PAINTERS: What air pressure do you spray at?

The question is just that. What air pressure do you spray at and why?

I know where I set my air pressure. I'm just curious as to how others do it and why.

I don't care what the EPA says, what the books want us to spray at or what the manufacturers recomend.

I'd like to know, in the real world, where do you set your air pressure...

 

As of 15 minutes ago in Balto.Md. where we have 29.350 barometric pressure and low humidity (temporary) ,I shot using an air pressure of 22 lbs with HVLP.

Oldmics

 

I'm shooting acrylic lacquer through my OG Model 8 Binks today. No gauge, never had one. I play by ear

 

The correct air pressure is the pressure that is high enough to give you sufficient break up (atomization), and low enough not to cause excessive overspray or irregular streaks in the paint.

Low air pressure will create orange peel and terrible metallic appearance, while high air pressure can dislodge dirt, stir up dirt, screw up metallics and just generally create havoc.

Air pressure is also going to depend highly on viscosity, temperature and gun type.

All that being said, I have almost always had good success with a Graco or Devilbiss conventional gun at somewhere between 40 and 55psi. Under 40 and over 55 generally causes problems.

Don't forget you lose air pressure through your lines (7psi per 25 feet I think) so a gauge at the gun should read different than a gauge at the compressor.

Obviously HVLP guns present a whole new story.

 

In 40 years of spraying I always adjust the pressure at the gun to where it sounds right then shoot a test panel and adjust. Sorry, I've never put a gage on it. Why would you?

 

i have a question for you- how about a heavy metal flake on a fiberglass body. how many coats of clear should i put on ? i will be using a medium flake mix in with clear and then a monster flake done dry with a flake buster. how many coats of clear on top of that should i use to get that real smooth and high gloss look? p.s. never painted before!-- thanks goufos

 

I've been painting over 25 years now and still can't answer that question. LOL! It really does depend on the make of the gun, I have mine set at about 45 coming out of the compressor and anywhere from 12-20 at the gun depending on the type of paint. My guns now are hvlp and are higher end guns, cheaper guns seem to need more air? Just my experience. You do want a little higher if you are shooting metallics. Don't shoot metallics to wet or they will model up (which means the small metallic particals will clump together causing blotchiness. After I spray my last coat of metallic, I always turn the pressure up a little bit and spray a mist coat over the final coat. This allows the metallic to "sit" on the surface and really evens things out if you are a novice painter.

 

wingnutz is right on point, your surroundings where the paint job is being done will determine your airflow, temp for reducers and hardeners.

 

I've never used a gauge when spraying.

 

i painted a friends beater at his house outside years ago, he told me everything was ready all i had to do was show up and spray. he had a compressor, hose, and a binks-look-a-like. no regulator so i sprayed it while kinking the air hose with one hand and spraying with the other. that said, and to answer your question, i don't know the pressure i spray at.

 

I agree with the others. It depends on the conditions. I do show cars for a living, and at different shops I would have to adjust my pressure accordingly. Now that I have my own place I am currently shooting PPG Deltron at 20 psi. I use to use Spies Hecker only, and shot it at 16 psi. So the filter setup and paint will also effect your pressure, but as a guideline, 15-20 for a HVLP setup and 40-45 for a conventional setup. Flake won't be much different pressure wise, but the tip size will make ALL the difference. that will also depend on what size flake you use

 

Depends on the product... viscosity..., temperatures..., humidity... and your equipment.

Shoot test panel until you get the results you want.

After experimenting with the above variables I never used a gauge as well... really just sprayed a test panel until I got the flow I wanted.

Now I use the HVLP system and only fiddle with the flow of the paint at one set air volume.

 

when i was running waterjet i was spraying at 55k psi.... it seemed to cut good.....

 

i sprayed some primer yesterday at 100psi, dumb ass me forgot to adjust the pressure after running air tools however i got the best results i've ever had???? why the hell would that happen? i am just using an el-cheapo spray gun (i mean like the cheapest i could find) maybe that has something to do with it? or was it just luck?

 

Never painted before and your starting with a flake job !!! Best get some practice in then.

Do yourself a favour and lose the Flake buster if its a car your doing. I was given one to try and i reckon they are crap for a big job like a car, better suited to small bike bits although i still don't like them.

I painted the 32 below with a Mini flake, 3 flake coats, then 3 clear, then 3 more clear, then flatted & polished. You will need more clear for the bigger flake.

 

as others have said it all depends on the paint,and gun.with the old style guns i used 30-55 psi.i have also sprayed cars at 2psi.i have two old hvlp turbines.they use a 1'' hose.i sprayed my last car at 6psi.i flaked it,put some .050 crushed glass in it,andcleared it with the same tip.it came out great imo.

 

I usually adjust by ear...but the pressure guage is usually around 3o/35 ish on a regular old style binks/devlbiss gun. I use a metal paint paddle to mix the paint and sort of eyeball the run off....built in Zahn cup sort of??

 

you guys are going to be in a world of hurt when everybody switches to waterbase, so many variables to make it right.

 

heard that when they came out with acrylic enamel, polyurethane, base coat, and urethane. we will adapt.

 

What does HVLP stand for??

 

All,

High Volumn Low Pressure !

Good Luck,
Sonny

 

For those using water based paint: Are you using it because of EPA mandates, or do you actually like the stuff?

 

37-40

 

X2...

Get your basecoat to cover, then a quick mist coat to even it out.

Use a paint paddle first. It takes a little longer, but it will make the final result what you want not what you got.

 

In Calif all legal shops use waterbase basecoats it works. All of the production Painters I know actually like it.

 

Thanks Sonny!!

 

I bought a new Ford truck in 1988 and literature with it stated that if the paint failed they would paint it one more time at no cost. Obviously they were having problems with new EPA compliant paints at that time. Were these water based and are they the same as used today? In other words, does water based hold up as well as other paints?

 

High pressure 40 - 50psi

HVLP 15 - 20psi

I set the pressure at the gun with a cheater valve, then spray a pattern and adjust up / down till it looks right.

 

high volume low pressure

 

high volume low pressure