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  • Vacuum for Vacuum Table

    My almost free shop vac died tonight. So I'm looking for something that'll run a small vacuum table, about 5"x12". The vacuum table was designed for a shop vac hose, but I'll change things if I need to.

    The vac was rated around 1.25 HP (not that it ever developed that) and worked quite well.

    The vacuum needs to run for many hours at a time. It takes several hours for the mill to finish cutting and the vacuum table needs to be on the whole time. I'd also like something as quiet as possible.

    Any suggestions for something less than $100?

  • #2
    Originally posted by Puckdropper View Post
    I'm looking for something that'll run a small vacuum table, about 5"x12".

    The vacuum needs to run for many hours at a time. I'd also like something as quiet as possible.

    Any suggestions for something less than $100?
    100% duty cycle for hours of operation? Quiet? A budget of $100?

    I don't know of a vacuum intended for cleaning purposes that meets these criteria.

    However.

    A blower salvaged from a residential forced air furnace (either powered by its OEM non-cooled open motor or a totally enclosed fan-cooled [TEFC] motor), some plywood and a little effort could present you with some possibilities.

    Check with HVAC companies or scrap yards for furnaces pulled out of homes because of failed heat exchangers.

    Some may have variable speed direct drive motors that are integrated with the blower, the motor mounts within the fan wheel and drives this directly. Those are too new-school for me, maybe you are more comfortable with the added complexity of their so-called simplicity. My preference runs toward the traditional fixed speed blower that is belt-driven by a separate motor. Whatever.

    I bring up the matter of open uncooled vs enclosed cooled motors because people might otherwise overlook the fact that the open uncooled motor is cooled in a furnace by filtered air the blower is pulling past the uncooled motor. If you build an enclosure for the blower/motor and maintain similar air flow when you adapt it for your vacuum, the uncooled motor can be expected to give good service life. Otherwise, consider using a TEFC motor.

    Will a furnace fan pull sufficient vacuum for a 5 x 12 table? I think you will need to provide a sliding panel or some other kind of by-pass control valve mechanism to keep from stalling a residential blower. I expect there are ways to verify whether I'm right before spending money or effort.

    Certainly bound to be MUCH quieter than any residential/commercial cleaning vacuum that I've ever encountered.
    Last edited by EddyCurr; 03-07-2018, 09:42 PM.

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    • #3
      I have a 6 1/4" squirrel cage fan and a small motor that goes with it (but I can't find the motor.) If I was to guess, I'd say that motor was about 3-4" in diameter and rated something like 1/16 HP. I've also got a 1/3HP sump pump motor, 1750 RPM and maybe standard speed 1/4 HP motor. (Thanks Grandpa!)

      Am I in the ballpark with these parts as far as cobbling together a pump?

      What should I expect price-wise for a commercial pump?

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      • #4
        I have used a small air compressor (Gast) many times for this duty. Be sure to cover unused holes.
        Hook up the intake to the vac table.

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        • #5
          a tap water to vacuum contraption will be quiet. not sure about the economics, though.

          and a pluged vac will not survive for very long. it overspins and has no cooling.
          Last edited by dian; 03-08-2018, 12:32 AM.

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          • #6
            Not $100.. but these will pull 29hg at 1.15 cfm, and run forever. I have handful of these in service at work and one at home for my vacuum jigs

            Gast DAA-715A-EB

            https://www.coleparmer.com/i/gast-da...g-115v/0706111


            you can get various simlar used models on ebay $200-300.

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            • #7
              Originally posted by lakeside53 View Post
              Originally posted by livesteam View Post
              I have used a small air compressor (Gast) many times for this duty. Be sure to cover unused holes.
              Hook up the intake to the vac table.
              Not $100.. but these will pull 29hg at 1.15 cfm, and run forever. I have handful of these in service at work and one at home for my vacuum jigs

              Gast DAA-715A-EB

              https://www.coleparmer.com/i/gast-da...g-115v/0706111

              you can get various similar used models on ebay $200-300.
              I'll agree there's a lot in favour of livesteam's and lakeside53's suggestion to get a Gast or similar industrial vacuum pump if you can swing it.

              I have an old JB Industries DV25B that was used for evacuating A/C systems. Runs on 115VAC and is rated for 29.9 IN HG at 1.5 CFM. It cost a lot more than the OP's budget figure of $100. But that was then, this is now - I see one tonight on eBay for a buck-fiftyish.

              Maybe livesteam and lakeside can speak to their experience with vacuum pump upkeep. For A/C use, good maintenance practice has to be followed for pump longevity - oil changes immediately after every evacuation use, refilling with oil suitable for vac applications.

              Pump components are serviceable. So a used pump that hasn't lived well ought to be able to be restored to good condition (at some cost in addition to acquisition price.)

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              • #8
                If your vacuum table is really airtight you can use even old fridge compressor. More "vacuum" than shop vac but less cfm.

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                • #9
                  I was going to suggest that. It takes a while to pull the vacuum but it'll do the job if there are no leaks.
                  ...lew...

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                  • #10
                    Another thought - what about re-powering the dead shop vac with a motor that has suitable duty cycle/cooling?

                    That vac was integrated ino your present set-up and worked adequately until the motor's magic smoke escaped. Perhaps opening up the dead vac might reveal some opportunities.

                    No need to look original (or pretty.)

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                    • #11
                      Originally posted by MattiJ View Post
                      If your vacuum table is really airtight you can use even old fridge compressor. More "vacuum" than shop vac but less cfm.
                      Most of the residential compressors are 1/4 Hp or less, not much use as a high volume vacuum.
                      Retired - Journeyman Refrigeration Pipefitter - Master Electrician - Fine Line Automation CNC 4x4 Router

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                      • #12
                        I think he said 5 x 12 inches, not feet. For that a cheap way out (not good) is just another shop vac. Please do not use a blower from a furnace or AC unit, they are air over cooled and will quickly overheat and burn out. Gast as someone else suggested makes a good rotary vane vacuum pump. BUT since it could be drawing in dust or chips, may not be the solution.
                        Last edited by wmgeorge; 03-08-2018, 09:45 AM.
                        Retired - Journeyman Refrigeration Pipefitter - Master Electrician - Fine Line Automation CNC 4x4 Router

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                        • #13
                          Originally posted by wmgeorge View Post
                          Most of the residential compressors are 1/4 Hp or less, not much use as a high volume vacuum.
                          Didn't I just said so?

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                          • #14
                            After digging through my options, Venturi-style vacs (could be useful, I use compressed air on the bit to keep the plastic from sticking), vacuum pumps designed for much larger tables than mine, etc. it's looking like the Ridgid WD1450 vac will solve my problems nicely. It's got a separate fan to handle cooling the motor so should be able to handle long run times.

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                            • #15
                              Don't forget to have a vacuum gauge with electrical output to stop the machine if the pressure rises above a preset safe level.

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