Mobile Air Cleaner Cart

Often times it takes a bad situation for you to make some necessary corrective changes. This is definitely one of them. While I’ve had the intentions of making an air cleaner for my shop for a while now it wasn’t until I got yet another sinus infection that I decided to take greater measure in regards to cleaning the air in my shop. My body definitely doesn’t like walnut dust and has no problem letting me know. I already installed a HEPA upgrade kit for my dust collector and today I’m making a mobile ambient air cleaner cart to clean the shop while I work.

DIY air cleaners are not a new topic. People have been making them for quite some time. All it takes is a decent blower motor to move a lot of air and some good filters. It doesn’t make much sense to make an air cleaner if you’re going to use low rated filters that won’t get the small, dangerous particles.

To move the air I’m using is an old furnace blower motor that I picked up from Shawn Stone. After taking the motor out of the housing I found the wiring diagram, hooked it up for the slowest speed, and tested it in both free air and again with filtered restrictions. The amperage draw during theses tests was on par with the rating on the motor label so I was good to go for a fan source.

Filters can be expensive. My original intention was to go to my local home center and buy four of their best filters. The cost ended up being $85.56 with sales tax and the filters didn’t have a MERV filtration level listed on them so I passed on getting them there. I ended up getting a box of six MERV 13 filters off Amazon.com shipped overnight to my house for $35 less than the price where I live. So that’s the route I went.

woodshop air cleaner cart (1)

Next up was to decide where to put it in the shop. My original plan was to make this cart for my grinder but I accidentally found out that it fits below my drill press very well. The next best thing was to replace the least valued cart in my shop, which is the planer cart. It’s a great design that works very well but unfortunately I just pile crap on it more often than not.

woodshop air cleaner cart (2)

The design I came up with is very simple and relatively compact. The blower motor sits in the middle on the base of the cart. Four legs hold the plywood panels and four air filters. The top and bottom are just 1/2” plywood. Casters on bottom with the planer on top. Also, and integrated power switch. Very simple. If you would like the SketchUp file I created just click here.

sketchup air cart

The legs were sized in the design to be regular 2×4 boards. I thought I had some scrap 2x4s on hand but as it turned out I did not. However, I did have some extra 2×10 stock so I cut my material out of them. The first step for almost every project of mine is at my miter saw station. It’s so convenient to have a dedicated miter saw station that can handle large material with ease. It’s also got a ton of storage. I highly recommend making something similar if you can.

woodshop air cleaner cart (3)

After rough cutting to length the boards are ripped at the table saw. I didn’t show it in the video but I actually cleaned these up a little bit at my jointer as well.

woodshop air cleaner cart (4)

Each one of the legs needed to rabbets cut on opposite corners. The dimensions of the rabbets were not symmetrical so this required a different setup for each of the cuts. I chose to use a regular table saw blade to remove the material with two 90 degree passes. In this picture I’m making the final cut on one of the rabbets. Notice that the waste material is on the outside of the blade and not between the blade and the fence. Do not cut rabbets like this with the waste material being removed between the blade and the fence. It will almost always shoot back like a missile when it is cut free.

woodshop air cleaner cart (5)

The first trip to the miter saw was for rough cutting. With all of the leg joinery milled I setup a stop block to cut all of the legs at their final length.

woodshop air cleaner cart (6)

All of the plywood on this project is scrap 1/2” plywood. It’s birch PureBond hardwood plywood. I’ve been using this stuff for over a year now and have not had any problems out of it. And it’s made in the USA and formaldehyde free which are both great.

woodshop air cleaner cart (7)

All of the lower panels are the same size so cutting them is pretty quick.

woodshop air cleaner cart (8)

The blower motor didn’t have anything convenient on it to use to mount it to the cart so I added a couple of scrap pieces of pine. These are secured to the blower housing through the inside with sheet metal screws.

woodshop air cleaner cart (9)

