Fish eye? Clear coating issues

[TAftonomos]

I'm a complete NOOB when it comes to painting.

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 table, 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.
Lines are "M" copper, 3/4".

Attached is the headache that is happening time after time after time. I've attempted to spray parts 3 times now, with varying degrees of issues.

ONLY things I can think of are:

Water I'm using to wash off the part after patining the surface is somehow contaminated?

Hose that I feed the airgun with is contaminated with oil. It's an old hose and has been used for years. I'm fairly confident that the filters and drier and stopping anything but could the hose be contaminated and that contamination getting past the filter on the gun as well?

 

[HMCFab9]

I'd clean the steel before you cut it, after you cut it, before you treat it & again before you clear it. (if clearcoat is what you are doing).
The metal has oil on it when you get it (clean that off)
You NEED to use a pre-paint cleaner to do anything before coating. I'd clean the metal with paint thinner before you do Anything.
Before you clearcoat it, you Need to use a Wax & grease remover. Water will do NOTHING to clean it, besides clear the dust off.
Wash it with PPG DX330 before you clear.
The other possibilities are: do you have an air line oiler somewhere? Is your hose contaminated? Is it a silicone hose? Has the hose EVER been used with an oiler? (if so, don't use it)
If you prep it correctly & it still does this, get different hose & get a filter that screws right on your spraygun.

 

[mo2872]

^^ Oiler, or water in the lines, was what I was thinking. Been wrong before, though.

 

[TAftonomos]

The steel is cleaned and then "polished" with a new flap disc (120 g) before it is coated.

The air system is copper lines, filter, refridge/dryer, then another filer.....then one just before the gun


No oiler anywhere.

Dunno if it is a silicone hose....its rubber and orange in color.


You can't put any solvents on the steel after its been treated....it will strip off the patina. This isn't a new process and there are others that are doing it....just need to figure out what I'm doing wrong..

 

[mharmon]

Did you disassemble and clean the purple gun before use? They are known for having a silicone caulk behind the air cap. Take it fully apart and clean it with solvent. It should help fix the problem if the rest of the prep is done correctly.

 

[mharmon]

Btw. I have had similar problems with the same gun painting a car and solved the problem by cleaning it after some Internet research. After cleaning problem significantly was decreased.

 

[Crow11]

Are the air hoses ever used on un filtered lines? Were they new or previously used? Have you tried spraying various pices of scrap. Each one with one step of your prep process to see which is the worse?

Most metals are coated with a protectant against rust. Which should be removed prior to any tooling as sanding can imbed the anti rust coating and or contaminate the paddle wheel and basically smear it around. It takes such a small amount of oil to cause a fish eye.

You may also want to try a fisheye/crater reducer/eliminator additive.
http://www.cloverdalepaint.com/contractor_professional/product.asp?code=A69

 

[C96]

It sounds as though your covered filter wise, so I’m going with the theory that your metal is still contaminated. Hell, you can pick-up contaminates just in the atmosphere.

Your metal must always be clean!

Another thing you can try is a good fisheye eliminator. I have always used these products when painting cars as a hobby in not so perfect conditions.

Here is one I have used many times with very good results.

 

[nehog]

Did you add an anti-fisheye additive to the paint/clear coat?

 

[BRENT in 10-uh-C]

Plenty of good advice above and the only thing that caught my eye is you said you force-dry the piece, any chance you are getting contamination from that? Also, the picture is tough for me to see distinctly but water can cause symptoms as you are showing as can severe cases of solvent pop.

Let's talk something from here forward. You did not mention whether your clear is 2k but I think I would allow the clear on the item to dry completely, then use a gray Scotchbrite (-not Red) to lightly scuff the surface. Just do it enough to get a complete mechanical bond over the entire piece. Air blow dry the piece but do NOT use any towel to wipe it down. Put some Wax & Grease Remover in your spray gun and spray a medium coat and then quickly blow it clean with compressed air. Now re-coat with more clear and see if the fish eyes return. I feel this will give you some insight to where your problems are originating.

 

[Kevin54]

What sort of "patina" are you coating the steel with that can't have any other chemicals on it? I would think that you could use a pre-cleaner before you clear. Also are you using a tack-rag to wipe it down and remove any dust right before spraying your clear. Pre-Cleaning and tacking off, are two of the most important steps before pulling the trigger of the gun.

You say that you have a filter at the gun for water. I am assuming that it is a ball filter?

Take your gun off of the hose, and put on an air nozzle. THen get a clean piece of brown cardboard, and just blast air onto one spot on the board and just see if you are by chance getting any moisture. If you are, it will show up on the brown cardboard rather quickly. Do this long enough that the compressor cycles once or twice.

