Is there any direct to metal paint system in use in GA?

I have no idea how many hours I have used “researching” into paint and primers. What I ended up with is a combination of polishing the bare metal, and using an industrial paint ment for marine conditions. The industrial paint is one single layer of Power Coat. The default non glossy finish matches very nicely with the very high glossy polished areas.

There really is only one single correct way to paint aluminium in aircraft. That is Alodine treatment of the metal, then a chromated epoxy primer, followed with PU top coat. That will last for centuries. Alodine is a strong anti corrosive in itself, but the main point is that it creates a chemical bond with the aluminum. During the alodine treatment, the natural oxidation layer is removed, and replaced by a chromated, sticky layer, chemically bonded to the bare metal. That layer fuses with the epoxy primer, which again fuses with the PU top coat. It’s all thin and light and extremely durable. Although the top coat tends to be way thicker than necessary, for cosmetic reasons I guess in most aircraft.

The down side of the correct approach is those chemicals and the process is very toxic and messy. Alodine is prohibited most places, also industrially. The process is very complex and complicated, time consuming and expensive.

There are many alternatives to the correct process. None are nearly as good, still they are good enough for light GA. Polishing, polish every year, and the metal is protected for centuries. The only downside is you have to polish every year, or it will look bad The paint I use, is a one coat system. It is single component and certified according to DIN and NORSOK to protect metal more than 15 years on extreme marine conditions (North Sea). For me, it is non toxic and easy to apply, and found in industrial stores everywhere.

The Alodine problem is a thing to take note of. With no alodine, the primer will not be chemically bounded to the metal. The way around that, is to buff the metal with scotch brite, and immediately apply the primer. If it stay for longer than 8 hours, un-primed, you have to buff it again. The buffing does two things, it creates a surface for the paint to stick better, and it removes the oxide layer that virtually nothing sticks to (therefor max 8 hours, or the oxide layer will grow too thick). Some specifications prescribe acid wash just prior to painting, while another way is to use acid etch primer. Some of those systems will also create a kind of quasi chemical bond, but without chromated agents (it’s not really a chemical bond I believe, it’s more that the paint is in direct contact with the metal, because the acid cracks up the oxide layer)

Another thing is whatever method you use, be sure to follow the recipe from the manufacturer (correct equipment, correct thickness etc). The paints are systems meant to work together, you should not use a primer from one manufacturer and a top coat from another for instance.

What I do is to scoth brite the surface, clean with cilicone remover, then paint immediately, one single coat using Power Coat rattle can. Couldn’t be simpler, and guaranteed (certified actually) to last for 15+ years in normal atmospheric condition. One coat is approximately 50-60 my, which is way less than a typical PU painted aircraft. I can also use a special clearcoat on top to make it glossy and more durable, but it will weigh more, and doesn’t really look as good in contrast to the polished aliminium.

Peter wrote:

Does this mean no paint shop in Europe will alodine the airframe?

Alodine can be bought. But if someone use it commercially? I really don’t know, I would guess the cost of handling the spills (highly toxic and environmentally disastrous) would severely limit it’s use, at least openly. Airliners are stripped and re-painted every 5-10 years, I can’t image they would use it anymore, but who knows?

Great information in this post.
I’m looking to do some touch-ups and am brand-new to the world.

Today I was going to paint the Austrian Flag on the tail… I had everything taped off and prepped, and just couldn’t take the spray can and spray it on my tail. I couldn’t do it.
I was too nervous that I was doing something wrong.

Well, after reading this, it is clear that it wouldn’t hurt anything, because I’m spraying on top of existing paint, but certainly, I’d just be scraping it off and doing it again in about 2 months… (crap paint from a hw store…)

I’m now setting about to try and find some JS Cock PowerCoat 3-in-1…

Thanks a lot for this golden thread!

UPDATE: Well… JS Cock is apparently a product only available in Norway…
Any suitable alternatives I might be able to find in the German speaking world?

I would never paint the flag on but rather use a decal. If you can’t find the right size – any car foil / advertising shop can print it for you.

AF wrote:

Today I was going to paint the Austrian Flag on the tail… I had everything taped off and prepped, and just couldn’t take the spray can and spray it on my tail. I couldn’t do it.

might be a good idea not to. Get a decal. Much easier to get rid of.

Austrian flag, why? You sound very American to me, do you actually live in Austria?

Alexis wrote:

rather use a decal.

Mooney_Driver wrote:

Get a decal

Thanks for the advice guys.
Unfortunately, there is a flag already painted on there and I was just going to paint over it…
I had initially bought a decal, but the flag that is already there is kind of slanted (angled sides) which would
a) make it hard to cover
b) would be hard to apply a decal to, simply because of the uneven surface of the Mooney tail at that location.

Mooney_Driver wrote:

Austrian flag, why? You sound very American to me, do you actually live in Austria?

Yes, I’m American and I live in NiederOesterreich (notice the lack of an O with an Umlaut? That’s me being a cheapo and buying computers in the US… )
I’ve lived here for 5 years, aber mein Deutsch ist noch unglaublich schlecht… :(
Ja, so ein Amerikaner in Oesterreich bin ich eigentlich.

Liebe Greusse und ich freue mich euch (Sie?) kennen zu lernen.

Liebe Greusse und ich freue mich euch (Sie?) kennen zu lernen

Euch ist richtig weil du mehrere Leute ansprichst und sich Flieger alle duzen

Liebe Grüße nach Niederösterreich!

AF wrote:

Yes, I’m American and I live in NiederOesterreich (notice the lack of an O with an Umlaut? That’s me being a cheapo and buying computers in the US… )
I’ve lived here for 5 years, aber mein Deutsch ist noch unglaublich schlecht… :(
Ja, so ein Amerikaner in Oesterreich bin ich eigentlich.

Liebe Greusse und ich freue mich euch (Sie?) kennen zu lernen.

You know that, with a Mac at least, pressing and holding the alt and u keys together gets you the umlauts? So to type ö, you just hit the following keys:

ALT + U together
O

Sorted ;-)