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Thread: How to plumb this vacuum pump

  1. #1
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    How to plumb this vacuum pump

    I've never used a vacuum pump and am embarrassed to say that I am perplexed at how to plumb this 2-stage Gast pump. I bought it "used" from a guy who claims it has never been used, and it looks brand new. It has 2 inputs and 2 outputs. Anyway, as given to me, it has the 2 outputs are plumbed together with a single open end where air exhausts. The 2 suction ports each have "can" intake filters attached.

    I'm unsure how to plumb it for a vacuum chuck. Do I simple parallel the intakes together like the outputs are? Or do I feed one output to the input of the second? I cannot find any information in the pitiful manual that I've found, and I haven't found any images that point to how to plumb it. I'm guessing I'll get more volume in parallel and more suction in series. Any one know and willing to help? The pump is a Gast dual stage diaphragm pump model BFB-DAA-P716A-EB. Photo below shows the outputs plumbed together as described.

    Last edited by tom lucas; 01-16-2020 at 6:06 PM.

  2. #2
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    Looks like that pump can be used as either an air compressor or a vacuum pump: https://gastmfg.com/products/compres...diaphragms/daa

    Perhaps the operating manual on this page will help: https://gastmfg.com/products/compres...anchor-section

    If someone here doesn't know and if you need any other vacuum chuck components, maybe contact the Frugal Vacuum guy to buy them then ask him how connect to that pump. I think he would know.

    JKJ

  3. #3
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    Quote Originally Posted by John K Jordan View Post
    Looks like that pump can be used as either an air compressor or a vacuum pump: https://gastmfg.com/products/compres...diaphragms/daa

    Perhaps the operating manual on this page will help: https://gastmfg.com/products/compres...anchor-section

    If someone here doesn't know and if you need any other vacuum chuck components, maybe contact the Frugal Vacuum guy to buy them then ask him how connect to that pump. I think he would know.

    JKJ
    Thanks for the help. I had read the manual before posting this thread and it tells you nothing about use or plumbing. Useful to rebuild, if needed. Otherwise largely a useless document.

    I've kept looking. I've seen a photo of one with the inputs in parallel. I also found a for sale description that basically says more suction in series, more volume in parallel.

    And yeah, I think you can use it as a compressor, but don't care about that right now.
    Last edited by tom lucas; 01-16-2020 at 7:14 PM.

  4. #4
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    I went to eBay and bought the same pump, so we'll figure it out....

  5. #5
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    Quote Originally Posted by tom lucas View Post
    I've kept looking. I've seen a photo of one with the inputs in parallel. I also found a for sale description that basically says more suction in series, more volume in parallel.
    I suspected that since it looks like two independent pumps connected by a common motor. Should be easy enough to try both ways to see what works best as a vacuum chuck.

    You'll need to add a little manifold between the pump and the lathe with a gauge and a breather valve to control and monitor the pressure (but I suspect you already have that planned!)
    Joe Woodworker has some nice descriptions and photos:https://www.joewoodworker.com/veneer...umchucking.htm

    JKJ

  6. #6
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    In addition to what John Jordan mentioned, I would also add a filter on the input line and perhaps a low-restriction noise muffler on the output (PVC tube with some cloth in it). I went to the local auto store and bought a universal (larger) gas line filter. I oriented the filter so that I could see the eventual build up of dust in the clear filter.

    On my first attempt to make a vacuum system I bought some supposedly good "sealed" bearings. In actuality they were "non-contact" sealed bearings. In other words, there was a very small gap between the rubber seal and the center hub. According to the bearing distributor (VXB?) they are the most common type of sealed bearing. Great for nearly all applications except for a vacuum system. Some people have put separate seals in front of the bearings. I could only draw about 5" of Hg. with my non-contact but sealed bearings. Worthless. I thought that if I let it suck in some heavy axle grease that it would fix it. It didn't.

    I ended up buying very good sealed bearings from the Frugalvacuumchuck fellow (Bob Leonard). Reasonable price and he had already attached a piece of hard poly tubing. I connect and disconnect to the system with just press together (one inside of the other) poly tubes. The nesting tubes make a good enough seal that I can draw about 27 inches of Hg out of a theoretical ~ 28 inches (we live at about 1750 feet above sea level). The Frugal bearings are good enough that today when I turned off the pump it took over a minute to finally let go.

    BTW, you will absolutely LOVE your vacuum chuck and will wonder why you waited so long.

  7. #7
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    Tom, I post a picture of my setup later. For info, plumb the two vacuum lines together just like the pressure side is done. You will need a liquid filled vacuum gage, automotive gas filter, and a bleed valve. I just put a hose barb fitting on the pressure output and that greatly reduces the noise.
    When working I had more money than time. In retirement I have more time than money. Love the time, miss the money.