Another thing to do is when you are getting ready to spray your part, get another piece of steel that is not patina'ed and wipe it down good with a pre-cleaner and a tack rag and spray it first. If you don't get fish-eyes, then your patina is contaminating your clear, or you will need to pre-clean, and most definitely tack it off.

Make sure the rags you are using are a proper rag for pre-cleaning. You can buy bundles of them at your local jobbers, or order them through TCP (Autobody Color) The towels have no contaminates in them. If you are using something that came out of your washing machine, they may have fabric softener in them.

I'm interested in what you are using for the patina, and I'm leaning that it has something to do with it. Clearcoat is some great stuff, but it has to be compatible with other chemicals. And if you are putting a patina on sheet steel, if you are using more than one chemical to get there, it may be just the one chemical or combo of more than one. If you are only using one specific chemical, then you will have thinner and thicker places of the chemical. And if you are not using a pre-cleaner, most pre-cleaners / wax and grease removers are formulated to not affect chemicals/paints/primers that you are using it on.

Brent said something that I completely forgot about.....Solvent Pop. It may not be fish-eyes at all, but it could be solvent pop causing it. If you look real close and even under a magnifying glass, you can tell the difference between the two. Solvent pop will be more of a raised area. A bubble per say, that pops and opens up. Fish-eyes usually have a little minute spec of dust, or it could be silicone in the air that has settled on the piece, and the clear will push away from whatever is in the center. The clear will be more flattened out that what a solvent pop area is.

One other thing to do to.....make sure you drain the tank of your compressor so that you won't have water in there.

 

[mikewatson]

+1 solvent pop. fish eyes show right away when you clear. if they show up after you spray ..solvent pop ,is to much material on the panel before the next coat is applyed or to much at once+ you need air flow so it can breath while drying.

 

[BFBOB]

I realize this may be heresy, but have you tried a rattle can clear? Rustoleum makes a good high gloss coating I've used mostly for glossing up a flat or satin paint. No good on large areas, of course, but I can't tell the size of your pieces.

If it's not acceptable for the actual finish, at least trying it out would isolate the cause of your problems by eliminating all the contaminated air or spray gun issues. If you still have fisheyes with the rattle can, it's definitely a surface prep problem.

 

[TAftonomos]

Thanks for all of that advice!

I've sprayed with clear in a can, both rustoleum and the 2K spray max - no issues.

I'll pull the gun apart as far as I can today. Wasn't aware that you could disassemble it more than just the needle/tip/nozzle and cup.

How should the clear look after the first coat? Should it be grainy and dry spray looking or a single coat of "glass" ?

 

[Flexia]

I have seen spray deodorant on people cloth cause fish eye also

 

[TAftonomos]

I'm not opposed to making mistakes, or encountering problems....I expect a learning curve.


I took off the end/nozzle? of the gun....inside I found this:




And this:





I'm really hoping this is some kind of silicone lube **** that I didn't get out of the gun to begin with.

I checked the gun empty on a piece of cardboard - zero water running for 5 mins straight. Got some funny looks from the wife when I was doing that.

 

[theoldwizard1]

They do make an anti-fisheye additive for varnishes. I don't know if it would work with clearcoat.

 

[Kevin54]

I'd say by the looks of the inside of the gun, that is a lot of your problem. You can clean everything with lacquer thinner, but if you are going to be using the gun quite a bit, look into getting a gun cleaning kit. It will come with various size of wires for cleaning out the small holes, along with various small wire brushes to get into and around everything else.

And never let a gun sit without running some lacquer thinner through it when done. Spray the thinner through it, then take a rag and cover the front of the gun, and make sure your air pressure is down. This will let things blow back into the gun into the cup and agitate. Afterwards, pour the thinner that is in your cup[ into a coffee can, or an empty soup can and soak your parts while you are cleaning the rest of the gun out.

 

[mikester]

I'd say by the looks of the inside of the gun, that is a lot of your problem. You can clean everything with lacquer thinner, but if you are going to be using the gun quite a bit, look into getting a gun cleaning kit. It will come with various size of wires for cleaning out the small holes, along with various small wire brushes to get into and around everything else.

And never let a gun sit without running some lacquer thinner through it when done. Spray the thinner through it, then take a rag and cover the front of the gun, and make sure your air pressure is down. This will let things blow back into the gun into the cup and agitate. Afterwards, pour the thinner that is in your cup[ into a coffee can, or an empty soup can and soak your parts while you are cleaning the rest of the gun out.

