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Any spray painters out there? I'm pulling my hair out here!

I finally got the clear coat from the T-bird sport hub stripped and had the hub polished to get rid of all the "white rust". Everyone I asked about clear coating it said "just go buy a spray can of clear and do it yourself" so I did.

Five times.

The first three times it came up looking all "frosty" with a rough finish - interesting effect but not what I wanted. The fourth time it came up almost perfectly clear, except for the odd white "blotch" which looked like I'd put it on a bit too thick there. Waited for the blotches to go clear but they didn't so I cleaned it off and tried a fifth time, where it went all frosty again.

Each time I'm cleaning the clear off with turpentine and then cleaning that with an old t-shirt and lots of elbow grease. The clear is a quick dry enamel (according to the can). Every time it's been frosty I did the whole "several thin coats" thing, and the non-frosty time I went for a few thick coats instead. I'm giving up and paying someone else to do it for me now, but for future reference what was I doing wrong?

When I rattle canned a clear coat I used acrylic enamel and applied three coats in succession allowing each to tack up for around 15 minutes and applying a heavier coat at each pass. Then it cured for a week and I smoothed it by wet sanding with 1200 grit paper that had soaked overnight in water with a couple of drops of soap detergent for lubrication. Final polishing was Meguiars Swirl remover applied with their $15 lightest cut foam pad mounted on a 600 rpm hand drill.
The problem as Isee it with straight enamel is that is doesn't contain enough solvent to melt into the previous coat giving a dull translucent appearance instead of clear, that's why lacquer is so popular and also hard to apply. Acrylic enamel seems to bridge the gap, at least it did in my case.

What is the moisture in the air like there? Sometimes that can cause the clouding of the clear. Enamels are especially susceptible to that problem.

I would have tried some kind of polyurethane.

Soren

err well this is Queensland in late spring so the humidity's around 70% at least but I did it at night so the temp was down to about 25C/77F. It was raining lightly too.

I should probably point out that I don't know an enamel from an acrylic from a polythingy... I just grabbed a can that said "clear".

Talk to your local autoparts store that carries automotive paint. You might want to go with a real automotive urethane clear. Or maybe go to a body shop and ask them to spray it next time they're clearing a car. Or have it powdercoated clear.

Matt, Soren is right... due to the high humidity levels you could have been experiencing blushing. The coating flashes off/skins over so fast that moisture is trapped underneath it. Another contributing problem could be the turpentine leaving behind a residue even though you think you cleaned it really well. Turp is a bit too "oily" to use as a cleaner.
If you want to clearcoat metal I highly reccomend you have it powdercoated.. powdercoating is not porous so it holds up far superior to other coatings. Lacquers and enamels break down after a few years or quicker depending on weathering and such. This lets the elements in (read water/rain) and causes the underlying surface to start oxidizing. If you want to go a rattle can route on clearcoating I would highly, no ONLY recommend Permalac . This stuff is the shizzle and holds up better than any other stuff I have tried. According to their website you can find it there in Oz.

Soren, John,and Steve are all correct. Powdercoating is best. However, if you want to spray clear you MUST use 2 part polyurethane especially for a hub (don't want to take that back apart). Best idea is to have someone shoot it while they're clearcoating something else. Cleaning anything before paint can be done with brake cleaner if no reducer is available. Clean-up is the toughest part when painting small items, I clean my gun with carb cleaner then brake cleaner.

the spots are nasty stuff under the clear on the paint.. Remember a good paint job is not in the paint but in the prep.. Make sure you have high quality paint, mositure free air supply, a clean surface to be painted, and humidty levels are with in spec for the paint. If you call the supply house where you got the paint, they can supply you with that info..

20 years of painting, I still remember a thing or two.

Soren