Cheap shop air filtration
I've seen lots of people putting furnace filters on box fans, and from what I've seen it works ok. Problem I have with that approach is that the filters get expensive.
But I had a thought recently - I can buy a 3 micron dust collector bag for $25. I have been using the same bag on my dust collector for like 3 years - I just knock the dust out of it and keep on using it.
Why can't I just buy a dust collector bag, cut it down too get a panel that fits my box fan, and just keep knocking/vacuuming out the dust and reusing that piece of felt? This will work right?
If not, why not?