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Fisheyes

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TR4eh

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Grump. Nothing positive accomplished today. I have some bare metal brackets to paint. After cleaning with PPG DX330 ('Acryliclean') the self-etching primer made numerous fisheyes. Looking for advice on what else I should have done. Wipe down with lacquer thinner or some other solvent? Thanks.
 
Fisheyes, I'm taking a guess this time of year your metal was cold, it must be warm to get the paint to stick, not hot, or it will fisheye real bad. Wipe it down again and put it by the fire place or stove for a few minutes. If you can't pick it up, it's too hot!!

Wayne!
 
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Fish heads Fish heads Rolly Polly Fish heads, Fish heads Fish heads eat em up yum.

I'd sand down and start over, maybe give them a little more time to dry. Did you make sure the filter for your gun was good?
 
Hmmm, garage was a bit chilly, around 55F and the metal was probably a bit cooler. I'll get the worklamp out and shine it on the brackets before I spray again. The paint was warmer, I had it in the house. I'm using a new rattlecan of primer and the paint shop put the base coat in a spray can also.
 
Just a thought, have you blown anything off in the garage with compressed air recently? Few years back, I tried 3 times to paint a small panel inside the garage and got fish eyes no matter how well I prepared. Then I tried it outside and it came out perfect. Evidently, some activity the day before had left microscopic droplets floating around and 2 or 3 of them would land on the panel while it was wet.
 
Agree with all that has been said, sort of similar to Randall, I got Fisheye on certain panels when I painted my TR4A years ago, I think it was well cleaned but small particles were being blown out of the engine compartment, which wasn't sealed well enough (fisheye was worse the closer to the engine compartment you got). In addition to possible temp issues and airborne particulates, you might scruff up the surface with some 400 or 600 grit to give it a little bite if it us super smooth (then of course you have to clean it all up again) shouldn't hurt, might help.
 
I don't know what paint was mixed for you, but most is temperature sensitive. There are a minimum of three thinners/catalysts for different temps. You might have to have some mixed for cold 65-80 deg.
 
Bummer!

55 degrees should be alright for the DX330, although it's always best to have paint and part at the same temp.
I don't think that caused the fisheyes, though.

Fisheyes are always caused by contaminant on the part. In that cold, the most likely cause is that the cleaner did not have time to fully evaporate before you sprayed. It settles in to little imperfections, like little land mines ready to destroy your spray!

I tried many of the recommended "cleaning" products over the years, but found they evaporate much slower than simple laquer thinner. I now always clean with the same thinner I am using in the paint I plan to spray. Then, leave enough time to make sure it evaporates. Just remember, at 55 degrees evaporation is pretty slow, so wait a good 30 minutes or so.

I know how you feel...been there many times...

John
 
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There could be many causes, but I suspect John is right, I have used a few different cleaning products, and some that don't evaporate as fast have caused fisheye. The Acryliclean is one of the better ones, but at lower temp probably takes more time to dissolve. The lacquer thinner is a good idea for clean metal, but I don't think I would use it for a primed surface, might not play well with the primer.
 
So far so good. Garage just won't get up to temperature but the halogen worklamp gets the metal bits warm enough. I sanded down the bits, cleaned up the workbench, cleaned the bits with DX330, then 30 min under the heat lamp, and the primer was still making fisheyes. Sanded, recleaned, a very light wipe with lacquer thinner, 5 min under the lamp and the primer makes a nice smooth coat now. In an hour or so we'll see how the base coat lays on.

I appreciate all the advice and especially the moral support as I am repainting in tackcloths and washes :)
 
I have an unorthodox pre-prep step to suggest. You may have a bit of silicone on the surface and some prep solvents have trouble removing them. If you wash/wipe the surface down using a mixture of gasoline and caustic cleaner you can often remove those contaminants even from a surface with a bit of porosity (such as a surface chemically treated to remove rust). A few washes/wipes with gas mixed with something like one of the "purple" degreasers (followed by rinsing with clean water) BEFORE your normal panel prep may get the remaining bits of contamination off the surface.
 
I've tried a lot of different cleaners and always come back to laquer thinners, even after sandblasting. Cleans real good and evaporates fast. Never had a problem after I started using it as a final bare metal wipe.

Derek K
 
Fisheyes can have nothing to do with contaminants on the surface. When spraying your first coat of epoxy primer on bare , properly prepped metal always spray a very light even almost transparent coat first and let the solvents flash completely before continuing. This is what a tack coat is . Once the solvents have flashed and the surface is dry to the touch you can spray another light coat to cover the metal. Once its dry spray a full wet coat.
 
So, base and clear coats layed down nicely. I think the success is due to 1) heating the garage (got to low 60s); 2) using a worklamp to warm up the parts; 3) lacquer thinner wipe; and 4) learning the right amount of pressure on these spray can buttons. I'm only painting small bits and don't want to clean up my gun. The primer issue was partly due to being too careful with the spray can, I wasn't pressing firmly enough and was intermittently getting only propellant without paint.
 
Oh, I didn't realize we were talking about spray can primer. I have always had mixed results with the canned stuff. I think the problem is that primers have a lot of solids, and they settle to the bottom of the can. It's very hard to get them mixed back in by shaking, and if you do, they tend to gum up the nozzle...bit of a lose/lose...fisheyes or plugged nozzle.

The odd thing is that I have great luck with the cheapo $1.29 per can paint from Walmart or Home Depot. I sometimes even spray parts fresh out of the kerosene washer with no problems! The expensive paint, like PPG, Dupont or Rustoleum will fisheye with even a little oil or silicone on the part. So, whenever I don't feel like dragging out the whole spray rig I always go with the cheap stuff. As long as the surface is roughed it is as durable as any of the good...I mean expensive... canned paint.

John
 
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