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DIY Hopper for the Caswell gun

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  • DIY Hopper for the Caswell gun

    Hi all...

    An idea i had a while got tested this weekend. I took a glassjar with a stainless steel lid, plugged in a coulpe of hydraulic connectors, welded a pipe to the air inlet that goes to the bottom, plugged in the bottom and 6 tiny holes drilled from the sides to make the powder really get turbulent in the jar, and woila, a hopper for the Caswell gun for under $10...

    Does it work? Yes, really good by the way, it holds easy 1 litre of powder, and flows much more even than with the original can on the top, also, the benefit i was after, you can tip the gun in every direction and the flow stays the same. Takes a bit more pressure, used 2 bar with original cup, and 3 bar now.

    WEIRD Performance & Coatings

  • #2
    Thanks for the tip, and congratulation on your "discoverie"


    • #3
      Originally posted by Netnut
      Thanks for the tip, and congratulation on your "discoverie"
      This has been done before, there was some kits on Ebay a while back, but this is cheaper and works just great, any jar with a stable enough lid to fasten the connetors will work...
      WEIRD Performance & Coatings


      • #4 sells them
        they are more expencive cuz they work like a fluidized hopper.


        • #5

          We have a similar setup that works well.


          • #6
            what kind of control unit is that
            and how did you conected it to a hobby gun ?
            now that's what I call interesting.


            • #7
              It’s a home brew unit. We couldn’t afford a pro setup so we made our own.
              Started with a PC unit and modified it. The control box has several relays, 24volt control transformer, a couple solenoids, control switches, pressure regulators and pressure gauges.

              The stock PC unit worked fine with the exception of the powder delivery system. We ordered and tried the EW 2 lb hopper and it helped but it still tended to surge and was very touchy to the powder level and air psi. Most of what we spray is large flat box items and even coverage was a must.

              We made or own fluidizing hoppers and that helped delivery but still wasn’t that great. After talking with a few people I ordered a used powder pump. We modified our hoppers to accept the pump and got to work on the control box.

              The control box has a hand valve, water trap and a drier on the back. The pressure is regulated to 60psi where it enters the box. The feeder line is split inside the box and goes into two solenoids.

              The #1 solenoid goes to a regulator that’s adjustable from the front with a psi gauge. This is the fluidizer pressure regulator and its solenoid is activated by a toggle switch on the front. The air then exits the back of the box and goes to the fluidizer connection on the bottom of the hopper. Depending on how much powder is in the hopper it’s normally set at about .5 psi.

              The # 2 solenoid feeds two pressure regulators and gauges on the front. These are for the powder pump, they both exit the back of the box, one feeds the siphon side of the pump and the other feeds the dilution side. These are usually set around 3 to 5 psi each. A switch mounted to the trigger of the gun activates the # 2 solenoid.

              Next was to modify the stock PC unit and gun. We disassembled the stock control box and mounted the power section inside our box. The face of the stock unit was mounted inside our box with the front exposed, that way we could access it’s power switch and be able to see the LEDs on the front. The foot switch was disconnected and ran through a relay, the switch on the trigger of the gun activates the relay. We made it so the gun could be completely removed from the box. That almost worked; need a better high voltage connector… We removed the cup and lid from the stock gun and cut off the U bend. Installed a nylon barb on that tube so we could slide on different hoses that go to the powder pump discharge. We also out a cap on the old cup psi feeder tube.
              That’s it and it works fantastic
              I’ve been looking around for a larger power supply for the gun 50-100kv without much luck.


              • #8
                Can anyone show how a fluidized hopper works exactly? some schematics?
                WEIRD Performance & Coatings


                • #9

                  It's pretty simple, air blows through a micropore plate.


                  • #10
                    Popeye hats of to you
                    that is one impresive developed idea
                    if you need a trasformer I have a broken nordson versa spray control unit that still has everything on it
                    I bought it as a damage unit just to have spare parts for my main versa spray and it's been sitting on my closet for 1 year now
                    if you want it PM me maybe you can fix it or atleast take the trasformer out .


                    • #11
                      Thanks Jtagger19!

                      The kind words are much appreciated.

                      PM on the way


                      • #12
                        CASWELL Inc will hopefully be able to offer you a hopper for their DIY gun shortly.
                        Mike Caswell
                        Caswell Inc
                        Need Support? Visit our online support section at


                        • #13
                          That's Great!
                          You might want to consider picking up a line of powder pumps, that takes the hobby gun to a whole new level.

                          Excellent site by the way, great customer support.



                          • #14
                            I ran into this a few weeks ago, it was on sale for $39. I wonder how well it would work for a conversion?

                            Harbor Freight buys their top quality tools from the same factories that supply our competitors. We cut out the middleman and pass the savings to you!


                            • #15
                              Popeye & Zpider could you guys show us a close up shot of how you attached the line from the hopper to the gun? TY

                              Drive It Like You Stole It