Thread: I'm about to give up . . .

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. . . . trying to clearcoat this dang body. I did the frame just fine. No problem. Everything flowed out, and the clearcoat went on smooth enough that I didn't have to do any buffing. Most of it is hidden by the channelled body, anyhow. However, the hood, trunk and doors are another issue.

I've got a good gun (Binks M1-G with the right air cap. I have a good, dry air supply, with an oil/water trap, a small dessicant water filter, a very large dessicant water filter, and a water ball at the gun. I'm using the right proportions of everything, and the reducer and hardener are tuned to the temperature.

I just can't get the clear to lay down. Some spots are orange peeled, some spots look severly orange peeled, some look like dry spray. I set the fan to about 10" with a nice pattern, and then tune the fluid feed for decent coverage on masking paper taped to the wall. It just has to be my spray technique, and I don't know how to fix it.

This is NOT my first car, by a long shot, and I've never had this kind of problem before.

I'm thinking about taking the body and the doors, hood and trunk up to the body shop on the corner and say "clear this POS."

I'm not necessarily looking for advice - just venting . . .

[QUOTE=Henry RifleI'm not necessarily looking for advice - just venting . . .[/QUOTE]

Seems to be a lot of that going around!

Could it be static charge in the glass?

Yeah, I've grounded the parts, but I've done glass both grounded and ungrounded. Grounding a non-conductor never made a lot of sense to me, but I keep doing it.

I'm pretty sure I'm not getting enough atomization of the paint. I'm going to kick up the reducer a bit. I'm also going to get something to practice on before I do anything else. I guess I'll do some sanding on the parts I already have and see if I can get them to looking right.

This is how I've been tuning my gun:

Set the fan width as needed (you don't want to change it after you have "tuned" the gun). Turn out the material knob about 2 1/2 turns.

Set the air pressure at the inlet to the gun to the manufacturer's specs. On an HVLP gun, this spec is usually found on the gun, and is the maximum PSI it can have while still maintaining the maximum 10 lb at the cap for legal HVLP transfer efficiency (68 %). You are now ready to do a test sprayout.

Tape a piece of masking paper on the wall for the test. Hold the gun at a right angle to the wall, just as if you were going to paint the wall. Hold the gun at a spread out hands distance (about 8 inches, or 22 centimeters). Pull the trigger to completely open for a split second and then close it. You want an ON-OFF wide open-completely closed in ONE movement. You should have a cigar shaped pattern with complete coverage in the center with fading coverage going away from the full coverage cigar shape in the center. The center should be fully covered without any runs. If you have runs, either you are holding the trigger too long, you are too close, or the gun is simply applying too much material; in which case you need to screw in the material knob or turn the air pressure down. But most likely if you have turned the material knob out the 2 1?2 turns and the air is set at the factory specs, you are just too close or holding the trigger open too long.

The droplets you see trailing off the center are what you will use to "tune" your gun.

Turn in the material knob to make the droplets smaller (and or raise the air pressure). The balance you need to attain is the smallest droplet size possible before you lose the coverage desired. In other words, if you turn in the material knob too far, not enough material will be coming out to cover the panel!

Now, you'll notice that I said, "raise the pressure to the gun", while earlier I said to set it to manufacturers specs. We are talking a very small adjustment. It is a fine balance in material-to-air ratio and a little more air than specified is okay. Even if it is an HVLP gun the inlet pressure recommended is to maintain the 10 lb limit at the cap. Well, about three quarters of the country has no regulations for HVLP use, so if you go over the 10 lbs all it will do is atomize the material a little better. You may lose a little of the benefits of HVLP though. But remember you have a lot of control with the material adjustment knob.

After you are happy with the droplet size, DON'T TOUCH THE FAN CONTROL. It will change the PSI at the cap and will change the atomization you worked hard to get.

Do this sprayout every time you spray as material change, temp, and humidity will necessitate a sprayout droplet pattern test. Good luck!

I also found this interesting:

QUESTION: I have tried twice to paint a car with a primer, base and clear-coat system. the primer went on fine. the base coat went on a little rough like it was drying before it was hitting the surface. the first attempt at clear coat yielded too many runs. I started over from scratch, and again at the clear coat stage i first applied a tack coat then waited for 15 minutes for it to flash. I applied the clear-coat wet as possible it seemed to going on like it was splattering instead of a fine mist. I was using an HVLP gun with a 1.3 mil nozzle and about 13 psi at the gun. I have to redo it again as the car has 90% orange peel.

Answer: Crank the pressure up on that gun so that you have about 50 psi going into it. Higher if you want. the manufacturers give specs that meet environmental regulations for low over-spray, but aren't practical in real life.

