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Paint instead of Primer?

cjensen

cjensen

Well Known Member
Well, the subject pretty much says it all, but what's the deal here?

I decided to just paint my seat ribs with regular old Rustoleum Satin White today, and I'm going to continue using regular paint in the cockpit.

My question is, why don't we just use paint instead of primer everywhere? Seems like it would produce a more protective layer than the self-etching primers. I don't know about how the epoxy primers would compare since I don't use them.

What piece am I missing here? :confused:
 
It actually goes like this: We need a film that will look good, seal out moisture and solvents, stand up to UV, inhibit corrosion, and stick to metal. Well as far as I know, they don't make such a product. Paint is designed to stick to primer, not bare metal. It does seal pretty well and look nice, but it is not designed to stop corrosion as some primers are.
 
The Rustoleum (Tremclad in Canada) is designed to adhere to bare metal without primer. The metal needs to be scuffed and cleaned only. In fact, the instructions say so.

I used this product on my engine baffles, which take a lot of abuse and it's holding up extremely well.

If I were to do it again, I'd use it on a lot of small parts where I didn't want to set up my spray gun to shoot catalized primer. I wouldn't use rattle can primer at all, just the Rustoleum/Tremclad when I needed it.

It's not mil-spec, but it sure is convenient. And the grey is almost the same as Van's powder-coat color.

And why not use it instead of primer everywhere? It's heavier and more expensive than a good zinc chromate vinyl wash primer.
 
cjensen said:
Well, the subject pretty much says it all, but what's the deal here?

I decided to just paint my seat ribs with regular old Rustoleum Satin White today, and I'm going to continue using regular paint in the cockpit.

My question is, why don't we just use paint instead of primer everywhere? Seems like it would produce a more protective layer than the self-etching primers. I don't know about how the epoxy primers would compare since I don't use them.

What piece am I missing here? :confused:
Click to expand...

Chad,

Every year for the past four years, Charlie Kuss and I give a weekend workshop on aluminum corrosion protection at Sun n Fun.

This basically consists of etching and Alodining( chromic converting ) the alunimum. I can tell you that if you stable your airplane in a humid salt envirionment like we do in south Florida, the metal will be prone to eight different types of corrosion.. In order to protect against fillform corrosion one must chromic convert the aluminum. Within three hundredd feet of my hangar, there are six Rvs. There areat least three of them are showing corrosion under the topcoat with two years. Which ones, You guessed it.
BTW, there planes are all hangared. One recently was stripped and repainted after two years. Yes , it was alodined this time.

Howerver, seat ribs and the like may survive. In addition I would suggest using a two part milspect strontium chromate epoxy primer.


Peter Laurence
 
plaurence said:
Chad,

Every year for the past four years, Charlie Kuss and I give a weekend workshop on aluminum corrosion protection at Sun n Fun.

This basically consists of etching and Alodining( chromic converting ) the alunimum. I can tell you that if you stable your airplane in a humid salt envirionment like we do in south Florida, the metal will be prone to eight different types of corrosion.. In order to protect against fillform corrosion one must chromic convert the aluminum. Within three hundredd feet of my hangar, there are six Rvs. There areat least three of them are showing corrosion under the topcoat with two years. Which ones, You guessed it.
BTW, there planes are all hangared. One recently was stripped and repainted after two years. Yes , it was alodined this time.

Howerver, seat ribs and the like may survive. In addition I would suggest using a two part milspect strontium chromate epoxy primer.


Peter Laurence
Click to expand...

Hmmm, at least 3 are corroding [sp?]...

That makes me wonder is it the humidity or the salt [or how much of each?]. If someone lives in the humid mid-west but far from the ocean salt how important is it to prime?

Thanks

John
 
Thanks for the suggestions Peter. If I lived in that environment, I CERTAINLY would be priming pretty much everything with an epoxy primer. Here in Illinois, well, we just don't have those types of corrosion issues.
 
Chad, try this..... X-I-M 900 clear coat. Comes in a spray can. Prep with scotch brite and wash with DAWN dish soap. Sprays on milky but dries clear with slight gloss. It's used on aluminum doors. When dry, the part looks great. Try a scratch sample... use the edge of a coin. This stuff is easy and TUFF.

Warren
 
After first doing the clean, etch, AFS prime system, then the clean, etch, alodine, PPG system, I decided to leave as much of the alcad on and let it do it's job. Since then my system is as follows:

1) scuff up surface with Scotchbrite
2) clean surface with MEK (or other surface cleaner)
3) apply a thin coat of Dupli-Color Self Etching Primer
4) apply a final coat of Rust-oleum Gloss protective enamel

Primer01.jpg
 
Ya know, after stripping and painting aircraft from every decade and company that has produced them. I know that the painters that used the old alodine, and etch with zinc primer, helped to preserve the aircraft much more so than the ones that didnt. Usually an airplane that had been painted properly only needs a paint job, because the top coat fades, repairs have happened, or the guy just doesnt like the looks of the old job anymore. On the other hand ones that were not done propperly have paint falling off in sheets, the aluminium looks terrible, holes are often found in tight bends, and around the trailing edge of controls.
If it is in my shop to get painted, it will be Etched, Alodined, and Zinc Chromate primered before any other steps occur!! As we all know, in an airplanes life it will have more than one paint job, i want the airplane to survive long enough for it
 
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