Lilly's Crazy Home Woodshop: Homemade Air filter

I came across an interesting article while looking for information on wood dust which said the average hobby woodworker breaths in so much more dust than a professional with dust control mechanisms. Wood dust is bad to breath (although, how bad is up for debate) and that makes me want to take dust control serious.

To start my dust control system for my basement wood shop, I first added a cyclone to my ShopVac. As a follow up, I started to build myself a homemade air filter for wood dust. There are lots of pictures on the internet from people who have made their own, so her comes one more set. Below are some final pictures of the dust filter in place.

To start with, I got scroll cage blower from my local AC shop. Thankfully my wife and I bought an AC from them so they were willing to help us. The fan came with several wires for the four different fan speeds. I built a 4-way selector switch to choose between the different fan speeds. In addition, I added a 60-minute bathroom timer, so I can let it run after I am done and it will turn itself off.

I think the air filter system got away from me in size, like most of my projects. Oh well, that is part of the fun and challenge. The first filter is something that is super course and was given to me by the maintenance guy at work, who needed a small piece, but the minimum order was about 100 times what he needed. The second filter is a 20” x 25” standard pleated filter that is 1” thick from the local hardware store ($4). Using their ratings, it’s not a very fine one. The third one is a 20” x 25” that is 4.5” thick and the highest rating that they have ($32). The final filter is one that I made and should be the finest.

This final filter is made from six filter socks that were headed to the trash from where I work. They are ~ 3” in diameter and about 12” long. I then put them on a plywood board with some 3” PVC pipes going through. The pipes are glued in place and then the socks are hose-clamped in place. One reason that the unit got so big is that I needed room to have the socks folly extended, which made the filter housing MUCH larger. Upon talking to the engineers at work who know much more about it than I do, I should have done a calculation to determine the ratio of sock area to air flow. Oh well, I hope I am not using such a high air flow that the very fine particulate gets sucked though the sock bags. Nothing I can do at this point.

The outer boards were all chip board. This made the unit heavy; however, it was free as the boards were headed to the trash after unpacking a crate at work. The frame was made of all 2x2’s. The part that held the filters is surrounded by brown Masonite board. Each filter is then sealed with some foam, like you use on an outside door. To help make it air-tight, as I want to make sure the air passes through the filters not cracks, all of the boards are glued and screwed down to the frame.

Below are some pictures of the work in progress and final part.

Enjoy,