Air cleaner/grinder station

Real interseted to see how this specs out. I’ve got an old furnace blower I use as a portable to pull drywall dust out of rehabs, etc. Would really appreciate it if you could let me know how the filter sizes work in relation to the blower size and cubic footage of the shop. Thanks for the ideas.
Looks like a real handy place for a couple of extra plugins as well.
BTKS

-- "Man's ingenuity has outrun his intelligence" (Joseph Wood Krutch)

I am not sure how to answer that question. I’ll explain why the filters are the size they are. I needed room to work inside the box, that’s why the 20×25 outside filter. I needed to be able to get the motor inside the box, after the box was built. I have the same size fan unit in the garage. It is 20’ x 28’ , outside dimensions, with 9’ ceilings. It does a good job in there, it’s only filter is a 16”x20”. I don’t remember seeing any spec’s on the motor, but I’ll check. The basement is 24’ x 24’. I haven’t ran this long enough to have to change filters yet. I’m hoping the cheap outside filter will save me from buying expensive inside filters.I have the fan outlet blowing away from the grinder side, and I do notice a nice breeze in the basement.I hope that helps.There is a 2 gang outlet on the side, along with a switch to turn on the blower.

-- It must be jelly baby, cause jam don't shake like that...

Very nice!!!!!!!

-- Only the Shadow knows....................

Hairy, thanks for the follow-up. Don’t worry about technical specs, I was asking a general question and you covered it perfectly. If you have a nice breeze then I assume there is plenty of filter square footage to allow frequent air exchanges. I believe I will try something very similar, when the to-do list shrinks down to one or two pages.
Thanks again for the input
BTKS

-- "Man's ingenuity has outrun his intelligence" (Joseph Wood Krutch)

Hairy: This looks like a great unit. Nice job and it’s a table to boot.

-- I've been blessed with a father who liked to tinker in wood, and a wife who lets me tinker in wood. Southern Delaware karson_morrison@bigfoot.com †

For about a month now I’ve been working on makeing a similar air filtration unit with a 4 speed furnace blower. I should be done with it in a couple weeks. I allready have a dust collector and a Delta air filtration unit, but I had a blower laying around that I allways wanted to do this with it, winter seemed like a good time to do it.

When I built the one in my garage, I used 3 seperate light switches to control the 3 speed motor. I was too cheap to buy a 3 speed switch.On the workbench, without a filter, I could definitiely tell the different speeds.With the filter, I can’t tell the difference.Of course, I didn’t know this until it was hanging and I stood back to admire my work.It’s something to think about.

-- It must be jelly baby, cause jam don't shake like that...

I just put the power on one switch, if I want a different speed I’ll have to simply move the power wire to a different terminal. I doubt I’ll be changeing the speed much once I find out which speed works best. Air restriction shouldn’t be much of a problem, a single 16” X 20” X 1” pleated filter goes on two sides of the box. I used angle iron for the frame to keep the size of the unit down.

Hairy, I guess I forgot to add that you did a good job makeing it as a dual purpose unit. Mine is more the size and hieght of a end table in a living room. I’ve also seen people make downdraft tables with furnace blowers. fairly inexpensive prodjects, but you know how it is, they take time to do, usually more than expected.