Alumiprep & Alodine but no Primer

EAA as a help for homebuilders video showing using Alumiprep and Alodine on a small part: http://www.eaavideo.org/video.aspx?v=1340416082001

The video indicates that this process provides siginificant corrosion protection, even without additional priming. Plus, it maintains electrical conductivity and adds no weight or size changes to parts. After a bit more internet research, it seems that it is possible use a brush or sponge with water-rinse to do these two steps for larger parts. Perhaps this might be a good alternative to rattle-can priming.

Any thoughts or experiences to report?

That's the way I have been shown in my A&P classes and that's the way I do it for most of my RV9A parts... but I add one light coat of primer on top of it because the Alodine protection is easily scratch and because that's the way most of the biggest certified airplanes are done and it's the way I have been taught to do it!
Yes it takes more time to do but I feel like it's the best protection you can provide, being that where I live, the airplanes go through ruff condition from -40oC winter with snow to +40 in high humidity during the summer!

First, I usually stay off the subject of priming.
I live in Ohio and have worked on old airplanes
with still good looking bare interiors. Coastal
areas may need more protection.
If someone wants to prime everything, go for it.


With that said, we have used the procedure
stated in the EAA video for years on replacement
skins on repairs to Luscombes, etc.

On my RV before assembly, we used acid etch with
a scotchbrite pad on the interior side of the skins.
You can tell when it is ready for Alodine
by the way the water sheets easily off the aluminum.
This is followed immediately by applying the
Alodine with a sponge, waiting three minutes,
rinsing it off with water and then let it air dry
without touching the surface. The exterior sides were
etched and alodined when the RV was painted.

We did lightly prime faying surfaces, angle and some
other parts before assembly with an etching primer.

I think an RV will hold up with this procedure,
Tom