I posted a while back about problems with fish eyes in my paint. The consensus is that it was contamination. I have cleaned out my air hose with lacquer thinner, cleaned the air passages in the gun, have a descant filter in the line, used fish eye eliminator, wipe down the part with a degreaser using a new blue paper shop towel. I'm getting these small imperfections in the paint. They are smaller than a pin head. I'm using single stage Acrylic Polyurethane. The imperfections seems to be on horizontal surfaces and not on vertical surfaces. Is there something that can cause this that is not related to contamination? Too high pressure at the gun? Gun too close to the surface? Not waiting enough time between coats? Your comments are appreciated.
Just for kicks set your gun up like you do when you paint. don't put any paint in the cup. Take a clean piece of glass or window and act like your painting it. See if anything comes out of your gun. For what it's worth I do a final wipe down with spray away glass cleaner and blue paper towel just before painting. Then I will use only half trigger, so it's just air, to blow the parts off.
I just sprayed the tailgate on my OT pickup. Looked a lot like that. I forgot to drain/clean the water separator on my compressor before starting. Not a good system, but it works when I do my part.
What exactly are you using to clean the surface before spraying? Many degreasers are not compatible with painting chemicals. What do the manufacturer instructions say about time between coats? Are you using reducer? If so, is it the exact reducer that the manufacturer names, and in the correct ratio? Is it the correct temperature range for the conditions? What gun are you using? What is the tip size? Are you spraying heavy coats? What it the gun pressure regulator set to, when the trigger is pulled? Do you have an oil trap on the supply line? How often do you drain the compressor tank, and is there oil in what comes out? This does very much resemble solvent popping, but other things need to be ruled out.
Had something similar shooting clear and it was the tack cloth. I read later your supposed to take them out of the package and let them air out? I agree it looks a lot like solvent pop. I would get a new hose instead of cleaning an old one with lacquer thinner. Your coat looks pretty thick.
If you are getting rusty water every time you drain the tank, you need to replace your compressor soon. Compressor tank rupture can be nearly as violent as an explosion. Consider a timed auto drain. Mine kick off for 15 seconds, every 15-minutes. Use the correct amount of reducer. If you use too much, it will cause solvent pop. Spray lighter costs. The thicker the coat, the harder it is for the solvent to flash off, and the longer it will take.
Yellow circles are fisheyes The white circle area is orange peel Grey arrows looks like a prep issue. The prep issue is the easiest. Needs sanded better The orange peel can be improper reduction, gun movement/distance air pressure or combinations of all those. The fisheyes. Need to know exactly what prep cleaner you are using
How much fisheye eliminator is being used? I’m not a fan of cleaning an air hose. A new one should be used. Just using the same hose to paint that you use oiled air tools can cause an issue. No silicone products in the painting area. The presence of a fisheye eliminator on a previous repair can cause an issue according to some internet experts. I haven’t used fisheye eliminator in decades so I don’t know.
I'm leaning towards something on the surface causing the fisheye. Did you do a good wax and grease cleaning before sanding, not just afterwards before spraying? I've run into that before. You really need to clean the surface well before sanding, or you will grind the wax, or whatever else is on the paint into the sanded surface.
I like to use 2 cleaners. An alcohol based or ammonia cleaner. Some use glass cleaner with ammonia. There are commercial alcohol cleaners but I’ve cut denatured alcohol 50/50 with water. Some used isopropyl alcohol. Then a pre-paint cleaner. Some will evaporate faster than others. Some are “hotter” than others. Meaning they can soften paint. I put cleaners in a squirt bottle, and wipe off while wet with a clean rag. One panel at a time. Never allow the cleaner to dry.
Some of it looks like solvent popping. I see you're from Florida with high humidity and heat. Solvent popping is when the hardner and/or the reducer need to be slower evaporating/curing. The paint film is trying to skin over before the solvent can evaporate out. The result is small pinholes. Some of the "holes" could be small fisheyes, also as Anthony mentioned.
how about....contamination falling from above? It would settle on the horizontal surfaces, not the vertical surfaces There are so many things that can cause problems, and we can't see your shop, so we can just offer all these guesses. Good luck...
Being that they are only on horizontal surfaces, it could be solvent popping. Do you have any kind of fan circulating the air. If not, wait longer between coats and put lighter coats on. Also, after I have cleaned the surface the FIRST time, I never put anything but water on the primer when I am wet sanding. I have had degreasers cause that kind of fisheye before.
I don’t shoot a lot of single stage. Don’t think it’s ever solvent popped. But those could be that the more I think about it. The solvent pop I see looks like smaller dots.(Base clear) and a lot of em the couple times it happened. Lots of tiny dots. I guess we need to know more info. Paint brand, mix ratio, how long you let it flash (time between coats) gun used/tip size. Reducer and hardener temp. Temp when sprayed. That texture looks heavy. Applying too thick of a coat.
How long did the primer dry before you painted with color? Have you used silicone anything in your shop in the last 6 months? Fisheye eliminator masks a problem. When we used it back in the 70's, in 3 months the shine would fallback and need to be buffed to shine again.
Your compressor heats the air when it compresses it, so if you lay the hose on a cold floor it will condense the water in the air in the hose, and it goes on the car. Also if the pump has worn rings you can get oil in the air. Air used in a body shop has its science !!!
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