Contaminated Finish

[Russell Tribby]

I only spray water based finishes, the vast majority of which come from Target Coatings. I do occasionally spray some water based acrylic from SW. The last couple of times I've sprayed my clear coats I will periodically get white flecks of paint coming out of the gun, some of them so large that they clog up the nozzle until I open it up a lot more and they get pushed out. I've flushed everything out with water and DNA but I still get the paint flecks. Will running some lacquer thinner through everything dissolve whatever is in there and get me in the clear? No pun intended

[Mark Kornell]

If you've got dried acrylic in your gun, just flushing with DNA won't do much. Flushing with lacquer thinner would be better, but probably not enough.

I shoot Target 9000SC regularly and occasionally have that happen when I haven't cleaned the gun properly. The solution is to soak the nozzle and air cap overnight in acetone, which does a great job dissolving just about everything.

If you've already got some lacquer thinner, do an overnight soak in that, and then scrub your nozzle and air cap well , including using the appropriate cleaners in the holes in the cap and nozzle. Also, thoroughly scrub the fluid channel in the gun with lacquer thinner.

[Scott Holmes]

Also make sure you run all your finishes through a mesh filter to remove any clumps before you put it in your sprayer.

[Russell Tribby]

Thanks guys. I'll try the acetone. I filter everything so that shouldn't be causing the issue. I'm guess it's material that's dried on the inside of the hoses, gun, or intake tube in the pressure pot.

[Russell Tribby]

Thanks for the advice, Mark. The acetone did the trick. I'm embarrassed to mention how much gunk came out of the hose when I shot the acetone. It certainly gives me peace of mind for tomorrow when I'll be spraying my clear coats. Thanks again.

[Rich Engelhardt]

I only spray water based finishes, the vast majority of which come from Target Coatings. I do occasionally spray some water based acrylic from SW.

Don't be embarrassed in the least.
More years ago than I care to remember,,,,,,NASCO Solvent Corp. came out with a Latex Paint Cleaner.
As can be expected,,,it bombed out really bad.
Everyone **knows** that you clean up latex with soap and water right?
Who needs an expensive cleaner for that when all you have to do is open the tap.

Well, here's the thing.
Water is the carrier for all waterborne (hense the name - waterborne) coatings, not the true solvent.
All waterborne coatings can be drawn out to infinity - similar to adding DNA to shellac - you never really break it down, you just extend it.
Anyone that's ever washed out a brush or roller under running water can attest to how there never seems to be an end to cleaning them.
No matter how much water you run, there's always more coming out of the brush/roller.

Shellac and 95 + % of all waterborne coatings also share another common item - that being the same solvent - ammonia.

So,,,,,next time you clean up after using any waterborn - run some ammonia & water through before a final rinse.
Just make sure to flush out any trace of the ammonia.

[Jim Becker]

Not unusual at all for something like this to be overlooked, especially by those of us that are hobbyests and part-timers. I remember about a year ago when I realized that my gun really had far too much gunk in it for its own good...and mine. I did get away with soaking some things in lacquer thinner, but acetone is a helpful solvent for this, too. Be sure to do said soaking and cleaning outside, however...the fumes from lacquer thinner and acetone are nasty and dangerous.

[Mark Kornell]

Thanks for the advice, Mark. The acetone did the trick. I'm embarrassed to mention how much gunk came out of the hose when I shot the acetone. It certainly gives me peace of mind for tomorrow when I'll be spraying my clear coats. Thanks again.

You are welcome. I'm not sure I would have shot the acetone, but that may be the easiest way to clean a pot & hose.