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  • Downdraft sanding table help suggestions needed

    I have most of my dust collection under control with a 2hp cyclone system and now I want to add a downdraft table because that is where I am now getting most of my dust. I might even start to like sanding if I can get control of the dust. I had thought to use a furnace fan in a table to pull the air and through a set of filters in a 24 by 36 inch top surface. I have a choice of a single speed belt drive furnace fan or I can use a 3 speed direct drive furnace fan. The 3 speed unit would take up less space in the cabinet being direct drive and I suppose the slow speed would probably move enough air to operate a downdraft table. I am at the design stage (on paper) and thought why can I not just hook up a downdraft table to the cyclone? I could easily attach it to 2 four inch suction hoses and if I needed I could buy a length of flexible 6 inch. If I recall the cyclone pulls 1345cfm and it is possible that a single 4 inch connection would do the job. Using the cyclone would probably be noisier but I am not sure that should be my first consideration.

    So I ask you which way would you go and if you have pictures or designs that are working I would appreciate any suggestions and help.


    Jake
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  • #2

    Re: Downdraft sanding table help suggestions needed

    Re: Downdraft sanding table help suggestions needed

    1st keep in mind that I'm not the most knowledgeable one here, but I thought I could throw in my 2cents.

    I think that using the cyclone would work just fine, I don't have one but I don't see why it would not work. However like you say it would be noisy. Not sure but there could also be a mobility issue.

    I made a Downdraft table last year here's a link to the thread.
    http://forum.canadianwoodworking.com...ighlight=8-729

    I used a 2 speed belt driven furnace fan, (you can get them for cheap from a plumber). On the slow speed you can not hear it. I always leave it on slow when I'm in the shop and it makes a big difference.

    Anyway I just thought I would point you to my design for a look. There are lots of others out there as well.
    bob
    http://gloakproductions.ca/

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    • #3

      Re: Downdraft sanding table help suggestions needed

      Re: Downdraft sanding table help suggestions needed

      Hi Jake,

      I decided to make my new hand tool work bench a sanding table also...

      Basically it's a 2" x 2" frame with a pegboard box that's 44" long, 16" wide and 12" high. I enlarged the holes of the pegboard to 3/8" on the top and two rows on the top of the sides. It will hold a piece of sandpaper to the side when the dust collector is running

      Click image for larger version

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      Hope this helps,

      Cheers, Don
      Don Kondra - Furniture Designer/Maker
      Product Photography
      My Acreage Bird Photographs

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      • #4

        Re: Downdraft sanding table help suggestions needed

        Re: Downdraft sanding table help suggestions needed

        Jake, there have been quite a few discussions over the last few years on this subject so you can search them out. I made one several years ago that uses my DC for suction and filtering and it works pretty well. See response #4 in this thread http://forum.canadianwoodworking.com...ht=draft+table for the particulars. I think with your cyclone, you would have lots of air processed and cleaned. The filter on your cyclone may also be superior to the furnace filter route in some of the design.

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        • #5

          Re: Downdraft sanding table help suggestions needed

          Re: Downdraft sanding table help suggestions needed

          Don,
          Is that only a 4" hose !?
          Grillzy

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          • #6

            Re: Downdraft sanding table help suggestions needed

            Re: Downdraft sanding table help suggestions needed

            I have a little benchtop 24"x30" peg board top with a 4" line to a cyclone and it works great. It gets everything spec of dust.
            Paul

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            • #7

              Re: Downdraft sanding table help suggestions needed

              Re: Downdraft sanding table help suggestions needed

              Originally posted by Grillzy View Post
              Don,
              Is that only a 4" hose !?
              Grillzy
              Uh, yup...

              In the dead of winter, if I get the urge to blow the dust off my ceiling lights, etc. the air is "clean" within 5 minutes... and no messing with furnace filters

              Cheers, Don
              Don Kondra - Furniture Designer/Maker
              Product Photography
              My Acreage Bird Photographs

              Comment


              • #8

                Re: Downdraft sanding table help suggestions needed

                Re: Downdraft sanding table help suggestions needed

                Originally posted by Don Kondra View Post
                ...I decided to make my new hand tool work bench a sanding table also...

