Posted 2005-06-23 3:37 PM (#26982) Subject: air spray paint question
Veteran
Posts: 140 Location: Colorado
Hi, if runs and drips occur, is it due to too much thinner? My red oxide coats came out pretty good, my first white coat came out good for one wall, and kinda drippy for the other side of the wall (after refilling the gun). I have to let it dry 24 hrs between coats. Can I sand down my drips tomorrow before the next coat so they look smoother? This is an industrial oil based enamel specifically for metal (dented can from Home Depot - $5 :-) - yeah baby!)
Posted 2005-06-23 5:54 PM (#26989 - in reply to #26982) Subject: RE: air spray paint question
Expert
Posts: 1989 Location: South Central OK
I had a K5 Blazer repainted once back when clear coating was still a new art form and the clear coat was runny. They sanded (you'd be color sanding) and reapplied a much thinner coat.
Truck was lacquered solid by the time they were done with it and it shined better than new!
I'm not technically gifted in the area of paint, so I can't directly speak to the question.
Posted 2005-06-23 7:14 PM (#26994 - in reply to #26989) Subject: RE: trailer axles
Member
Posts: 22
Location: Webster, NH
Could be that the paint was too thin. Could be that you put the paint on too thick. Could be how second coat was bonding to first coat. Could be wrong air pressure. The problems with spraying are many and unless you're watching someone put it on, it can be very difficult to tell what the problem is. The first two problems are the most common.What you want is a bunch of thin coats, usually four or five to do the job right. They should go on very thin and not running as they are sprayed. If the drips are thin on paint, then probably your mixture has too much thinner. If the drips are thick, then you are probably putting too much paint on. This is an art, not a science, and even experts can have problems. On the bright side, it all sands off and you just start over.Jim Clark-Dawe
Posted 2005-06-23 9:51 PM (#27009 - in reply to #26982) Subject: RE: air spray paint question
Expert
Posts: 2689
My first guess is TOO MUCH PAINT !
It may sound crazy, but don't try to cover it in one coat.
You need to see someone do it, but when it is just right you can see the primer through the first coat while it is still wet, but not once it is dry.
Paint that is applied too thick will chip off very easily, it may even fall off if the other side of the metal is bumped hard enough, though not hard enough to leave a dent.
Posted 2005-06-23 11:12 PM (#27014 - in reply to #27009) Subject: RE: air spray paint question
Veteran
Posts: 140 Location: Colorado
Ok, thanks! This all makes sense. The drips are thin, meaning not raised up. I thought at first they were lumpy, but they are not. So it definitely looks like too much thinner coupled with too much spray in one spot... Also I re-read the can and I was supposed to use Acetone for thinning that stuff, not paint thinner (mineral spirits based). DOHT! It did flash off and dry looking great.
I also have been using the unscientific method of splashing in some thinner (about 10%), I will start measuring. I think doing scrupulous prep work got me this far, now I'm winging it on the painting and I have to buckle down and do a better job of it...
This part is fun. I dreaded cleaning the gun and handling the paint, but it's turning out to be interesting and challenging. Cleaning the gun is simple, easier than cleaning a brush (for me, anyway). Love my ventilator. :-) Yahoo!
Posted 2005-06-24 12:44 AM (#27019 - in reply to #26982) Subject: RE: air spray paint question
Expert
Posts: 1989 Location: South Central OK
Another problem with thick paint is that it won't cure properly and that leads to paint peel in the future. I hope your incorrect mix of paint thinner won't harm the paint layer. I'm flashing back to all those 80's Chevy's with those cool drive and peel paint jobs, remember those...the reason mine got repainted!
Posted 2005-06-24 8:41 AM (#27027 - in reply to #27019) Subject: RE: air spray paint question
Veteran
Posts: 140 Location: Colorado
I hope it doesn't peel. :-( It looks good so far - no orange peel, bubbles, or anything other than those thin drippy runs. It looks like those will be fine to just paint over this morning...
I should have sanded the sheets off as part of the prep (I just degreased and metal prepped). There are a few little metal bits stuck on them from welding that now make it look not quite perfect. I didn't notice them until it was painted white.
Posted 2005-06-24 11:20 AM (#27037 - in reply to #27027) Subject: RE: air spray paint question
Expert
Posts: 2953 Location: North Carolina
From your pictures... looks like your spray technique needs some help.
Try moving the gun side to side. press the trigger only AFTER you start to sweep and release BEFORE stopping the sweep. This technique will avoid the runs at the start and end of your spray sweep.
