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Priming metal / iron parts

oren_rokach

Well Known Member
Hello guys!
We are about to install the flaps and ailerons.
Van's unlike aluminum parts which states "prime if you desire", in this case recommend to prime.
Is the priming process the same? Scotch/scratch, wipe with solvent, alodine and stroncium?

Thanks!
Oren
 
Most (all?) of the steel parts in my RV-9A were powder coated (baked on epoxy) grey or white from the factory.

So, no, the process for steel is not the same as for aluminum. Alodine is specific to aluminum, it is a conversion coating and does not work with steel.

For steel, if it is bare (not powder coated) degrease with a suitable cleaner, scotchbrite to rough up the surface, and epoxy prime. Then topcoat with a suitable paint.
 
Thanks Terry
The parts are powder coated by Vans
I mainly referred to the internal side of the parts.

Mostly tubes , so very hard to reach, scrub and prime in general.
 
An alternative is to run to the store for a shotgun cleaning kit. Clean, lube, and then cap to keep contaminates out.
 
Van's unlike aluminum parts which states "prime if you desire", in this case recommend to prime.
Is the priming process the same? Scotch/scratch, wipe with solvent, alodine and stroncium?

Much simpler! Any self-etching primer with zinc in it will do the duty for a looong time; here's one that's widely available in the States. Rinse tubes with a degreaser (lacquer thinner) and spray away.

I have unpainted repairs to engine mount that have been sitting under a thin layer of zinc primer for most of a decade with no sign of rust. The rest of said engine mount under "high temp" acrylic paint showed light rust after a couple of years already. Epoxy primer can work well if the coverage is 100%--any pinholes will rust. Zinc works sacrificially, so even imperfect coverage will delay rust. There are marine epoxy primers with zinc, best of both worlds but too much work for our needs.
 
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