My downdraft sanding table/ shop air cleaner

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  • My downdraft sanding table/ shop air cleaner

    This was featured in an issue of workbench, and i have wanted to build it since i read the article. The fan came out of an old furnace that my wife's cousins had replaced, but i know could be found at any local heating and AC repair place.

    I have about 130 bux into it, the plywood was import 13 ply 3/4" birch, that wasnt too bad, not baltic birch by any stretch, but, i will be building all future shop carts out of it. $38 per sheet at my local lumberyard. The mat came from lowes ($20), the power cord is 12' of 12-2 with ground, bulk extension cord ($8 on clearance BTW) 4 bux for the male plug, 2 boxes of drywall screws, ($3), small bottle of titebond 2, ($3), the filters were of the 3 micron variety on clearance for 4 bux each, and a quart of satin poly for 6 bux.

    Now the pics:

    The heart of the beast!! the web frame holds the filters up, and the cleats just above that hold them down, and also hold the swiss cheese top up, you can count the holes if you want, but there is 384 1" holes in it, (which BTW takes 2 1/2 hours and 2 cups of iced tea to drill, lol) I pretty much crawled to the house after drilling all of them, i used a not so great spade that i had. GLAD I SAVED THE 5 DOLLARS ON A NEW 1" SPADE BIT!!!

    heres the filters installed, note the access panel that is not glued for future maintenence, good thinking on Workbenchs' part

    Here's the final product, she'll pull smoke from 18" above the top, not too shabby, if i decide thats not enough i can always rewire the fan to high (its on medium now). Also note the storage for all my sanding goodies, gets that stuff out of all of my other precious storage place and puts it near where i'll be using it

    What really gets me is how quiet it is, all you hear is the air moving, if anybody has considered a similar project i will highly reccomend this one, (I will also highly reccomend buying a new TOP O' THE LINE 1" spade bit)

    Thanks for looking,


    \"Run Varnish, Runnnnnn\"

  • #2
    That's really very cool. I'd love to have something like that in my shop, and it's something more important as we are now approaching winter.

    Keith Z. Leonard
    Go Steelers!


    • #3
      That looks great Kevin. I've been wanting to build one for some time now but haven't gotten to it so far.
      Monte (another darksider)
      Reporting Live from somewhere near Kalamazoo


      • #4
        Great results Kevin, I read that article very closely and put that on the list to do. Maybe I need to bump it up. I was curious how well it works. Did you insulate the blower chamber?

        Your making me kick myself. Twice since I've read that article (once last week) I saw furnaces on the street for trash pickup but was too tired to stop and take it home (newborns do that to you). It would've been worth it to at least see if the blower was working.

        Where did you get that 13 ply for $40 at? Borg has 5 ply for $40 and a 2x4 sheet of 13 ply is like $30.
        Be Kind Online


        • #5
          Nice! And a 1/4" piece of hardboard on top would make it a nice work/assembly/whatever table when you're not sanding. Sorry, that's my small shop mentality coming through.



          • #6
            I bought the plywood at a local lumberyard, it took a good many phone calls just to find some imported cabinet grade plywood, it does have a few holes, and the face plies are thin.

            I didnt insulate the cabinet, the furnace fans are just so dang quiet, plus its moving boatloads of air, according to the little table on the side of the blower, its between 2540 and 2650 CFM, and thats on medium, (depending on resistance of course),

            and it actually works better then i expected, like i said, if you're even considering it, go for it, you wont be dissapointed,

            \"Run Varnish, Runnnnnn\"


            • #7
              That's sweet. What issue of Workbench does the design in?
              "I'm growing older but not up." Jimmy Buffett


              • #8
                quote:Originally posted by Handy Al

                That's sweet. What issue of Workbench does the design in?
                its out in my shop, if i can remember tommorrow i'll let you know,

                i think it was june '05,

                \"Run Varnish, Runnnnnn\"


                • #9
                  Well, that's on my to-do list now. Looks great!
                  - Dennis

                  "If your mind goes blank, don't forget to turn off the sound." --Red Green
                  and yes, it's a potato.


                  • #10
                    I've been meaning to get to one of these. I've aquired a 3200rpm 1hp compressor motor & plan to run two fans with it. I hope I can keep the drive shaft straight a balance across two blowers. I was wondering if it would move enough air to act like a dust collector if I cover the top and add a gate to the case. I thought I'd baffle the interior and place the air filters in front of the blowers instead of on top.

                    Could it work? or am I wasting time?


                    • #11
                      problem with this fan design, is that it doesnt actually create any static pressure (AKA: suction)
                      you do need some SP for a dust collector to efficiently opperate,
                      and to actually move chips you need alot of air flow (something like 4000 Feet per minute velocity)

                      this guy has a ton of info and will also gladly tell you that the sanding table i just built doesnt work. It does work much better than
                      the one i had.
                      he does have health problems so dust collection has to be complete and total,

                      \"Run Varnish, Runnnnnn\"


                      • #12
                        Very cool. Build me one?

                        Seriously - How often do you think you will have to change the filters?


                        • #13
                          Yea...whats your filter life like, and can you just vacue / blow them off a couple of times before you need new ones?
                          Awww forget trying to fix it!!!! Lets just drink beer


                          • #14
                            at the rate they're going im anticipating an annual cleaning, and even then it would just be vacuuming them out, my sander catches quite a bit of the dust, this just gets the stubborn stuff.

                            Pretty low maintence in my mind, although i've found it circulates heat well too, as well as just filtering the air in the shop, so its on most of the time when im out there.

                            lots of surface area with the pleated filters, i would imagine that helps too,

                            \"Run Varnish, Runnnnnn\"