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Air hose diameter for HVLP spray gun

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  • Air hose diameter for HVLP spray gun

    I am planning to paint an old tractor that I am restoring, I want to run a air hose from my garage, out to my barn where the painting will take place, the distance is about 130 feet. Where can I find the pressure drop or volume of air passable for a given ID hose? The plan is to use a 1/2 or 3/4 ID hose 130 feet long, filter/regulator, and then a shorter length of 3/8 that will then connect to the HVLP paint gun.

    As always, thanks for the help

    Bob

  • #2
    It will have a pressure drop of about 20 psi and a capacity of about 19 cfm assuming 100 psi input and 3/4" ID. See table here:

    http://www.coleparmer.com/techinfo/t...es.htm#anchor4


    [This message has been edited by Evan (edited 03-04-2004).]
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    • #3
      Evan,

      Thanks for the link!!

      I searched high and low and never found anything good.

      Great link!! Thanks


      Bob

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      • #4
        You shouldn't have a problem with an HVLP spray gun. In fact, the extra length will help remove compressor air pulsing during long shoots. Just make sure your compressor can keep up with the gun you have.

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        • #5
          The link with the friction loss is great! It only goes down to 1/2 hose. Does any one know the friction losses for 3/8 hose?

          Thanks Bob

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          • #6
            The friction loss is approximately exponential to the second power so if you make the ID 1/2 as small the loss goes up four times.
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            • #7
              The bigger the i.d. of the line the better. Less drop (obviously) and more capacity. Make sure your air dryer is at the gun or close to, not on the other end near the compressor tank. With 130' of line your air will cool quite a bit on the way to the barn and the best place to pick up the condensate will be at the barn...
              I figured out that all pans are \"no stick\" if you \"no cook\" in them.

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              • #8
                Hey guys,

                Thanks for all the help. Here is how I finally made out.

                I burried a 1 inch line to the barn (100 feet). Then the compressor is in the garage. I have a shut off for the barn or the garage, my choice. I have a Sharp paint filter at the barn and will put a lubricator in time. Lubricant will be separate from clean air for painting. My compressor makes 20cfm, my gun uses 13cfm. Now I need to set up the paint booth, I have a air handler on the way, wish me luck!

                Bob

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                • #9
                  Geez Bob, that seems like a big expense just to paint a tractor. Are there no paint shops near you? Besides your paint booth, if you intend to use "hardner" in your paint, you'll also need a fresh air supply and full body coverage for yourself.

                  Don't take chances with the cynoacrylates--it is 20 times as toxic as arsenic. This stuff was never meant to be shot in a home shop by "newbies". Make sure you wear your gear while mixing as well as spraying. By the time you find out that you may be alergic to it, it's too late. Also, the exposure can be accumulitive.

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                  • #10
                    Bob,
                    FOr the booth I used 1" sch 40 pvc pipe and 4mil plastic sheet -worked fine. Also, 3 20x20x2 inch furnace filters for the intake and a fan blowing air out through a port to complete the negative pressure booth. You have plenty of reserve air for your gun which is good. You also need some water traps between the compressor and your Sharpe filter.
                    This shows a recommendation for shop piping:
                    http://www.sharpe1.com/dr-pipe.htm

                    Ken

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                    • #11
                      Hey guys, thanks for the help and link. I too am using the Sharp stuff. Not quite as elaborate but good for what I do. I also have a fresh air system so I can shoot the new paints and clear. I am just finishing the motor on the tractor, once I get to the tin work and then paint, I will post a pic. Hopefully by summers end.

                      Thanks again Bob

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