The Stumpy Nubs Workshop #56: Make your ambient air cleaner (Jet, Delta, etc.) a lot better!

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Blog entry by StumpyNubs posted 07-03-2015 09:59 PM 8282 reads 1 time favorited 21 comments Add to Favorites Watch
« Part 55: What makes a good cyclone? (Let's make one from wood...) Part 56 of The Stumpy Nubs Workshop series Part 57: Roy Underhill and Stumpy Nubs: Live in Kansas City! »

If you own, plan to buy, or even make an overhead ambient air cleaner, you have to see this… I’m tired of buying expensive replacement filters, so I mounted a Wynn cartridge to my Jet air cleaner! It made the system WAY more efficient (lots more airflow), improved my air quality (the Wynn filter is MERV15), and I’ll never have to change it (the filter is infinitely cleanable). I made this video as part of our NEW DUST COLLECTION SECTION of our website to show you how to do it yourself!

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21 comments so far

View DIYaholic's profile


19919 posts in 3454 days

#1 posted 07-03-2015 10:23 PM

Well done, sir….
Thanks for trying to keep my lungs functioning!!!

Where’s Mustache?
Did you lock him in the closet again???

-- Randy-- I may not be good...but I am slow! If good things come to those who wait.... Why is procrastination a bad thing?

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7812 posts in 3579 days

#2 posted 07-03-2015 10:29 PM

Mustache Mike was in the video, he was the one with the mustache…

My dust collection duct work is all being replaced so it’s not hooked up, so I put a lot of dust in the air. I’ve been cutting a bunch of MDF and I can’t tell you how glad I am I made this modification!

-- Subscribe to "Stumpy Nubs Woodworking Journal"- One of the crafts' most unique publications:

View Mean_Dean's profile


7043 posts in 3926 days

#3 posted 07-04-2015 01:32 AM

This is a great idea—I’m definitely going to follow along with the videos!

By the way, I also didn’t see Mike—neither hide nor ‘stache of him….....

-- Dean -- "Don't give up the ship -- fight her 'till she sinks!" Capt James Lawrence USN

View playingwithmywood's profile


444 posts in 2376 days

#4 posted 07-04-2015 03:25 AM

that’s right when you buy Wynn “its a Win Wynn situation”

I happily gave them my money and have been happy ever since great product and great people

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7812 posts in 3579 days

#5 posted 07-04-2015 12:14 PM

Mike was the one handling the stuff in the build footage.

-- Subscribe to "Stumpy Nubs Woodworking Journal"- One of the crafts' most unique publications:

View Roger's profile


21030 posts in 3583 days

#6 posted 07-04-2015 01:01 PM

Gr8 info and how-to Stumps. You da man.

-- Roger from KY. Work/Play/Travel Safe. Keep your dust collector fed. [email protected]

View DavidTF's profile


8 posts in 1922 days

#7 posted 07-04-2015 01:05 PM

Interesting, I was playing with this idea last night. I am a weekend woodworker and my shop is one “car” of a three car garage. The garage has a ton of hiding places for dust:( At the end of day I work in the shop, I use a leaf blower to try to corral the dust. Then I vacuum up the big stuff with a shop vac and set the timer on the filtration system and let it run for a few hours. After a day working with the router everything is covered with dust and the filtration system gets a serious workout.

Any thoughts how how to measure improvement with your modifications vs stock filters?

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7812 posts in 3579 days

#8 posted 07-04-2015 01:27 PM

There are three benefits- more airflow, finer filtration, and greater filter lifespan.

Airflow can be tested with various meters, but the easiest way is to buy a little pinwheel toy and hold it up to the intake. Compare the speed it moves with the stock filter to the new filter. The stock filter gives you about eight or ten square feet of surface area for the air to pass through. The Wynn filter is 300 square feet. Air doesn’t compress at the pressure the fan produces, so a larger “door” will allow a lot more air to pass through. Now, perhaps your system’s fan only moves so much air, so the original filter provides adequate space. But after a very short time that filter will take on dust and the space left for air immediately reduces. The Wynn filter has so much extra space that you can run it for months without any cleaning and it will still be able to handle 100% of your system’s peak airflow.

To test the filtration you would need an air quality meter. But you can also just compare the two. The Wynn filter is rated at MERV15, which is the level hospitals use to remove bacteria from the air. (We’re talking about the common areas- rooms and hallways. Operating rooms use a different standard.) The AFS stock filters aren’t even close to that. Do you need MERV15? Maybe it’s overkill, but if you can get it while increasing the system’s efficiency and saving money, why not?

The filter’s lifespan is easy to test. Some people have said they can clean their AFS stock filters a couple of times, and that’s it. To do it they have to take it outside and blow it out with air, which means breathing a lot of that dust in as you do (unless you wear a good mask). The Wynn filter can be cleaned as many times as you wish, right in place by blowing air on the outside of the filter. That dislodges the dust inside. You can then dump any accumulated dust out. But since you have so much surface area, you really don’t have to clean it very often. (I do it once a year and even that is plenty). And it will last for many, many cleanings- really the lifetime of your AFS. That means a one time expense for the filter upgrade, which will be a lot less than all fo the stock filter replacements.

-- Subscribe to "Stumpy Nubs Woodworking Journal"- One of the crafts' most unique publications:

View DavidTF's profile


8 posts in 1922 days

#9 posted 07-04-2015 02:11 PM


As a weekend woodworker, I find that I can get by with rinsing the pre-filter every couple of days and washing the inner filter every couple of weeks. It is not that bad, but it is still a pain in the keister.

