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Checkerboard

Discussion in 'Spraying / Gun Cleaning' started by JWolfe, May 26, 2017.

  1. JWolfe

    JWolfe Member

    I'm going to throw this out there I've been spraying for over 20 yrs I'm far from a pro I learn something every day that said for at least a year I've had trouble with everything I spray base clear 2k epoxy doesn't matter it makes a checkerboard pattern can't seem to shake it used every gun got hi flow fittings 150 psi wall it's about to drive me nuts open to suggestions
     
  2. By checkerboard do you mean variance from light to heavy within the fan pattern? (hope that makes sense) Every gun is the same? Logic would conclude that it is something upstream of your gun. Does your pressure jump around when pulling the trigger? Regulator, wall filters, desiccant systems have been known to do similar to what you are describing when they go bad. (corrosion) What type of piping are you using? Could possibly be a obstruction of some type in the piping. I'm assuming everything was working good at one point so piping diameter shouldn't be the issue but how long are your piping runs and what diameter pipe are you using? Is your paint hose good? Hose could be collapsing internally intermittently. I'd start looking at everything going backwards from your gun. Bound to be something there.
     
  3. JWolfe

    JWolfe Member

    1496507240964-382352564.jpg
     
  4. JWolfe

    JWolfe Member

    This is what is happening Chris I hope the pic will show it
     
  5. Bob Hollinshead

    Bob Hollinshead Oldtimer

    Atomization problem it appears, does it look like this on the first coat of clear? 2nd? 3rd? Sealer and base going on smooth? Each coat of product needs to go on smooth or you just end up with texture stack up-there is no way of flowing out any texture issues on the end coats with today's paints without ending up with urethane wave.
     
    JWolfe likes this.
  6. Couple of thoughts, dial back your material knob, bump up your air pressure, speed up your passes, tighten overlap to compensate for less material.
     
    JWolfe likes this.
  7. JWolfe

    JWolfe Member

    Bob, I use 50% reduced epoxy for sealer it goes on smooth usually dries a littke blotchy but sight panel no texture base is spies it is thick and it always sprays with a little peel but when sighting down panel appears smooth I'm using iwata ws 400 Evo and entech 75 percent overlap when I clear I do have some peel in first coat but it seems if I try thinner coats it won't lay together finished job uncut no buff doesn't look too bad it's just that there is no what I call scuff and buff because the clear has minor peel that comes off with 2000 easy so it's slick just got the wave unless I use 400 and a block some jobs I just want a quick buff and it's not working thanks for input
     
  8. JWolfe

    JWolfe Member

    Chris I've had the psi up I'm using iwata ws 400 entech and Evo 1.3 they actually are a hoser compared to past iwata guns seems worse at higher psi iwata says with even pattern 1 or 2 psi makes a big difference he suggested to try lowering from 32 to 28 trig pull and will make a big difference I don't see how with high solids tho I can't seem to get it to spray like hairspray do you spray your clear completely wet first pass or lighter coats
    Thanks Justin
     
  9. Jorge M.

    Jorge M. Member

    I use my WS400 1.4 around 28psi , 2-2.25 turns out for fan and fluid anywhere from 3-3.5 turns out from closed, I can't claim to lay it as slick as glass but with little peel or urethane wave.

    Oddly enough I use a SATA RP 5000 as well and the other day I experimented with lowering the spray booth regulator to 80-85 psi and then the gun with trigger pulled at around 28-30. The needle gauge seemed to stabilize and the compressor could keep up with this setting and I sprayed almost a complete BMW M5 with the production clear and it came out way better than I expected. My SATA 5000 RP seems to throw a fit when fed with 120-130 psi at the wall, the Iwata seems immune to the higher pressures at the wall though, weird stuff.
     
  10. I use a 5000RP for clear as well and I've found that I get excellent results setting the gun pressure at the wall regulator. Better than a high pressure at the wall and choking it down at the regulator. I know that Barry recommends high pressure at the wall but I've always had good results setting gun pressure at the wall. If you have a poorly designed piping system with small fittings then the high pressure at the wall may help.
     
  11. jcpettit

    jcpettit New Member

    Sorry to highjack this thread, but Jorge and Chris what settings are you using for your SATA RP? I just recently purchased a 1.3 5000 RP and I cannot get the finish I prefer. Not horrible, but definately needs some adjusting. My last settings were 1.5 turns out 26 to 28 psi, however my pressure on the wall is 130 psi. Came out decent but not like I wanted.
     
  12. Jorge M.

    Jorge M. Member

    I'm 2 turns out on fluid, fan wide open, pressure around 28 psi. Last time I used it I lowered the wall pressure to around 80-85psi and it laid down pretty nice, less blow back and the paint job came out very clean. I have to play more with it, specially with the 4100-1 clear, I mostly spray the 2100 and 5100 clears for production shops.
     
  13. jcpettit

    jcpettit New Member

    I am using the regular Euro (5000) clear mostly mixed 4:1:1 to 4:1:1.5. However, I did use univeral (4000) on the last job I sprayed.
     
  14. 1.5-1.75 turns out approximately 32 pounds at the wall. (no regulator at the gun and the mike opened all the way)Not really sure though as the wall regulator is hard to read. I simply adjust it by feel. When it's adjusted right the gun makes a swooshing sound when you pull the trigger. Not very technical but I noticed that right away when I started using it. What I do with Euro and the 5000RP is mix Euro 4:1:1 sometimes a touch more than 1 part reducer. Normally I use 885 most of the year, when it's hot (like now)I use 895. I go about 1 1/2 -1 3/4 turns out and try to do roughly 75% overlap. I move pretty quickly and I found this works for me. Gives a nearly texture free finish. Best tip for spraying clear successfully is to watch your overlap. Meaning make sure you are overlapping at least 50% with each pass. And make sure you are spraying straight lines. If you are getting too much texture decrease material, increase your overlap and move the gun quicker. Make sure you spray your first coat wet. With high solids clears you need to spray the first coat like how you want it to look. Spraying a "tack" coat is a big no no. You'll never get the dry texture out in subsequent coats.
     
  15. jcpettit

    jcpettit New Member

    Gotcha. Thanks for the help.
     

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