Does anybody have a set of plans for a downdraft sanding table using an old furnace blower?

I have seen numerous 'threads' and discussions on the subject, but no PLANS other than a few pictures.

orksecurity6 years ago
Plans have appeared in various woodworking magazines, and are generally available for a few bucks from them and/or from woodworking catalogs. You can also find plans/parts for small ones that will hook up to a shop vacuum. It isn't all that complicated: Perforated work surface (ideally with number/size/spacing of perforations matched against the amount of suction that fan can produce), an airtight "wind box" underneath to distribute the suction evenly across that surface, a fan to produce the suction, and filters before and/or after the fan to keep the dust from just being sprayed back into the air.

If you're going to use a fan that isn't specifically designed to be able to tolerate dusty environments, I would STRONGLY recommend having filters between the dust and the fan. Fine sawdust suspended in air can be a highly flammable (in extreme cases, explosive) mixture; you don't want to mix it with possible sparks.
Presumably you need to make two halves of a shallow box. I'd use 3/4 MDF and hollow a series of very substantial channels with a rounding bit. Then I'd use something like a 3/8 forstner to form holes every inch or so.

Then I'd seal the channels with a coating of PVA and then screw another piece on the back. Your 1 1/2" thick sandwich should be thick enough you can fit a pipe off the back, and sit it on your (FILTERED !!) blower.

frollard6 years ago
What's to learn? Fan sucks air through a table with holes in it -- build a box below the table to hold the pressure, and consider a cyclonic dust filter then a mechanical filter before the fan...