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Aluminum corrison
- Thread starter glen
- Start date
Vern Klukas
Active Member
The question is whether it is actually corrosion or just the paint falling off. Is it original paint, or a respray? If some of the paint has fallen off, is there any white dust (aluminum corrosion) visible?
Yours
Vern
Yours
Vern
Vern Klukas
Active Member
glen said:Hi the paint has bubled in one or two places. Its not the original paint. No sign of dust.
Glen
Most likely a adhesion problem. A proper fix likely means respraying the entire panels but depending on the paint that was used before it may be repairable. The basic procedure would be knock off the loose paint, then feather back to solidly adhered paint, alodine or etch primer or epoxy primer on the bare metal then the top coat feathered in and buffed out.
Yours
Vern
unstable load
Well-Known Member
We use Alodine first then Plascon Epiwash epoxy primer then paint over for our aircraft.
The Epiwash is great stuff, it dries really hard and adheres well.
The Epiwash is great stuff, it dries really hard and adheres well.
Vern Klukas
Active Member
There are several good ways, but be careful of overkill (all this stuff is expensive now). Way back when, it was alodine (which is an etch, goes on so thin it just tints the metal) + primer plus topcoat. That has evolved to the etch primer products.
Epoxy primer then arrived, and it works well by itself. Alodine + epoxy primer is supposed to be overkill, keeping in mind that epoxy primers are not usually really sandable so you have follow up with a sandable primer anyway. Alodine + etch primer is wasting the alodine to my mind.
The bottom line, though, is it's hard to get paint to stick to aluminum. Even using one of the above, you can still have failures particularly on aluminum where you've already had the paint fail. You have to get the metal really, really clean before you start applying your coatings, and alodine and epoxy may be the safest option.
Yours
Vern
Epoxy primer then arrived, and it works well by itself. Alodine + epoxy primer is supposed to be overkill, keeping in mind that epoxy primers are not usually really sandable so you have follow up with a sandable primer anyway. Alodine + etch primer is wasting the alodine to my mind.
The bottom line, though, is it's hard to get paint to stick to aluminum. Even using one of the above, you can still have failures particularly on aluminum where you've already had the paint fail. You have to get the metal really, really clean before you start applying your coatings, and alodine and epoxy may be the safest option.
Yours
Vern
unstable load
Well-Known Member
[quote="Vern Klukas" Alodine + epoxy primer is supposed to be overkill, keeping in mind that epoxy primers are not usually really sandable so you have follow up with a sandable primer anyway.[/quote]
We fly offshore, so the paint needs to be sound and solid.
A quick rub with a Scotchbrite pad is all the prep you need between coats.
On panels that need minor cosmetic work, I'd prime first then fill/filler prime.
We fly offshore, so the paint needs to be sound and solid.
A quick rub with a Scotchbrite pad is all the prep you need between coats.
On panels that need minor cosmetic work, I'd prime first then fill/filler prime.
Vern Klukas
Active Member
unstable load said:We fly offshore, so the paint needs to be sound and solid.Vern Klukas said:Alodine + epoxy primer is supposed to be overkill, keeping in mind that epoxy primers are not usually really sandable so you have follow up with a sandable primer anyway.
A quick rub with a Scotchbrite pad is all the prep you need between coats.
On panels that need minor cosmetic work, I'd prime first then fill/filler prime.
Overkill for cars, I should of said. I used to do boats, same sort of deal there for aluminum topsides & masts. Except epoxy primer wasn't as well developed then (hate to say it, 30 years ago) and we found our best results were following the epoxy asap with the topcoat or fairing materials. If we let it cure and tried scuffing it, the topcoat would start to fall off is just a few months as often as not. It's better now, of course.
Yours
Vern