I bought a 35A274NANO a couple of months ago to upgrade my HF chip/dust collection system. I’ll borrow that to run some tests.

Off to the home center to build one of the dual prefilter setup:)

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7812 posts in 3579 days

#10 posted 07-04-2015 03:36 PM

Dave- Washing is a no-no! They coat those filters to achieve the stated filtration level. Washing removes the coating. At least that’s the case with a lot of them. Maybe yours is different.

Save your money- You don’t have to buy another Wynn filter if you already have one on your dust collector, You can mount your AFS near your dust collector and run a duct from it to your big filter. You will have to either make some soft of big flange between the filter and your dust collector, or I would just cut a hole in the top of the filter, attach a starter collar like in the video and hook it up that way. If you change your mind later, just glue a piece of metal or plastic on the top of the filter to cover the hole.

-- Subscribe to "Stumpy Nubs Woodworking Journal"- One of the crafts' most unique publications:

View Desert_Woodworker's profile


2806 posts in 1993 days

#11 posted 07-04-2015 04:54 PM

The above Stumpy advice 5 stars! Now to “Where’s Mike?” I spotted him OK but what I noticed- a “tattoo” partially exposed on his right arm. Does this hidden symbolism hold a clue in the Stumpy episodes to come?
Question 2: Will you use the “Lincoln statue with the snow cap” in future episodes.

-- Desert_Woodworker

View DavidTF's profile


8 posts in 1922 days

#12 posted 07-04-2015 07:34 PM

OK, had some fun today:) I assume that is what this is really about.

I guess my initial question about measuring improvement was asking about how to cheaply measure total airflow in CFM through the system with different filters based on the assumption that both of the new filters would result in smaller pressure drops. I was hoping that you had a clever idea for a really cheap wind speed gauge:)

My filters are identified as washable. The instructions say to gently run water against the direction of air flow. This seems to work just fine for the prefilter. However, I agree that the internal filter seems to be losing it’s effectiveness based on the total unscientific method of running my finger across the workbench and examining the remaining dust. Lately, there does seem to be a film of very fine dust left in the morning.

Ok, now for the fun stuff. :) The prefilter worked awesome. For my first prototype I used two filters 24X24X2 inches configured in a V shape. (They are merv 8, have a low pressure drop, and were really cheap.) A couple of pieces of hardboard and some drywall corner pieces work pretty well.

I temporarily rigged up my existing filter with a couple of pieces of particle-board spacers and some weather stripping. It made a world of difference. Again very unscientifically, the pitch of hum on low speed with the new filter is about the same as the pitch of the hum with the old filters on high speed. I assume there some correlation between the pitch of unit, rotational speed of the blower, and volume of air flow.

Now the open question :) When I initially setup the unit. I experimented with the location of the afs to maximize air movement around the room. With the unit 5 inches down from the ceiling and 4 inches away from the middle of the longest wall, there was a slight but noticeable circular air flow pattern around the room. The new filters seem to diffuse the airflow more and reduce the circular flows. My concern is that the area around the new afs is really clean while the rest of the room is left unfiltered:( Maybe a future iteration could have some sort of “sleeve” over the output filter to restore the directional air movement.

By the way, thanks for the videos. I have watched many of them over the past couple of months.

Better get back to painting the trim or i’ll be sleeping in the garage again… at least the air quality is good:)

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7812 posts in 3579 days

#13 posted 07-04-2015 08:07 PM

David- The “pinwheel” WAS my cheap measuring tool. It isn’t very scientific, but the faster it spins, the more the air is moving. Try it without the post filter, then with it, then with a Wynn filter.

Merv8 is pretty fine, maybe too fine for a pre filter. You really want to just catch big stuff like hair and 2X4’s that may fly through the air. Your pre filters only have a couple feet of surface area, so they can’t let in nearly as much air as the post filter- which may be finer, but has a lot more surface area. I strongly suggest you buy the cheapest piece of crap filters you can get- like those blue ones the sell for a buck that don’t even have a MERV rating at all.

-- Subscribe to "Stumpy Nubs Woodworking Journal"- One of the crafts' most unique publications:

View DavidTF's profile


8 posts in 1922 days

#14 posted 07-04-2015 09:51 PM

I’ve got to go with the ducted version. I jury rigged a straight adapter to have the canister filter come directly out of the side of the afs unit. It worked like a charm. However reaching up overhead to detach the dirty canister for cleaning was painfully ugly.

FWIW, I have been taking a gallon ice cream bucket and scoping it full of dust from the dust collector and dumping it onto the tablesaw. Then I use the leaf blower to create a cloud of dust :) After 30 minutes I come back and check how much dust has settled on various places in the garage vs how much is in the filter.

View DanRos's profile


7 posts in 3133 days

#15 posted 07-21-2015 12:13 PM

The filters that sit on front of window air conditioners are pretty porous, if they are rated they are merv 1. I am going to pick one up at home depot today and try the pinwheel test. I would run with no prefilter and just go into the Wynn cartridge if birds did not ocasionally sneak into my shop.

I don’t know how many CFM my unit is, it is a 1/4 HP squirrel cage fan in a box. The Jet 1000 is 1/5 HP, so I hope mine is a little higher.

I just have to make a plug for the bottom of my Wynn and then start sucking.

Hey, stop standing on your head while you look at this image of my AFS on top of my upper cabinets.

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