With the mounting situation figured out I transferred the appropriate geometry for the exhaust opening on one of the panels. To cut it out I first drilled four holes on the interior corners and then connected them with a jigsaw. You can get surprisingly straight and smooth jigsaw cuts with a decent blade and a speed square. I’m using an inexpensive 12” plastic speed square here. It’s one of my favorite under-valued tools.

woodshop air cleaner cart (10)

A quick test fit determines I didn’t screw up with my measurements.

woodshop air cleaner cart (11)

For assembly I started with the front and back. To keep everything in place while I drove screws I used a pipe clamp with gentle pressure. I didn’t want the legs to bow up on the sides. Only enough pressure to prevent the panel from sliding as it is secured.

woodshop air cleaner cart (12)

Next, the front and back can be joined the same way with the remaining panels. Side note: Look at those beautiful flags :)

woodshop air cleaner cart (13)

With the frame completed the top and bottom panel dimensions are determined. Again, 1/2” plywood is all that is needed. The top and bottom are the same size.

woodshop air cleaner cart (14)

To secure the top and bottom panel I used one 2” screw per leg.

woodshop air cleaner cart (15)

Where the lower side panels and bottom panel meet I added a strip of really strong duct tape to prevent any air seepage through the joint. This joint is just a butt joint and might open up by a tiny amount over time and I didn’t want unfiltered air to be sucked in. Is there anything that good duct tape can’t fix?

woodshop air cleaner cart (16)

Finally the blower can be installed. I made sure to use appropriate size filters in the design that would allow enough room to pass the blower between the legs.

woodshop air cleaner cart (17)

Four screws were added along both the top and bottom of the exhaust opening to secure the blower to the cart. It’s also just sitting on the base of the cart. These screws prevent it from moving.

woodshop air cleaner cart (18)

The rabbets in the legs provide a surface for the filters to rest against and prevent collapsing in but at this stage there isn’t anything to prevent the top and bottom of the filter from collapsing. So I glued on some scrap plywood for the lower edge of the filter.

woodshop air cleaner cart (19)

And added some scrap pine along the top edge of the filter area.

woodshop air cleaner cart (20)

The electrical is extremely simple. I chose to run power in through a small hole on one of the side panels. A few zip ties on wire on the other side of the plywood prevent the wire from being accidentally pulled back through. From there the power is ran through another set of wires up to a switch mounted on the front of the cart. If the switch is activated power will then run back through the second wire and then power the motor. This is a very simple setup and much greater information can be found on it with a quick Google search.

woodshop air cleaner cart (21)

To make the cabinet mobile I salvaged the casters from the previous cart.

woodshop air cleaner cart (22)

The last step was to add a couple of swivel clips to hold the filters in place. These are just pieces of 5mm hardwood plywood (sold as underlayment plywood locally) secured with a single washer head screw.

woodshop air cleaner cart (23)

And the cart is complete. I really like not only how well this turned out but how easy it was to build.

woodshop air cleaner cart (24) woodshop air cleaner cart (25)

 


 

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18 Comments

  1. Vic

    Good job Jay. I’ve been wanting to do something like this for a long time now.
    Will you ever start painting / staining any of your stuff ? Carts, tables whatever ?
    Your shop is really awesome and you obviously have some favorite “teams” that have some great “colors.” Using one of your favorite team’s colors would make your shop really come “alive.”

    Just thinkin’

    Again, great job on the video.

  2. Jerry

    Great project, what we all need. Gave away by blower motor when I moved, need to find another one for this project, All your videos are informative and well made. Keep them coming. This is on my list of must have.
    Thanks
    Jerry

  3. Dan

    Like your 1/2 “SCRAP” birch plywood, I never have “scrap” plywood looking that good. Like the cart, I’m now looking for a furnace blower fan.

  4. Eric R

    1) Your sinuses are going to thank you.

    2) Nobody but nobody installs casters faster then you.

    3) Love the way you raught the cart to dance to your closing music.

    Nice build Jay.