Posted 2005-06-24 12:53 PM (#27046 - in reply to #27037) Subject: RE: air spray paint question
Veteran
Posts: 140 Location: Colorado
Hah, that's putting it mildly. :-)
A lot of the problems happen in the corners, where (1) I can't nearly as well (2) the gun is a lot harder to handle in the corners.
It has the 2nd coat on now and looks much better... Using a measured amount of acetone as thinner made the paint/spray a lot more consistent, and I turned down the spray volume... More pictures later!
Posted 2005-06-24 2:01 PM (#27050 - in reply to #26982) Subject: RE: air spray paint question
Expert
Posts: 1989 Location: South Central OK
Not to say your wrong hoss, but I've always heard you should have constant trigger pull while sweeping into the line. Turn your wrist from 90 to the wall and then turn your wrist 90 away at the end, then move down while pointed away from the wall and sweep again in reverse. Never letting off the paint trigger, the stop and start of paint in the gun can cause runs.
Posted 2005-06-24 2:56 PM (#27058 - in reply to #27050) Subject: RE: air spray paint question
Expert
Posts: 2953 Location: North Carolina
Originally written by huntseat on 2005-06-24 3:01 AM
Not to say your wrong hoss, but I've always heard you should have constant trigger pull while sweeping into the line. Turn your wrist from 90 to the wall and then turn your wrist 90 away at the end, then move down while pointed away from the wall and sweep again in reverse. Never letting off the paint trigger, the stop and start of paint in the gun can cause runs.
Huntseat ... I appreciate your point... This seems to be a pure case of "different strokes for different folks" LOL I always had the runs at the start & stops before I watched someone else paint a car.
Posted 2005-06-24 4:55 PM (#27065 - in reply to #26982) Subject: RE: air spray paint question
Veteran
Posts: 140 Location: Colorado
Photos of the second coat. There's some glare in the picture, but the coat is greatly evened out. I fiddled quite a bit with the sprayer settings... Found some paint goggles at Sherwin Williams that have a peel off front, so hopefully I'll be able to see what I'm doing.
Posted 2005-06-25 7:39 AM (#27077 - in reply to #26982) Subject: RE: air spray paint question
Extreme Veteran
Posts: 402 Location: Lockport, Illinois
Looking at the pictures, I could tell that the pattern on the gun is too narrow. Take a piece of cardboard and use it to try out your guns pattern before you spray on the trailer. You should take horizontal sweeps that overlap approximately 3" to 4". For the corners, you can turn the nozzle on the gun 90 degrees so the material comes out vertical. You want to start your sweep before you come to the part you want to paint, also before you come to the part you want to paint squeeze the trigger. Continue with the sweep after you finish painting the part, and then you could release the trigger.
As there are many conditions that effect the final coat, I would invest five dollars in a book on painting with a paint gun. Even the pros don't get a perfect job everytime.
Posted 2005-06-25 9:11 AM (#27081 - in reply to #27077) Subject: RE: air spray paint question
Veteran
Posts: 140 Location: Colorado
Thanks BigT, that's exactly what I thought but I can't figure out how to adjust that part of the spray pattern. I can get more or less air, and can get more or less paint with the air, can turn the pattern 90 deg. I'll see if I can find a book. This is kind of a small town... Not sure if I will be able to find one on hand.
Posted 2005-06-25 9:33 AM (#27084 - in reply to #26982) Subject: RE: air spray paint question
Extreme Veteran
Posts: 402 Location: Lockport, Illinois
There are normally two adjustment screw on the back of the handle of the gun, one is for material flow, and the other is for pattern. I would put something inexpensive in the sprayer (paint thinner) and experiment with the adjustment of the two screws. While adjusting the pattern screw, you can see the difference in the shape of the spray coming from the tip. If you just loosen the retaining ring around the tip, you can rotate it. This information is for the old type of air paint gun. not the HFLP new type. Do you have a compressed air paint gun, or a electric one, either way instructions should of come in the box, if not look up the manufacture on google and ask for instructions.
Posted 2005-06-25 9:48 AM (#27086 - in reply to #27084) Subject: RE: air spray paint question
Veteran
Posts: 140 Location: Colorado
Thanks BigT. The gun I bought is a gravity feed and it's attached to a portable air compressor. I looked up online and found a couple of very specific articles about tuning the gun up to get the perfect spray pattern, I will try that before I shoot another coat today.
One of the tune up articles made me feel a little better, it said if you never have any drips, you aren't trying hard enough. :-)
air spray paint question
