Spraying Primer - single stage or 2 stage air compressor

Discussion in 'Body Restoration' started by Chuck71RS, May 17, 2017.

  1. Chuck71RS

    Chuck71RS Veteran Member Lifetime Gold Member

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    Will both approaches below work with the single stage 60gal tank, 3.7hp compressor motor, providing 13.4 cfm? Is a 2-stage compressor needed?

    Will work one piece at a time (strip, block, epoxy, body work) off the car (except rear qtrs, rear and trunk jams) then high build primer. Because of Houston humidity, don't want to strip and block sand the entire body before the epoxy

    Two approaches to spray the primer
    1. Spray with the motor plugged in and let the motor cycle. Type_1976LT said the heated air would not be a problem with the proper set up. His recommendation was a 3/8" hose 50 feet long, a water filter and possibly a desiccant filter

    2. Unplug the compressor motor after the tank is fully pressurized (155psi) and spray with only the cfm in the tank. Reason for this approach is to avoid heated air

    There is 7 minutes of spray time using the large tip gun from Type_1976LT which uses 7cfm at 40psi. To remain above min cfm available for the gun, use 49 of the 56cfm. The Binks website states one cubic foot of air is reduced in volume 1/11 when pressurized at 150psi. A 60gal tank holds 88cubic feet at 150psi and 32 cubic feet at 40psi giving 56cfm for use. The actual results will probably be different but the calculations should be close enough to show the spraying can be done this way.
     
  2. jimrr

    jimrr Veteran Member

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    Plug it in and spray away... it's primer. Especially if onlydoing a panel.
     
  3. larrylarry

    larrylarry Veteran Member

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    My compressor I used to paint my 78 is 45 gal. 2 hp motor. It's on one side of the garage door, ran 3/4 steel pipe up & over the garage door then down the other side where it's goes into a water separator/filter. This is about 25 ft of pipe which cools the air. I also changed all the connectors from 1/4 to 3/8, a little bit extra air flow. Didn't use any extra air filters or desiccant filters. I didn't worry about the compressor cycling which it did during painting as long as I had 22-24 psi at the gun. I shot epoxy primer on the body with doors & trunk lid on, did the front fenders,hood & front bumper separate. The body,trunk & doors takes 28 oz of primer for one coat.
     
    Last edited: May 18, 2017
  4. Bandit723

    Bandit723 Veteran Member

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    I use a 5HP unit with a 60 gal tank. Has kept up with every thing that i have thrown at it. I did also go the route of running some cooling pipe with drains on them as well. Really helps keeping the moisture out of your tools.

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  5. giggity

    giggity Veteran Member

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    Ive got the same compressor, and I ran about 50 feet of 3/4 steel pipe, at and put 2 40 micron filters back to back, and then another 40 foot of hose, and I still get moisture. I think the humidity here is much worse though, right now its at 85 degrees and 70% humidity. My sand blaster doesnt gum up completely, but you can tell the dry days from the humid days for sure. I will need to add a desiccant filter and/or a dryer when i get ready to paint. Or try doing the copper tubing like you did.
     
  6. Bandit723

    Bandit723 Veteran Member

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    I would be happy to take the 85 degrees right now weather guy's are talking 30's tonight. This setup is not perfect but does catch a lot of moisture. I do drain the tank copper pipes and filter every couple of runs and have not seen any moisture blowing out of my tools. I do use a desiccant filter on my spray guns. No moisture issues.
     
  7. giggity

    giggity Veteran Member

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    Ive seen several setups using the copper tubing, and it seems the best way to remove moisture. Did you braze it yourself?
     
  8. Bandit723

    Bandit723 Veteran Member

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    Yes I did...is pretty easy
     
  9. Edem_Alive

    Edem_Alive Veteran Member Lifetime Gold Member

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    I also have a quincy with about 30 feet of copper tubing and get a little water after about an hour. It is much better than w/o. I can drain the water from the pipes and the compressor and go for another hour pretty easily. These comps are awesome!
     
  10. Edem_Alive

    Edem_Alive Veteran Member Lifetime Gold Member

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