                Basically it's a 2" x 2" frame with a pegboard box that's 44" long, 16" wide and 12" high. I enlarged the holes of the pegboard to 3/8" on the top and two rows on the top of the sides. It will hold a piece of sandpaper to the side when the dust collector is running
                Don, I'm curious as to why you decided to use pegboard for the sides of the box, as well as the top. Was the intention for the sides to draw into the DC any sanding dust that escapes from the top?

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                • #9

                  Re: Downdraft sanding table help suggestions needed

                  Re: Downdraft sanding table help suggestions needed

                  Basically, yes.

                  Normally when I'm sanding a piece, it is held between two bench dogs on the edge of the bench.

                  There is always some sawdust that falls down the side of the bench, hence the holes in the sides too..

                  Cheers, Don
                  Don Kondra - Furniture Designer/Maker
                  Product Photography
                  My Acreage Bird Photographs

                  Comment


                  • #10

                    Re: Downdraft sanding table help suggestions needed

                    Re: Downdraft sanding table help suggestions needed

                    You do not need a lot of CFM for a downdraft table---all you really need is something that will create a negative pressure under what you are working on. Too bad I dont have any pictures but I one made up one with a million holes in the table and it sounded like the Seven Dwarfs whistling "off to work we go" Never thought of the pegboard--great idea and it also comes with 1/8" holes .

                    Believe it or not if you get a table set up properly---the downdraft will actually hold a "flatpiece" while you are sanding
                    "Born 50 years too late"

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                    • #11

                      Re: Downdraft sanding table help suggestions needed

                      Re: Downdraft sanding table help suggestions needed

                      Hay Mac,

                      The pegboard has 1/4" holes, all the top holes and the first two side rows were enlarged to 3/8".

                      A dust collector doesn't really "suck", it works by moving a volume of air and if you reduce the volume of air available you reduce the effectiveness of the unit.

                      I performed a very scientific test to fine tune how many holes I had to enlarge. Without enlarging any holes the table would "suck" cigarette smoke from three inches away. With the top holes enlarged it would suck from about five inches away.

                      With the first row on the sides enlarged it would suck from a little over six inches, enlarging another row didn't make a noticeable difference so I stopped there....

                      And there is no whistling

                      Cheers, Don
                      Last edited by Don Kondra; 11-17-2008, 04:47 PM.
                      Don Kondra - Furniture Designer/Maker
                      Product Photography
                      My Acreage Bird Photographs

                      Comment

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                      • #12

                        Re: Downdraft sanding table help suggestions needed

                        Re: Downdraft sanding table help suggestions needed

                        I want to thank all that responded to this thread, before I started I did search the forum and went through a lot of posts getting some ideas and now with all the responses I have I am back to the drawing board to think out where I might go now. I was originally thinking that I would be making a complete stand alone unit and now I am inclined to look at something that could be the top of something or hinged on a wall and plugged into the dust collection system. Part of the problem is in a small shop you have limited wall space or just space period and everything that takes a footprint in the shop has to preform many functions and or store supplies.

                        thanks for your input

                        Jake

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                        • #13

                          Re: Downdraft sanding table help suggestions needed

                          Re: Downdraft sanding table help suggestions needed

                          Hey Don---I wasn't kidding---I was being serious---you should try it hooking up to a Murphy 7 HP Dust Collector This was years ago when in the curious stage. It took a few days of tweaking and I finally got it to work.
                          "Born 50 years too late"

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                          • #14

                            Re: Downdraft sanding table help suggestions needed

                            Re: Downdraft sanding table help suggestions needed

                            "Pie R squared" is the formula (haven't got a clue where those fonts are) for area of a circle

                            When I built mine, I just added up the amount of 1/4" holes in my top vs the 4" pipe feeding it and discovred I was a bit undersized in my downdraft table. I never did get around to increasing the hole sizes but it still works great. That's the problem when you try it before you finish it, it all of a sudden becomes good enough.
                            Paul

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                            • #15

                              Re: Downdraft sanding table help suggestions needed

                              Re: Downdraft sanding table help suggestions needed

                              Originally posted by big mac View Post
                              Hey Don---I wasn't kidding---I was being serious---you should try it hooking up to a Murphy 7 HP Dust Collector This was years ago when in the curious stage. It took a few days of tweaking and I finally got it to work.
                              LOL

                              That's not a sanding table, it's a Vacuum Table

                              No need for a vise and bench dogs

                              Cheers, Don
                              Don Kondra - Furniture Designer/Maker
                              Product Photography
                              My Acreage Bird Photographs

                              Comment

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