Go to the nearest Advanced Auto Parts and buy the set of spray gun cleaning brushes. The set is about $9.00. Use the round brushes dipped in lacquer thinner to clean out the head of the gun. Be VERY careful with the thinner because some of the knobs on the HF guns are chrome covered plastic and they will melt if you soak them in thinner. I KNOW THIS FIRST HAND !!! That's why the guns are so cheap.
I bought a set of the Devilbiss Starting Line guns and even though theyre not expensive I take them totally apart to clean them every time I use them.
As far as the fisheyes, your lines might have been contaminated. I had the same issue. I wound up buying a new hose. If you use a wax and grease remover try to get one that's not solvent based. It can leave a film on bare metal. Theres one made that doesn't leave a film. Not sure if its alcohol based but I think RM makes it. One of my friends recently suggested it but the last time I sprayed something it was bare metal that I cleaned with lacquer thinner and then denatured alcohol.

 

[TAftonomos]

Don't have the part number handy for the clear. 60 something....not the speed clear. I'm using slow hardener mixed 4:1


I cleaned everything twice, and then once more.

Just tried spraying several test panels. On the second coat....whala....hundreds of little pinholes. Some were bare steel, some were patinad metal. Some were previous screwups that were sanded /washed then wiped down with w/g prior to spraying.

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

 

[akdiesel]

Im not a pro paint sprayer but I have had the same issues and some people told me the pressure needs to be turned down.
Have a pre-filter and regulator on the gun.

 

[TAftonomos]

Gun has a pre-filter on it.

Next stop buying more clear...burned through a quart already.

Pressure on the regulator with the trigger depressed was 40psi.

Too high?

 

[akdiesel]

I thought they had to be in the 20 psi range, but hopefully some one with more experience with chime in.

 

[Burmashave]

Your last screw up was a blessing in disguise! If your first coat didn't fisheye, then that rules out surface contamination. Before we go further, a few questions.
1. Do you have an air regulator at the gun? This is important, what I tell new guys is to turn it down till it sprays like ****, then turn it up till it lays out. 40psi, if at the gun is way to high. All you need is just enough pressure to atomize. More than that and you are just wasting product by spraying outside the guns"s efficiency range.
2. When the second coat fisheyed, did the compressor happen to kick on at that time?
3. What is the exact clear you are using, brand and product number?
In response to your previous question, your first coat should go on medium wet. That means no dry spray or roughness. I spray at roughly 6" distance, 75% overlap, about 3 feet per second. That being said, spraying on top of bare steel, the clear won't lay down the same as it does over base coat. Your second coat will go on roughly the same. You are ready for second coat when you touch the clear and it is sticky but doesn't transfer to your finger. Flash time will vary with temp/humidity/air flow/ solvent choice.

 

[Burmashave]

Also, how long is the line between the compressor and the refrigerated air dryer?

 

[TAftonomos]

I was incorrect...it fisheyed on the first coat. Won't if I just "dust" it or tack coat it. But anytime I put on a decent amount of clear.....hundreds of voids.

Gun has a filter on it and a regulator.

I've sprayed the gun dry at a piece of cardboard for 2 mins straight...nothing but air is coming out. No water, no oil....nada. Compressor cycles as well.

Line is approx 5' before it gets to the first filter/water sep, then another 5-10' before the dryer, then another filter after the dryer....then the prefilter on the gun. All hard airline is 3/4" copper. I have drops in 3 different places. I have never had any water drain from the drops.

I bought a preval sprayer this evening. I plan on testing that out tomorrow. If the clear lays down fine with that I've either got a air problem or a gun problem (Or applicator!). If it does the same thing in the preval then it's either the clear or the part(s) are contaminated.

 

[TAftonomos]

If I can lay down a nice looking coat of clear with a simple spray can (not 2K, just some junk from home depot).....does that indicate that the part is not contaminated? Wouldn't the spray paint fisheye as well?

I ask because I've never had an issue painting with the simple clear from a spray can.

 

[TAftonomos]

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 **** 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.

 

[Kevin54]

I was incorrect...it fisheyed on the first coat. Won't if I just "dust" it or tack coat it. But anytime I put on a decent amount of clear.....hundreds of voids.

Gun has a filter on it and a regulator.

I've sprayed the gun dry at a piece of cardboard for 2 mins straight...nothing but air is coming out. No water, no oil....nada. Compressor cycles as well.

Line is approx 5' before it gets to the first filter/water sep, then another 5-10' before the dryer, then another filter after the dryer....then the prefilter on the gun. All hard airline is 3/4" copper. I have drops in 3 different places. I have never had any water drain from the drops.

I bought a preval sprayer this evening. I plan on testing that out tomorrow. If the clear lays down fine with that I've either got a air problem or a gun problem (Or applicator!). If it does the same thing in the preval then it's either the clear or the part(s) are contaminated.

Chances are that is SOLVENT POP. You're trying to build it up too fast, and the solvents aren't having adequate time to evaporate.

