This is one of the defects I ended up with on my first attempt at spraying paint.

I am assuming it is a result of contaminants in the air, either water or oil.

DSC_1398 by Larry Madsen, on Flickr

There are maybe a dozen or more of these *tiny craters* almost all on one side of the car.

Seemingly they occurred all in a short period of spaying and maybe even on just a single coat ... I admit I'm guessing a bit on that theory. To go along with that though, I did use a longer hose to spray my paint. It's a hose I use for general purpose air and that hose had been hooked up to an unfiltered tank access valve. I could have had some oil in that hose before I started and it nailed me right out of the chute.

I'll be getting a dedicated longer hose for painting in the future just to be sure that old hose is not going to have any chance at screwing me up in the future.

I have no intention of sanding the car back down to re-paint. I'll live with them on this project for now, but I do need to determine what to do so I don't keep getting this result.

I am running two moisture traps on the line.

I am aware of the filter linked below. They used one like this at a shop I hung around in the past. Would this be a good extra trap for the air line?
https://www.amazon.com/Motor-Guard-M-60 ... pd_cp_hi_1

Next question would be ... Could these craters be touched up? Keeping in mind these are mostly no larger than a pin head.

It seem maybe anything on the flat horizontal surface might allow me to rough up the crater and put in a drop of my acrylic enamel to fill it back in. Good idea? ... Bad idea? As I stated above I can live with it as is, but if it would be easy to make an improvement without high risk of making it worse that could be good as well.

Well, 40 views.

Anyone with knowledgeable comment regarding probable cause of the tiny craters?

Am I focused on the likely cause?

Might one of those M-60 filters help me out with this in the future?

Anyone tried to take corrective measures on these? ... short of sanding the whole thing down and repaint?

Feeling pretty lonely out here.

OK, they look like fish eyes from some type of contaminate. its hard to pinpoint but yes start with a new air hose, drain your compressor tank regularly. you can take a tooth pick and dob a drop of paint in the crater, you did catalyze your color? then use a clean spreader or something and squeegee it off. if you leave the drop there it will take for ever to dry hard. let it dry a few days 3-4 then lightly sand with 1000 or 1500 and buff. you want to make sure its good and dry if not the buffer will tend to pull it right out.
on the filter the m60 has been in use for ever it seems to work good. I just run a couple good water traps back to back inline and a dedicated hose for paint only. I never have problems now. but I have had them, hard to figure out sometimes. I have a friend that does a little painting, he has a nice four bay shop with the end stall made into a paint booth, he also has one of the m60 filters. he started getting contaminates in his work, looked like minute chunks of something. he started going back through his massive air system and found nothing. first thing I ask was did he change the filter, YES he said look he pulls the top off the filter and puled the filter out and there were small flecks of something on it. looking inside the coating on the inside of the filter was flaking off and going out to the gun and onto his paint. its up to you about the filter it sure can't hurt anything unless the paint inside the filter starts to come off.
no need to feel lonely anymore.
Jay D.

Thanks Jay. Sounds like your perspective follows fairly closely with what I was instinctively thinking.

I think I'll get that M60.

All of this problem is on one side of the car ... the side I started spraying on. It's also most heavily concentrated on the roof, where I did the very first passes.

I do think with the M60 and a dedicated paint hose I should do much better.

I can add: For my very first big spray job It is buffing out fairly nicely. Aside from these little annoying craters I did get quite a bit of orange peel, mostly on the roof. The orange peel is sanding and buffing out to my satisfaction, though there will still be some peel visible ... I can live with it. Lesson learned.

I'll take a stab at *touch-up* on some of the craters. The ones on flat horizontal surfaces should be easiest to work with. Some though are on vertical or sloping panels ... a little more complicated.

Per your recommendation (Jay) I turned the air pressure up (on my Binks gun) when I sprayed the rear spoiler, it has turned out quite well. If the whole car could turn out as good as the spoiler I'd be 100% proud of the job.

I still have all of the front (fenders, hood, cowl, everything in front of the doors) to go.

More opportunity to prove to myself that I can do better.

Thanks for your input Jay, I appreciate it.

when you do the dob thing don't reduce your paint, use it unreduced you might check for air born contaminates. I had a car in my booth that has a side door into my shop. the car was covered with fish eyes on one side and part of the roof area. now I never get fish eyes i'm very anal about my prep work and tools. after a little investigating I find a can of WD-40 on the floor of the shop area, just so happens my boy and a couple of his buddies were in the shop lubing the chains on there bicycles. the side door to the booth was open and the mist floated in the door and on the side of the car 30 feet away. even contaminated dust off the floor can cause problems. kinda makes me wonder were you've got problems on one side or one area.
Jay D.

badsix wrote: kinda makes me wonder were you've got problems on one side or one area.
Jay D.

I have no other people out in the garage doing anything, so whatever it is ... there is no one to blame other than yours truly.

I did wipe the whole car off with an approved wax/grease remover about an hour before painting.

I'll be paying better attention in the future, but I'm getting that dedicated hose before I spray a large job like this again.

That hose I *stupidly* used is the one I use to run the sand blaster, air up tires, etc. all the stuff where I'm not concerned about clean air.

I did not use that hose to spray the spoiler, I used my workbench hose that is always hooked to the filtered air. Result was beautiful.

I'll be learning as I go, that's for sure.