Here's my take on the whole set of manufacturers' recommendations: The amount of thinner/reducer they recommend has more to do with keeping the Feds happy than it does with the quality of the paint job. I learned that when spraying the sealer. Kicked the reducer up about 25% and got a better job. I should have done the same thing with the base coat. Same thing on the pressure reccomendation for the HVLP gun. 10 PSI meets the Fed's rules. More probably does a better job. You can visit me at Leavenworth, but I'm going to get a decent paint job somehow.

pull the fan in a bit and use a slower thinner you may be getting fall back in the paint from not moving out the over spray or paint is dryng to fast for a good melt in on your over laps

Originally Posted by pat mccarthy

pull the fan in a bit and use a slower thinner you may be getting fall back in the paint from not moving out the over spray or paint is dryng to fast for a good melt in on your over laps

Bingo. I would try a slower thinner.

Same as sand blasting, it builds up a electrical charge by induction.

Which is why we ground a helo before anyone touches it . . .

henry rifle do not give up you will get it. i did this for aliving and painted about one car a week and some some touch ups to. then go home and paint planes and cars at my shop a hang out at my friends a paint stuff at there to. never painted much in a real booth but a lot of home made stuff and it all boils down to air speed to move out and over spray it would hang up and alot of time drop back down this would make for dry spots the roof hood and deck i would start from the farthest panel and work to the draw this would be the ex fan sometimes i would thin out the last coat but it is much better to leave the last coat open longer this helps so thinner do not get trap down and helps with lay down but dirt may get in a lot of time i would lay the second coat out wet and let it set up good to let the booth clean out then loosen up the last coat a bit or go slower on the thinner if i had some and put it on wet and slow it would at times not lay out supper flat but i sanded and wheeled out most of them any ways

Thanks, Pat.

I'm going to cut and buff also. My only concern is that a '34 has a lot of rounded body trim. Getting the orange peel out of that area is going to be a bear.

Fortunately, the only place I have it now is on the doors. (I attached the photo of the body for illustration only.) The hood and trunk don't have very much. I won't let it happen on the body.

Bottom line, I'm going to a slower reducer and more practice before I shoot the body.

i help with the holley car and them spots there were hand rub. the way a round that is put it down get some build cut it back with 1000 grit and put two more coats i would say to try back off them abit so you will not get to much build in them spots if it get to heavy you will have alot more work

alot now is hardener to even with slow thinner it kicks off to fast if you have the wrong hardener i was told by a guy he would not use 1160or1170 for dbu ppg he use nolead gasif it got hot i do not know if he use race fuel or diesel to thin it

Here's how I got in trouble: I started out with the trunk lid, and it did pretty well, so I thought I had it down. Too cocky, I guess. However, after I did the hood and doors, everything pretty much went south.

I'm using Sherwin Williams products. The temp range for the hardener (UH-70) is 70 - 100F. The temp range for the reducer (US-4) is 75 - 95F. I use my exhaust fans to draw air-conditioned make-up air from my house into the garage, and the house runs about 73 - 78F. I run the A/C in my garage for a couple of hours before I start painting. The temp sure won't hold stable at that temp because of the amount of air I'm exhausting, but it stays well below outside temp.

I didn't have a thermometer in the garage, but I'm guessing the temp was a little over 80F. It certainly wasn't anywhere near our high today of 90F. My products are right in the middle of the temp range for my conditions. However, I may pick up a slower reducer (US-5 , 80 - 100F)on Monday.

I'm pretty sure I just haven't gotten the mixture/pressue settings where they should be. That's my main problem. I also need to over-ride the feds and play with the pressure and the reducer ratio.

Now, I need to find something to practice on - other than the car . ..

Originally Posted by Henry Rifle

Now, I need to find something to practice on - other than the car . ..

Gotta cat?

No, but I'm going to rename my garage "Toad Manor." I've evicted 7 of them in the last week. While working on my car, I've had the water hose coming in under the garage door. That leaves a little gap for them to squeea through. I have no idea why they like my garage.

They're too lumpy to practice on anyhow. They're already have a pre-orange peeled skin.

Originally Posted by Henry Rifle

I have no idea why they like my garage.

My guess would be the kinship with Kyle!!

Rather than paint the body today, I decided to try cutting and buffing the trunk lid. I took a looooooooooong time - in fact, that's all I got done. I was being extra careful since it had been a while since my last cut and buff job, and there was quite a bit of orange peel to sand off. I started sanding the trunk lid side-to-side with 1000 to get rid of the dirt flecks and orange peel, then I cross-sanded front to back with 2000 grit. I buffed with Mequiars 84 Compound, then 83 Dual Action Cleaner/Polish, then 82 Swirl-Free Polish, and finished up with hand glaze. A lot of work, but at least I have ONE finished part.