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Anyone have any tip for dealing with fisheyes with waterbornes? I recently switched to using KTM-9 with an epoxy sealer. I was doing some test panels and had a few pop up. With solvent based stuff we would typically wait till dry, sand, then wipe down with naptha. Havent delt with fisheyes for a long time. I think what happened is that I sanded the Epoxy down a little too far in a few places.

Josh

Just keep on truckin.
Sand it after a days coats or rather before you spray more coats and you can use Naptha to clean it before you spray. The fisheye is fairly common on the first few coats.

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Tickle your guitar daily, and it'll tickle you back.

Any spray cans used recently? I wanted to "spray-bomb" a motorcycle fuel tank and side covers at the cabinet shop my brothers-in-law have, but my wife says they use water-based finishes there and fish eyes can result from the contamination.

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DES - Shepherd, MI

I can see two potential sources of the fisheyes. 1) Like Darin said, you might have contamination on the plate. Something like WD40 will stay in the air much longer than you might think. When I was at CFox, there was a batch of guitars that had fisheyes with the nitro. Now Charles had an incredible spray booth and had the finishing system mastered. This just started out of the blue. After lots of investigating, he found that someone was working on an airconditioner and used spray silicone to lube it. That got into the ductwork and then eventually into the shop and on the guitars.
2)if indeed you sanded through the epoxy, that area might be gassing out. When laying fiberglass on a wooden boat they say to do it at the hottest part of the day so that the gas in the wood is as expanded as possible and doesn't try to get out. Once the wood is completely sealed, this is no longer an issue.
Id say keep spraying and see what happens.

Thanks for the info. Well, day two came and I sanded down with 320, wiped with naptha, let dry, wiped with DA, and shot another coat. No problems at all. However, with the next two coats more fisheyes popped up. Wierd. It seems to be building, so I guess I wont worry about it. I'm shooting my last 3 coats today.

Possibility of a contaminate in either you Naphtha, DA or your finish. or maybe if you have an oil lubed compressor there is oil or maybe water getting in the air stream.

I always get a little of that with the first coat, but after sanding and cleaning, no problem and I have never had any adhesion problems with the stuff either.

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Tickle your guitar daily, and it'll tickle you back.

I get a bit from time to time, no adhesion problems either. However if it pops up repeativly I would check my system to make sure I don't have contamination issue.

what sort of filters are you running on your air? when was the last time you drained the tank, cleaned the reg. bowl, changed filter elements, etc.?

Gun is new HVLP(never used solvents with it). Filter is a new large devibliss type with 5 micron filter. Compressor tank gets drained everyday. The fisheye wierdness doesn't seem that bad, just seems like some lower spots in the finish - still seems to be building fine. FWIW, I repeated the sanding/naptha/DA and shot the first coat a while ago and no problems. It only affects the subsequent coats. As long as I can get a smooth finish upon rubbing out I'll be happy.

all good tips, so far. One thing not touched on is that you may have a contaminated batch of KTM. If you used a stcik, for example, to stir it, and something was on that stick, you can have a contaminated container. Or it could have happened at the factory, where they make the container, where the wash it, etc.... Happened to me, last summer, in my testing of waterbornes. Was finsihing up one quart, and all was perfect, then started mixing finish from a fresh can, and fisheyes everywhere. Turns out it was the new one that was bad, and not anything I had done.

With waterbornes, washing the surface with fresh denatured alcohol is best.

If you want to test you batch, find a piece of clean glass(ask for a scrap at the hradware or glass shop if you don't have any), wash it, wash it again, then wipe it down 3-4 times with fresh alky and clean rags(new rag for every wipe). Immediately brush(using a new, clean foam brush, or drag the finish on using a paper towel) a heavy, wet coat on the glass, and set it aside, with a small box set over it to protect it from stray dust and airborne contaminants. If you have a bad batch, it will have fisheyes once dry. If this dries level and without fisheyes, then your batch is okay, and you had something in your gun, your line, or on the guitar surface itself(or in the shop's air)

Takes but one or two minutes to do this test, and is well worth the effort, with each new jug you open. The same glass can be reused, as the dried finish will scrape off in one shot once dry.