Tired of ruining pieces! What am I doing wrong, Clear Coat?

[Cracker Red]

I'm so sick of messing up really nice things I've made, I don't know what to do.

I AM in the process of building a downdraft booth like Marty, but in the meantime (next 3 weeks) I need to figure out just what is going wrong.

I strip the pieces, patina them, force dry them. Then I wet down the area outside where I'm going to spray. I don't touch the pieces I'm going to clear on the front, I only move them from the side wearing a new pair of gloves.

The gun is the HF purple one, with the regulator on the bottom. I BELIEVE I have it set up correctly, but I'm open to ANY suggestions. I'm using the same air that I feed my plasma, which is filtered after the compressor, then into a refridge/dryer then another filter. There is also a pre-filter on the gun itself.

Attached is the headache that is happening time after time after time. I might get one nice 10% of the time.

[Cracker Red]

Ordered a Iwata spray gun (air gunsa) and a 3M PPS system.

I'm wondering if an air hose that I used long ago might still be contaminated with oil? I never had the need to have super clean air, so I used this hose on a reel for ever (It's probably 10 years old).

Could/would it still be contaminated? If it is, would there be a chance it's getting past the filter on the gun as well?


ONLY other thing I can think of is perhaps the table isn't clean, and it's kicking up dust when I spray. Not sure about this...as last time I sprayed the pieces were hanging and I got the same outcome as pictured.....

[Cracker Red]

Cleaned everything twice. Replaced air hose.

Just tried spraying several test panels. On the second coat....whala....hundreds of little pinholes. Tried it in a piece of steel bare, piece of patinad art, piece of raw hot rolled, piece that had been previously cleared , sanded and degreased. Same result.

I seriously feel like throwing in the towel. This **** can't be THIS hard...

[redduke]

Looks like fisheye to me. Amour-All or anything with silcone floating in the air. Will not let anything with silcone in or near the shop. You could try a fisheye eliminator in the clear.

[Cracker Red]

Could the steel be "bad" in some way?

Am I screwing up finishing it and grinding junk into it? The hot rolled stuff gets muratic acid washed then rinsed prior to grinding. Gets rid of the mill scale and dross. I grind with a fresh 120 flap disc. Then wash, patina, wash, force dry.

At this point it takes me 10-15 mins to setup to spray. I hose down the bench again and blow it dry. I make sure the piece is dry again prior to clear coating (and ruining it!).

Hit the piece lightly with a tack rag prior to spraying.

Boom....pinholes everywhere. A few people locally swear this will never work unless I wash the metal with degreaser prior to spraying clear....yet Bill and others say that is not necessary. I haven't tried it, but I suspect it will wipe off any patina finish.


I'm so frustrated because this is the difference between making garage sale wall hanging bits and 300$ turtles and $1000 pieces of art. I've got the plasma cutting down, I'm getting pretty good with the patina part as well.....but all is lost when it's ruined with a garbage clear finish.

[redduke]

You are calling it pinhole. Does it look like a crater ? What kind of clear?

[Cracker Red]

Crater yes. Tiny ones....hundreds of them.

Shop line 2k mixed 4:1 with the slow hardener. No reducer.

Using laquer thinner to clean the gun between disasters. Would the thinner be causing this?

Not sure if its relivent or not...but I can spray the junk clear from a can without having these fisheyes at all....

[m79b01]

How long between coats?

[muzza]

Many people using a HVLP gun or using 2K when not familiar with them will get "Solvent Boil" most often caused by spraying too heavy or incorrect consistency of paint especially in clear coats as most 2K clears nowadays are high solid.
Google "Solvent Boil", may help.
Murray

[Cracker Red]

None....its doing this on the first coat. If I try and bury it some of the pinholes will go away...but larger ones form up.

Obviously you cant bury them...

[Gamelord]

It looks like out-gassing to me. When you grind, are you using a new disk or one that has been used on other metals that have oil or gunk on them? You may be grinding oil into your metal. To try an eliminate the problem I would try a metal etch or very good degreaser or thinner or something. If it works then great, if not then at least you know that isn't it.

Could also be a reaction between the patina and the clear...but I can't see that. Have you tried it on a piece that hasn't been patina'd? Again, just trying to eliminate the obvious.

[Cracker Red]

OK...progress.


Mixed up the small amount of shopline that I had left (about 3 ounces total).

Strained it into a preval sprayer (little aerosol can with a glass jar/pickup).

Made a test piece, patina'd without any wipe down. Ground 120grit, washed, force dry, patina'd, rinsed, force dried.

Shot it with the preval. Zero defects....save for the orange peel on the second coat. My fault...rushing it, a bit to close I believe, but it's coated....and looks pretty darn good. Has less peel than a new vette.

In ANY case....either my air is bad (I still don't know how?!?!) or I've got some crap in the gun.

If the hose that I'm using is contaminated.....would that stuff get past the prefilter on the gun? Could I see it in the prefilter if I cut it apart.

[abmetal]

I'm with Redduke...use fisheye eliminator. I've always used it whether painting cars or signs.

Allen

[ColoradoWayne]

It has been a couple weeks since your last post. What did you figure out? It sounded like you were getting where you wanted to be. Was a new gun the solution? Just curious, getting ready to start clear coating for the first time next week.

[Cracker Red]

Problem was the air supply!

The prefilter, the post filter and the air dryer all work very well to pull all the moisture out of the air. What they wern't taking out of the air was some very fine oil mist/vapor. I can only assume the compressor I have is on it's way out.

To remedy the problem I installed a M60 motorguard filter by the paint booth, and another M60 for the supply of the plasma/air hose that I use to dry off pieces to patina.

So far after a weeks use I cannot see anything visually changing with either filter.....but the painting problems have ceased!


What I thought couldn't have been the problem....was the problem.

YOu don't know what you don't know

[Minigunner1980]

I have seen this with car paints it can be silicon in the air like calking or spray anything containing silicon can cause fish eyes