  8. #8
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    Here is a picture of my setup. The vacuum and pressure heads are tied together. This is a Thomas 2660 pump. You canít see my gas filter in this picture. It needs to be near the rotary adapter to help keep the tubing going to the pump clean. I donít have a filter on the bleed valve, but maybe should add one. I highly recommend a liquid filled vacuum gage. If not liquid filled the gauge will joggle rapidly and eventually wear out the gauge. I have a toggle switch that I has a magnetic base that I place on the lathe head when in. use. I put a valve labeled not needed and it has no function unless I would want to see how well the vacuum was holding without the pump. Really has no use. The hose barb on the pressure side is the muffler. It creates a little resistance to the output flow that really quotes the pump. My rotary adapter was initially used on my Laguna 18-36. I sold that lathe, but kept the adapter for my Robust and made an adapter so it would fit the Robust. That is why it might look a little strange.

    5829F78A-A537-4CD9-B01F-6CAD95DD2984_1_201_a.jpg
    Last edited by William C Rogers; 01-17-2020 at 2:56 PM.
    When working I had more money than time. In retirement I have more time than money. Love the time, miss the money.

  9. #9
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    William, thanks for posting a photo of your setup. After staring at several photos of these pumps, I see that many of these 2 stage varieties have pipes integral to the pump heads such that inputs and outputs are tied together. On my pump, I guess to accommodate many uses/configurations, they've left the plumbing for the user to do on the outside of the heads. This is where I became confused. So, now I just have to decide how I will connect to my lathe. I like the JT turning tools adapter & hub. I've asking for a price for my lathe. However, frugal vacuum setup is far cheaper.

    I really like the filter offered by JT in the kit, but not sure about buying the whole kit. I tried to find a similar filter online but have had no luck with that one.

  10. #10
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    Tom, the Thomas use to be made the same as yours with the heads independent. Most are now plumbed together.
    When working I had more money than time. In retirement I have more time than money. Love the time, miss the money.

  11. #11
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    Quote Originally Posted by tom lucas View Post
    I really like the filter offered by JT in the kit, but not sure about buying the whole kit. I tried to find a similar filter online but have had no luck with that one.
    When you said you "had no luck with that one" did you mean you tried one and it didn't work or did you had no luck finding one?

    If the latter, would an in-line fuel filter work? There are lots of those available, even on Amazon. Most appear to be sealed disposable filters.
    https://www.amazon.com/s?k=inline+fu...ref=nb_sb_noss

    I know the fuel filters on some of my diesel engines look much like the one in the JT picture and will certainly pass air and I'm certain it will stop dust. And they have replaceable elements. Maybe that's what JT uses.

    Or maybe JT will sell you just the filter if you call.

    JKJ

  12. #12
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    Quote Originally Posted by John K Jordan View Post
    When you said you "had no luck with that one" did you mean you tried one and it didn't work or did you had no luck finding one?

    If the latter, would an in-line fuel filter work? There are lots of those available, even on Amazon. Most appear to be sealed disposable filters.
    https://www.amazon.com/s?k=inline+fu...ref=nb_sb_noss

    I know the fuel filters on some of my diesel engines look much like the one in the JT picture and will certainly pass air and I'm certain it will stop dust. And they have replaceable elements. Maybe that's what JT uses.

    Or maybe JT will sell you just the filter if you call.

    JKJ

    I surrendered and bought the one from joewoodworker. I'll have to add barbs, but it will work just as good. The disposable ones just look kinda puny and perhaps more restrictive or quicker to clog. Though, I see that a lot of people use them with seemingly great effect. I like being able to take the filter out and clean or replace it without undoing plumbing.

  13. #13
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    That is probably a good move. I’m familiar with the Thompson and Gast piston pumps, but not with the Gast diaphragm pump you have. For the piston pumps the disposable fuel filters are ok. I’m going to move my filter to just before the pump. As it is now I am keeping the tubing clear, however I’m measuring vacuum between the filter and the pump, not the vacuum chuck.
    When working I had more money than time. In retirement I have more time than money. Love the time, miss the money.

  14. #14
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    Tom

    You have a process system sample pump by GAST, a pretty nice one actually.
    It will draw a vacuum and it will discharge air, and is designed to be positioned in a bypass loop ,sample stream, for a gas system to The pump will pull the sample through an analyzer and discharge it back into the process stream.If I was at work I could show you the models we use to pull air samples through radiation detection skids.
    Leave the two heads connected and turn it on, you should have vacuum on one side and a discharge pressure on the other side. It's pretty easy to figure it out.
    The reed valves inside those diaphragm operated pump heads are kind of noisy.If you ever take them apart they have a very specific orientation to them. I've done dozens and dozens of pump rebuilds on that style of GAST pump. Not that exact model.
    I might be able to find a pump, exploded view, in an old tech manual, but they're not that complicated. I'll look Tuesday for one.
    Last edited by Mike Cutler; 01-18-2020 at 9:16 AM.
    "The first thing you need to know, will likely be the last thing you learn." (Unknown)

  15. #15
    Checkout the Oneway system at https://oneway.ca/pdf/Part%202977%20...Dec%202010.pdf. - John

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