painting aluminum

[norm's tear drop]

Got the al installed and now im ready to paint , any tips and/or pointers on what and what not to do ? May use stage 2 auto paint or may go with paint out of can then clear coat ? undecided as of now ? got 3 estimates 1200 , 500 , 300 from pro painters .there is nothing on my tear drop that exspensive . the highest i have paid for anything on it was 10 foot plywood 3/4 thick was 375 for two peices. caint justify the paint cost of a pro so i might buy a gravity spray gun (60) and stage 2 paint and primer (around 100) or go with a high dollar spray can then clear coat whats the opinions of you great folks on here

PS halfdome i took your advise on the roof yent and it is on the very top of things if you remember our talks

[fromeo]

Norm,

When painting aluminum, I've had good results starting with a self-etching primer.

As for paint application, I'm real good with a spray can (if I must say so myself) but can get a much nicer finish with even a cheap $40 HVLP gun. It's just so much easier to get an even coat and keep a wet edge. The downside is you need clean dry air to run it.

You might want to look into a single stage paint, it's a little easier to deal with than a clear. Most likely you will need different size tips for primer, paint, and clear.

For real low budget jobs I've been known to cut a quart of rust-oleum and spray it through an old conventional gun. Overspray out the wazoo, but it comes out better (and cheaper) than a pile of rattle cans.

Maybe parnold will chime in, he seems to know quite a bit about paint.

- Frank

[parnold]

Avoid aerosols at all costs! You'll regret your choice before too long. If you haven't sprayed with a "real" gun before, I would recommend a single stage paint also. Two stage, or base coat/clear coat gives you twice the opportunity to screw things up.

I second the use of self etch primer, or a well thinned epoxy primer. If you only have money for one spray gun, get a 1.4mm or 1.5mm tip, it's a compromise between a primer gun, and a paint gun.

Overlap each pass by about 50%, and hold the gun perfectly perpendicular to the surface being painted. The first coat does not, and should not cover completely, it's your foundation coat. Depending on temperature, you should apply second coat after about a half hour, the first coat will absorb the second, giving you better adhesion and a little less likelihood of runs. It is an art getting it wet enough to flow out smooth, but not so wet to get runs.

You want to get an acrylic enamel single stage paint, and spend the extra money on the hardener because it also helps gloss as well as offers chemical resistance.

You can check out this site for some ideas of market value..
http://www.paintforcars.com/acrylic_enamel_paint.html

Those prices are very competive, but it looks like you have to buy a gallon. You can paint most sized tears with two quarts. Check some local body shop supply houses, may be cheaper to pay a little higher price for two quarts than buy a whole gallon.

[asianflava]

I worked in a paint shop that did mil-spec paint for some govt contractors. First, we washed all the parts in laquer thinner to remove any oils that came from machining or handling.

We used self etching primers or acid washes on steel parts. For aluminum we would alodine the parts then use a zinc chromate or epoxy primer prior to painting.

[vtx1029]

I'm not a paint guy but worked on aircraft, and they protect the inside skins/frame with zinc chromate primer as talked about above (personally I wouldn't alodine a trailer but its up to u)

[rainjer]

I also work in the aerospace industry. Typically aluminum parts get a acid clean/etch and then boric acid anodize, a chromic acid anodize or a chem-film (alodine) prior to the application of primer. The topcoat is usually polyurethane enamel.

Jeremy

[doug hodder]

I just scuff it well, wipe it down with a degreaser, prime and then paint. How much you scuff it depends on how good the primer is at hiding scratches. If the scratch shows in the primer....it'll show in the paint...I do like 220. If you are new to painting, but have the basic techniques down...I'd just do the single stage. Catalyzed single stage acrylics/urethanes flash off and cure quickly, you can peel tape in like 2 hours...less bugs and dust in them. An oil based enamel, while less $$ takes a longer time to cure and more bugs/dust issues and won't hold up as well as a catalyzed material. PS...A screw up on a 2 stage paint job gets expensive really fast. Others opinions may vary. Doug