Paint gun pressures

[NHCharger]

I'm getting conflicting advice on paint gun pressures. I'm getting ready to paint my car. reading the data sheets for the paint and clear both say 8-10 pounds at cap for HVLP guns. the jobber that I'm buying the paint from use to be a painter and he's telling me to run 18-20 pounds.

[A383Wing]

I say go with the painter advice....with not enough pressure, you may get clogging or clumps

my 

Bryan

[jaak]

When the jobber tells you 18-20 psi, he referring to inlet pressure. Its what your gauge at the gun inlet will read with trigger pulled. I like to set the pressure at what the gun manufacturer recommends (at inlet, mine recommends 22-24 PSI, IIRC), then tweak if neccesary.

Jason

[NHCharger]

I'm worried about wasting material and over atomization.
If sprayed on with too much pressure will the paint/clear lay down properly?

[garner7555]

Spraying with air pressure too low is more of a problem with getting it to lay down.  If your pressure is too low you will have a very "orange peal" finish.

[Dino]

Don't be to set on the numbers as they vary wildly with different equipment.  You need to do this by feel.  Give the inlet near the max air it can handle, should say what it is in the manual.  Get some thinner in the gun, so as not to waste paint, and press the trigger so only air comes out.  You're looking for a steady pressure but not so much that the gun recoils.  Get a piece of old metal and depress the trigger completely to spray the thinner on.  Watch how wet it goes on.  If it's hard to lay down a wet coat then add air, if the wet coat is pushed away, you have too much air.  There is a fairly wide range regarding air pressure and it depends on what kind of paint you're using as well.  Are you doing base/clear?  If so, base is extremely forgiving and by painting the base you will know what pressure works best for you.  When it's time to clear you'll know what to do.

Alternatively, take your paint gun to a good painter and have him show you what range you need to be in.

[NHCharger]

Alternatively, take your paint gun to a good painter and have him show you what range you need to be in.

Unfortunately it's because of my good painter that I'm asking this question. I have the car ready for paint. My painter was supposed to paint it this Saturday in my shop. I'm taking Thursday/Friday off to prep the car. Now he can't make it and I can not take the next Thursday/Friday off so I said F*ck it, I've done everything else myself, might as well do the finish paint.
I painted the engine bay last night, ran about 18 pounds of air. Paint laid down nice. Just wanted some additional input from the painters here before I tackle the entire car.

[Dino]

Alternatively, take your paint gun to a good painter and have him show you what range you need to be in.

Unfortunately it's because of my good painter that I'm asking this question. I have the car ready for paint. My painter was supposed to paint it this Saturday in my shop. I'm taking Thursday/Friday off to prep the car. Now he can't make it and I can not take the next Thursday/Friday off so I said F*ck it, I've done everything else myself, might as well do the finish paint.
I painted the engine bay last night, ran about 18 pounds of air. Paint laid down nice. Just wanted some additional input from the painters here before I tackle the entire car.

Sounds like you're doing just fine.  Remember, paint is workable so if something does go wrong, there's usually a not too hard fix for it.  If you get a run, keep going.  It can be removed later.  As long as you lay down good coats and the final two are nice and wet you will be absolutely fine.  If you feel that it doesn't look even everywhere then you can wet sand and polish to make it shine like a mirror.  However if you lay it too thin it'll look coarse and you'll sand right through it before you get the polisher out.  Too much paint can be fixed, too little means you're starting over.

Now, what kind of paint are you using and how is the 'paintbooth' set up.  Do you have enough forced ventilation to get the fumes out?  This is especially important when painting clear as it'll recreate Stephn King's 'The Fog' and that damn fog will ruin your fresh coat of paint when it falls back into it.

[NHCharger]

Paint is PPG Deltron 2000 base.
Clear is Dupont G2-4700s (I think). This was the paint my painter was going to use.

I have a paint booth set up in my shop made of plastic sheeting. I'm going to re-build it before I paint the entire car. Booth is approx.15'x40'. Car is completely disassembled so it takes up some room. I have three vents cut in the plastic about 7' off the floor with air filters taped over them. On the opposite side I have a large commercial fan mounted in a window. I built a plywood box around it down to the floor and have an 8"x24" opening at the bottom. With the fan running it will pull the exterior door of the shop open if I don't have it latched.

[Dino]

Paint is PPG Deltron 2000 base.
Clear is Dupont G2-4700s (I think). This was the paint my painter was going to use.

I have a paint booth set up in my shop made of plastic sheeting. I'm going to re-build it before I paint the entire car. Booth is approx.15'x40'. Car is completely disassembled so it takes up some room. I have three vents cut in the plastic about 7' off the floor with air filters taped over them. On the opposite side I have a large commercial fan mounted in a window. I built a plywood box around it down to the floor and have an 8"x24" opening at the bottom. With the fan running it will pull the exterior door of the shop open if I don't have it latched.

You'll be fine.   

Don't forget a white painters coverall and a good active filter mask.  We'd like you to stick around with us living folk for a while.

[NHCharger]

Don't forget a white painters coverall and a good active filter mask.  We'd like you to stick around with us living folk for a while.

So your saying my blue paper shop towel filter will not work

[Dino]

Don't forget a white painters coverall and a good active filter mask.  We'd like you to stick around with us living folk for a while.

So your saying my blue paper shop towel filter will not work

[69finder]

Sweet mask, I don't think it's NIOSH approved though

Too high of pressure will lead to 'orange' peel as well.  I used to run about 60 PSI because my crap gun used to make a sweet pattern, but now I have a decent gun, it works perfectly at 25 PSI (I like a little higher than a little lower as the compressor kicks in, or line loss, reg loss etc).

[cdr]

pics of car or it didn't happen 

[NHCharger]

some crappy iphone pics

[cdr]

OK now i believe you    you are way ahead of me lookin very good !!!!! 

[cdr]

i like before & after pics 

[Highbanked Hauler]

   Love the color there Brian

[NHCharger]

Thanks Al. Some day when I get a few minutes I'll update my build thread. Right now my wife is on a paint all the rooms in the house kick. So the car has sat while I work on the house.

[Silver R/T]

Usually you will run bit more pressure for clear coat to atomize it properly.
I would get a 3M dual cartridge respirator, SAS goggles, once fumes start getting into your eyes you will not be able to see well and it will burn your eyes to a point where you'd have to stop, you wont be able to see what you're panting as well.

[beedees]

Thanks Al. Some day when I get a few minutes I'll update my build thread. Right now my wife is on a paint all the rooms in the house kick. So the car has sat while I work on the house.

Make such a mess/bad job in the first room so your wife will run you out of the house and do it herself. Hey, it worked for me!

[NHCharger]

Thanks Al. Some day when I get a few minutes I'll update my build thread. Right now my wife is on a paint all the rooms in the house kick. So the car has sat while I work on the house.

Make such a mess/bad job in the first room so your wife will run you out of the house and do it herself. Hey, it worked for me!

Unfortunately I'm a contractor, built houses for 20 years. Did all the interior paint so I have no excuse. But I like your ingenuity