Painting with HVLP Spray Gun, and Auto Paint

Hi Guys!
I just started painting with the Harbor Freight HVLP Spray Gun. I have it set so when I pull the trigger the pressure guage right at the spray gun reads 20 PSI. It seems the paint comes out of the gun in a much courser spray than it does with my old Binks Siphon Spray Gun. Is this normal in your experience with using this gun? What kind of pressure do you guys spray at with this gun?
I am planning on using Omni brand base coat and clear coat. The sales person at the automotive paint store where I purchased the base coat said masking tape would pull up the base coat. For those of you using automotive base coat, have you been able to use regular masking tape or fine line tape to tape for your trim colors? Have you had trouble with the tape pulling up your base color?
This is my first crack at using this automotive paint so any advice from you more experienced guys would be appreciated.

Jim, I too had the experence of having it look like it was going on coarse, but as it flowed out that was pretty much gone.. Some of the more versed painters can jump in and answer better.. As for masking tape I have been using "Fine Line" by 3M and haven't had a problem with it pulling up.. You might try it on a test piece first and use low tack tape of some kind..
Gil:+

>Hi Guys!
>I just started painting with the Harbor Freight HVLP Spray
>Gun. I have it set so when I pull the trigger the pressure
>guage right at the spray gun reads 20 PSI.

With the trigger depressed, the pressure shoud be at a max of 10 psi (wide open). 5 to 7 PSI is about normal. 20 is way to high.

There is a thread where I explained in detail how to set the gun.

>>I am planning on using Omni brand base coat and clear coat.
>The sales person at the automotive paint store where I
>purchased the base coat said masking tape would pull up the
>base coat.

Oh my Goodness, it will? Wo Hooo. The guy at the paint store is a friggin' genius, and we must have been doing things all wrong!

GZ STANDING ORDER: THE GUYS AT THE PAINT STORE KNOW LITTLE IF NOTHING ABOUT PAINTING, IF THEY DID THEY WOULD BE PAINTING FOR A LIVING.

What he said is simply FALSE.

Yep..the guy is misinformed or just doesnt know.

I have carefully used the 3m blue fine line without trouble. But i go around first with the paper sensitive tape (really low tack, about an eith to a 1/4" away from the line so the full width of the blue isnt on the paint--perhaps un-necessary, but I havent had any problem.

I guess my experience with the HF gun is different than Brads on the pressure required. I sprayed primer and the color base at 15-18, trigger down, at the inlet guage.

For the clear, I needed to use about 40 inlet--according to the way these gusns function with the internal regulator, these settings will result in approx 10 at the nozzle.

Have you adjusted the air control at the bottom of the handle? It's function is not well explained in the instructions but it is the internal regulator/flow control.

As long as the material is (thinned, and fed at the right rate, and the fan is appropriate, the paint lays down fine at 10-15 PSI. But I found it impossible to get the omni clear to atomize well at less than 40 inlet.

I'm going to be testing the Matrix clear in the next week or so to see if it is significantly different than the Omni clear.

Just my experiences, Brad is way more experienced with this material than I but not sure he has used the Omni yet.

We have discussed the pressure differences without a good discovery of the reasons--so just try it at the higher setting. The gun reduces or converts the incoming air to HVLP. My guage was marked with a green zone at around 40 in fact.

FWIW

You wouldn't believe the discussion I got into at the paint store when I told the manager I planned to use reducer in the clearcoat! She thought I was crazy, and that I would ruin the properties of the clearcoat. GZ, I even took your article with me.

Have to say, I did have some problems with paint pulling up with my last plane. I used 3M fine line tape and had some problems with this. All on the bottom. I suspect that I pulled the tape too soon. With dope, I always pulled the tape while the dope was still wet. My experiments with this last plane seem to indicate that I should wait until it's mostly dry before pulling tape. I shot the thing upside down first then right side up then pulled the tape. I suppose the bottom had just enough time to soften the layers below. No problem with the low tack masking tape I use (the auto paint store stuff).

The guys at the paint shop I buy from are pretty knowledgeable. But then, it's not a commercial shop as such. They sell pretty much only to custom painters and custom shops. They only sell to the collision on occasion. They have a custom paint shop in the back. Pretty cool guys generally.

I have the large Harbor Freight gun that I use for primer coat. I use a Binks HVLP gun for the color and clear. And much as Brad says, I shoot it at about 8-10lbs at the gun with trigger depressed. Works fine, but has a very fine spray.

I simple way to keep pull ups from happening is to pull tape with a hairdryer. I do it every time now no matter what! I simply heat the tape or stincel with a hair dryer NOT A HEAT GUN for just a moment. It releases the adhesive and it just rolls right off and there is hardly ever any residue. Tne I move along ahead of where I am pulling with the hair dryer and it comes off very easy. Dont over heat it.

As far as masking tape goes, use the 3M green masking tape. It works great!

Reducer. If it ruins it then why do they sell it? Anyway the paint guys really very rarely know what we are doing. I finally took my plane into the store and showed the guy what I was doing. From there he really had a good grasp on what we are doing. He has always had good ideas and has been more than helpful. Before I took the plane in he really couldbt help me much because he juts didnt know what I was up against.

LAST EDITED ON May-24-04 AT 06:03 AM (CDT)
 
Doug,
I understand that the hair dryer softens the adhesive and prevents pulling up the previous layer. Do you let the coat just sprayed dry or is it still tacky when you use the hair dryer?

LAST EDITED ON May-24-04 AT 03:08 PM (CDT)
 
I usually let it dry. About as long as it takes to clean out the gun and get the next stuff ready, maybe 15-20 minutes. It doesnt take long. I wouldnt pull the tape with coal still tacky. Getting near it at that point is a no no for me. I could really mess things up. I stay away until it is dry.

Hi Randy:

On the tape, I ususally hit the edge with some 600 paper ONLY on the tape edge to break the edge, then pull the tape--so the tape doesn't have to tear the paint edge.

Is that the Binks Mach 1 conversion HVLP you use at 10 PSI inlet?