    Thanks

    Eric
    central Florida

  5. James

    Hey that’s really nice I’m planning on building me one and my do it just like you did thanks for the great ideas

  6. George

    Jay — here’s my 2 cents’ worth — I like the mask you are now using. I like the HEPA filters you are (and will be) using. Why, you ask, am I even bothering with telling you this?
    Because, in researching emphysema (yes, I’m an ex-smoker, and I’ve got emphysema) I came across some info from a guy who was talking about the micron-sized dust we create when we do much more than just look at a piece of wood. Yes, invisible wood dust.
    So, I’m gonna close the barn door now. I don’t want to lose another horse!
    I know that I caused my problem, and I would not wish emphysema on even my worst enemy. (Well, maybe on my truly worst, worst-worst enemy! But not on anyone else.)
    I will just say this, and hope that anyone who reads it considers it carefully — it’s a real pain in the you-know-what to not be able to get ‘air’. I can no longer ski, SCUBA, garden, dance — can’t even make love right anymore — I could still do these things and a lot, lot more if only I could get air.
    Take care of yer lungs! It will definitely be worth the trouble and effort to put on that mask (every time) and use the best filtration system available.

  7. Sawdust and perfume

    Thank you for sharing this build. I have been putting off building an air cleaner for my shop but this has given me inspiration. It is now a MUST do, as soon as I locate a blower motor.

  8. Little Jack

    Nicely done…I’ve built some very similar carts…some suggestions to issues I came across would be…to mount the switch “flush” with the leg, like a wall installation, (less protrusions to snag as you work around it), and also add a duplex to plug in the planer or any other tool, and eliminate additional extension cords. Larger casters are a big plus… I get mine at Harbor Freight when their moving carts go on sale. For $7.99 you can get a cart with 3″ rubber casters. Toss the cart, salvage the casters…that’s 2 bucks a wheel!!

    Not trying to be critical…you did a great job!! Especially emphasizing “Is there life after scrap?” You bet!!

  9. joseph.laviolette@gmail.com

    I use a set up with the same basic design, It’s awesome and works really well. However I found I was going through pleated filters at an alarmingly fast rate. I found using a super cheap nested fiberglass filter in front of my MERV-14 pleated filters more than quadrupled their lifespan with no noticeable decrease in airflow. It traps all the rough stuff so the pleated filters only get the fines. I didn’t make provisions for mounting the extra filters, I just bungee corded them around, but a more elegant solution would be easy

  10. roachdr

    I noticed that you have progressed in the film making business so much since I started watching your videos. I applaud you, sir. Oh, and you make some really helpful and useful shop organizing stuff. Bravo! I try to upcycle wood from pallets and keep my wood costs to a minimum. Use the scrap wood to build more stuff! I need to start doing the face mask filters like George said above, too.

  11. Bob

    Well done! Anyone have an idea for a modification that would prevent the exhaust from kicking up dust from the floor?

  12. Joel

    Hey Jay,

    Really great video. Good idea, better execution and great videography!

    Thanks for taking the time and for sharing.

  13. Bob Emery

    Another great build! I built a similar type of dust collector several years ago. This unit had 3 filters of varying sizes, having the coarsest on the outside and finer ones behind. This unit only had the one inlet. The dust collector worked good, too good. I spent lots of time cleaning and replacing filters, that said, they performed their intended job. I didn’t have any other dust collection in my shop so I built a Cyclonic dust collector with a 1 HP motor, then replaced with a 2 HP. Many revisions along the way.

    Long story, but my retirement present was a Oneida V3000. All ductwork was replaced with 24 awg, with a 7″ header. I had to install screens on my router table, table saw and compound miter saw, as these tools are piped in permanently and the draw from the fan is out of this world. Awesome machine and with Oneida plans and my local tin shop, this install is right out of a text book.

    Now I am tackling the smaller tools for dust pickup. Getting back to your unit, I may build one to add to my dust collection arsenal.

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