Adjusting air on a Astro EVO LPLV gun

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PostPosted: Tue May 06, 2008 8:58 pm
'68 Coronet R/T wrote:Ryan,
The volume of the air (Cubic Feet per Minute) is what is critical not the PSI. You can pressurize a small amount of air to 125 psi but once you open the valve that small amount of air escapes so quickly that what little volume (quantity) of air you had is gone.
Your compressor should state on it somewhere what the CFM output is at say 40 psi.

Mooch wrote:Compressor is a $99 3HP 21Gal Harbor Freght unit

I told you in the very beginning it was your compressor. You just can't spray with that compressor .

Mooch :!:

I don't know crap about body work but pretty good at math. The epoxy, 2k, and Base all went on great. Even my last 2 passes of clear went fairly well. I just blocked it with 400 wet, someone good at sanding and buffing could probably make it look great how it is now :?: As it is I want to lay down down two more coats. Gun issue has nothing to do the compressor. Doesn't matter how big the motor on the compressor is, turn it up to 120psi and cut off the compressor and pull the trigger for couple seconds to test gun, 120 is 120. My issue was after that in the valves/lines/gun. My regulator on the tank was so restrive how it was setup up I could set the gun at 80psi and only get 21psi out, open the valve up now and I'd pass 21 psi with the regulator set at 35psi or so. Big restriction there. I understand now that SPI Universal is a high solids 52%? clear and they recommend it put on really heavy and Barry was recommending trying upwards of 26psi at the gun instead of 19-21psi I was experimenting with. I think my problems are more that I could put the other products on wth multiple lighter passes and that is not working with the clear. I'm pretty sure I'm the problem not the compressor. A pro who is on the trigger 95% of time has a higher air requiremet than someone is a slower mover, or going slow and pausing so their compressor can keep up. In any case the lowest my compressor gets while spraying is down to ~75psi, It is at 80-95psi most of the time spraying. If my gun is working good at say 25psi with trigger pulled, and I can maintain that with trigger pulled down within the psi range I know the compressor will be in, then I should be OK from a compressor standpoint. Should be easy to test for start at 90psi and hold it down long enough to drain the tank down to 75psi and see whats its at on the gun the entire time. :) Thanks for all the help everyone, I think what I have can work, just need the skills to make it work.

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PostPosted: Wed May 07, 2008 10:11 am
It doesn't matter what PSI your compressor can maintain if its not putting OUT enough CFM. Of course its going to drain slowly if you have restrictive lines or regulator! There are all kinds of math experts on here, most of them lack common sense.

Until you test your Gun properly, its just wasting our time trying to shoot at the dark with the problem. It keeps coming back to your compressor or plumbing.

You still haven't taken any pics of your equipment, so we have no idea how it is really plumbed. You can "get away" with a small compressor, as long as EVERYTHING is setup right. I've used an old 20-gal myself on panels, with no troubles, BUT I was running it wide open, NO regulator on the compressor, no excessive fittings or adapters....straight thru to my gun reg. I would not recommend this! Its the only way I could get the gun to spray right on my small rig. It was a one time only rig, not the way to do it right.

Take your gun to work or someplace that has a high volume of air. Clean it well and test it out.

These LVLP guns don't spray fast like a HVLP. Less material output.....but the savings is in the lack of overspray and how much material they actually lay down. You'll have to paint slower, but it shouldn't be a turtle's pace, there is something wrong with your setup. Suspect the gun last, in this case. ;)

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PostPosted: Wed May 07, 2008 1:54 pm
Going to spray again soon, manufactor (SPI) recommend wait 2 days - 1 Week, sand 320-800, wait another day and respray. Started sanding some last night. I can adjust gun freely now that I opened up regulator on tank. I think I'm going to remove regulator on tank, valve and quick connect and run hose strait to output and use the regulator on gun side with the just the bubble filter at gun to be safe as you think will work better.

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PostPosted: Wed May 07, 2008 5:40 pm
Throw those "Bubble filters" in the trash. They'll just make you look like you don't know what you're doing :twisted:
Just walk away....

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PostPosted: Mon May 12, 2008 8:10 am
I finished. Pretty happy with it, orderd a buffing system and bought some sandpaper to colorshand with. Learned a lot! and think I can do much better next time. Just sprayed with the line setup exactly how it was before, except with the regulator on tank full open. Lots of paint left over



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PostPosted: Mon May 12, 2008 8:37 am

That look darn good for your first time spraying. I hope mine turns out just as well as yours when I go to spray her with my new gun.

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PostPosted: Mon Jun 16, 2008 1:13 pm
I sprayed my Mazda Tribute this weekend.
Silver $31 QT of Omni (used 2/3s of can)
Gray $19 Pint of Omni (used half of can)
Clear $95 Gal+ kit Refinisher's Select RS6040 (used half)

I may have had enough SPI universal to do entire job, maybe should have tried it again, not sure. This laid down really slick, good enough that I didn't have to cut or buff, it fine for my usel. I had 1 run area I sanded and buffed later. I tried to work slower to keep tank pressure up. I think I'm going to sick with this clear.


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