settles on surfaces and stirs up when you move air in the shop doing things which you would not normally be wearing a mask. It also follows you home on your clothes exposing others. When making fine dust definitely wear an appropriate mask but do the work directly at the intake of a box fan(~$15) or other high flow fan vented out an open door/window with make up air coming in from across the shop. This allows the dust to get out. When finished, close up and go back to unmasked work. If I were to have to use a temporary shop this is the least expensive, least invasive and most effective option for having safe and clean air when making fine dust that I know about.

The really fine stuff does not settle for a long time. An air filtration with a two stage filter has a much better chance of removing the sub micron level particles than a box fan with a simple house filter, or even the Filtrete or similar fabric filters.

Barry Daniels wrote:The really fine stuff does not settle for a long time. An air filtration with a two stage filter has a much better chance of removing the sub micron level particles than a box fan with a simple house filter, or even the Filtrete or similar fabric filters.

The filter I use will remove particles down to 5 microns once it's loaded up a bit. Modern 5" thick filters aren't like the furnace filters of old. We have a Spaceguard full-house filter on our furnace and it removes pollen and dander to non-allergic levels. Since I can't afford anything else, this will have to do.

-Eric

The thicker the filter, the better. That 5" should be effective.

HEPA filters are rated to remove 99.97% of particles that have a size down to 0.3 µm. And it's the sub micron stuff that cause the most problems because they get further down into your lungs.

Barry Daniels wrote:The thicker the filter, the better. That 5" should be effective.

HEPA filters are rated to remove 99.97% of particles that have a size down to 0.3 µm. And it's the sub micron stuff that cause the most problems because they get further down into your lungs.

Good point, Barry. That's another reason why I'm doing more with hand tools over time. I'm also using a P100 mask when I do really dusty things and I'll be looking for better ways to have cleaner air as I do more in the shop.

-Eric

That little particle counter in my picture above cost me a little more than $200 if I remember correctly. It measures half micron particles in the air. For me, it was worth it. It showed me that my dust collector with a nominal 1 micron filter works very well. It also showed that best 3M furnace filters that Lowes sells also work very well. I generally shun MBA speak, but if you want to change something, it helps to be able to measure it.

I have made the assumption here that measurements of .5 micron particles will correlate with the quantities of other particles near that in size.

Bob Gramann wrote:That little particle counter in my picture above cost me a little more than $200 if I remember correctly. It measures half micron particles in the air. For me, it was worth it. It showed me that my dust collector with a nominal 1 micron filter works very well. It also showed that best 3M furnace filters that Lowes sells also work very well. I generally shun MBA speak, but if you want to change something, it helps to be able to measure it.

I have made the assumption here that measurements of .5 micron particles will correlate with the quantities of other particles near that in size.

May I ask what particle counter brand/model you have and where you got it? That almost seems like an essential tool for serious woodworkers. I can measure the temperature, the humidity, angles, straightness, flatness, and so many other things. Measureing something that is dangerous seems important.

Thanks,

-Eric