Pictured above is my Shop Built Air Filtration System. (Click on it to enlarge). You are looking at the exhaust end. It is a very simple construction -- basically, just a box. The top, sides, and bottom are 1/2" plywood I had sitting around the shop. Everything is screwed together -- no nails or glue, just in case I need to take it apart sometime. The size was dictated by the shape and size of the blower.
I used a 1500 CFM fan blower unit rescued from a HVAC place near my house. The price? $20. You'll also notice the small timer switch on the right. This is a 1 hour timer with automatic shutoff. Whenever I'm done in the shop I give it a half hour twist to finish filtering all the dust hanging in the air. If I were to do this over again, I'd get the 4 hour timer instead. I keep having to turn this back on every hour, and it always manages to turn off when I've got my hearing protection on and some piece of power equipment, so I might not notice that it is off for several mintues..
Just another view of the box. This from the intake, left side.
(Click on any of the pictures to enlarge).
The above pictures show filter placement. (The metal bar is not part of the air filter unit). The filters sit in a little slot I made for them. The blue one is in front, the 3M filtrete filter behind it. The 3M filter is supposed to give sub micron performance. I've had it for about a year and cleaned it 3-4 times. Its about at the end of it's useful life. I'll replace it with a washable electrostatic filter here shortly.
Here is a view of the inside of the box. There isn't much to this. I
think the entire project took about 4 hours to build.
Total cost of this project was about $65. Breakdown: $20 for the fan/blower, $25 for the timer. $15 for the 3M filter, and $5 for the washable filter. Plywood, screws, and cord don't count as they were sunk costs.
When I remember to use this filter system regularly, it does a good job of keeping the layer of dust off my tools. Now, I find that it is the quick 15 minute projects where I don't turn it on that generates the most dust.
Hope you enjoyed this!