I just buy MERV 12 furnace filters and put them on the air intake.
MERV 12 is good to about 1 micron.
You can go up from there to a MERV 16 which captures down to .3 microns dust.
I caution you to use staged filters because the higher the MERV rating, the more they cost. The MERV 12’s that I use are $13/ea and I change them every two months. It takes 4 of them to do a complete change.
The staged part gets changed every week in the shop and is a MERV 2 or whatever is cheap. I pay about $4 for three pleated MERV 2 filters.
I may make an intermediate filter holder to take a MERV 6, but for the moment this is keeping the dust out of the house and keeps the wife from frowning too much.
-- Improvise.... Adapt...... Overcome!