I understand what you are saying what you are doing, but I don't think you are understanding some of the replies as to how to go about getting a good finish without problems. And please don't take it the wrong way, as we're all trying to help you out.

What are you washing the material with when you say "You are washing it, then force drying"?

 

[Kevin54]

Okay....this is straight out of a DuPont paint book......

Solvent Popping - Description - Blisters on the paint surface caused by trapped solvents in the topcoats or primer surfacer - a situation which is further aggravated by force drying or uneven heating.

A smooth blister or bump in the paint film (hollow, not solid).

Some blisters may have "popped" and leave a crater like depression behind.

Commonly found on horizontal surfaces.

PROBABLE CAUSE - Improper surface cleaning or preparation.

Wrong thinner / reducer. Use of fast drying thinner/reducer, especially when the material is sprayed too dry or at excessive pressure, can cause solvent popping by trapping air in the film.

Excessive film thickness (insufficient drying time between coats and too heavy of application of the undercoats may trap solvents causing popping of the color coat as they later escape)

Too low or too high of air pressure

Not sufficient flash off time prior to force drying

FIX - if damage is extensive and severe, paint must be removed down to undercoat or metal, depending on the depth of the blisters, then refinish. In less severe cases, sand out, resurface, then retopcoat.

PREVENTION - Use of correct solvent for shop conditions
Watch film build
Allow proper flash time between coats - DO NOT fan


I have a complete bunch of problems and solutions out of a DuPont book.

 

[Kevin54]

I'll see if I can scan the page on Fish Eyes, and post it here.

Sorry that it's upside down.

 

[Burmashave]

I seriously doubt shopline clear is solvent popping over bare metal (I'm a PPG distributor).
Which shopline clear is it? There are several and they handle differently.
Since you were mistaken about the first coat fisheyes, that changes my guess about air contamination though it doesn't rule it out completely. The reason I asked how far the ref. dryer was from the compressor is that the line needs some distance to allow the air to cool enough for condensation to form. Too close and the dryer isn't effective.
Fisheyes don't necessarily mean contamination. Mill scale is difficult to completely remove and will cause fisheyes. What are you using to patina the metal?

 

[Burmashave]

Btw, solvent pop can look like tiny fisheyes but not like the large fisheyes in your first pic. I seriously doubt you applied enough material with the preval to cause solvent pop, especially before the second coat. Shopline clears are intended for low end shops and the limited airflow usually associated with them, not likely to pop as a rule.
Your quickest solution may be to use a little fisheye eliminator when you spray. If you were spraying cars, I wouldn't suggest it but in this case...

 

[Burmashave]

I wouldn't dust coat it, but if a tack coat works and eliminates the problem there you go.

 

[TAftonomos]

Chances are that is SOLVENT POP. You're trying to build it up too fast, and the solvents aren't having adequate time to evaporate.

I understand what you are saying what you are doing, but I don't think you are understanding some of the replies as to how to go about getting a good finish without problems. And please don't take it the wrong way, as we're all trying to help you out.

What are you washing the material with when you say "You are washing it, then force drying"?

Not taking anything the wrong way

I should have said rinsing. Rinsing with water. Then drying it off with compressed air.



I did this same thing this morning, except I sprayed it with a preval sprayer and some of the same clear. Finish came out great/no voids or fisheyes. A smidge of orange peel but that is it.


If the paint is good, and the surface prep is good.....that leaves the air supply or the gun.

Correct?

 

[TAftonomos]

Btw, solvent pop can look like tiny fisheyes but not like the large fisheyes in your first pic. I seriously doubt you applied enough material with the preval to cause solvent pop, especially before the second coat. Shopline clears are intended for low end shops and the limited airflow usually associated with them, not likely to pop as a rule.
Your quickest solution may be to use a little fisheye eliminator when you spray. If you were spraying cars, I wouldn't suggest it but in this case...

Too many posts now, I think people are confused.

The PREVAL sprayer produced a NICE/ACCEPTABLE finish.

This leaves either the gun or the air supply as being contaminated. I don't see how the air supply is bad, but I will have a thorough look at it tomorrow morning.

 

[Dusty-NZ]

The pics of the grease in the gun head are amazing .

Maybe your definition of clean is different to the guns idea of clean.

Respectfully .

 

[TAftonomos]

Thanks for reading Dusty, your comments are very helpful! I'm fine with admitting I'm wrong, and moving forward from there. No big deal!


Respectfully...

 

[TAftonomos]

Found the problem...

The HF gun had a ton of oil and grease inside the handle/air inlet. I didn't have a container large enough to submerge the gun....after I found one and did just that....no more problems

 

[akdiesel]

good find. Hard to trust a new product out of the box these days.