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Corrosion Protection

Greetings Fellow Builders,

I am wondering what RV builders use for corrosion protection?

I am just starting my RV-8 build. My plane will live in a hangar and I am no where near a coast and living in Phoenix, AZ.

On two previous metal airplane builds I have tried/used Zinc Chromate from AC Spruce in their spray cans but too many times I would spray one time and the darn can would clog. I have used aluminum PRIMER purchased from O'Reilly Auto Parts and this seems to apply well but I don't know if it is truly effective to our mission.

Finally, I have never seen so much as a spot of corrosion on aluminum parts on my current plane but that is built almost entirely with 6061-T6 which I have been told has built in corrosion protection not available in the AL that Van's uses. I will admit to not knowing of that is fact or fiction.

Any thoughts and opinions on this topic are very much appreciated.

Steve
 
my take

Many of the brackets on the RV series are made of 6061 and Van's instructions says to prime them regardless of where the plane is planned to reside.

The only option seems to be the Alcad skins which are inherently corrosion resistance.

Many people seem to use the spray can primers. I found the two part primers were worth the extra trouble, but that is just me. I do not know where my plane will be in 10 years, so I am spending the little extra time priming it. JMHO
 
We didn't prime the inside of our RV-8 when we built it 20 years ago (beyond the parts Vans specifies). Our 60 year old biplane at the time had very little corrosion and wasn't even alclad. Dad didn't want the weight or the hassle, and reasoned by the time it did corrode he'd be dead.

Recently I've been doing some work on it and noticed some white spots starting on the inside tops (underneath turtle deck, canopy sills, etc...). Nothing major. I'm going to hit it with some AC50 and move on.

I don't think there is a wrong answer here. The only thing I'd say is that if you elect not to do it commit to an ACF50 bath every couple years. I do it to my Cessna, and other than being a bit messy it's no big deal.

DEM
 
Prime or Alodine

6061 is not alclad and should be treated. 2024 is Alclad. Typically has blue vinyl. Steel is usually powder coated but some is not and should be treated. How you do it and what you use is one of the reasons it's referred to as a Primer war!:D
Personally I think how a part is prepped before application is just as important if not more so. Lots of methods. Every builder has a preference for both.. I used P60G2 and would do it again. It's also Vans choice on QB kits. Very light.
If there were a safe way to Alodine in large volume, it would be my preference. I did Alodine my exterior because I plan to wrap and wanted something light. It was a pain to capture all that rinse water. I used a home made sluce. Tip is in Kitplanes.
I recommend a search, tons of reading. That should narrow down your selection.
 
Guys have been using zinc chromate for years with good results. I decided to use ZC from aircraft spruce at 18$ a can or so, for every part that I won?t be able to see. All joint between ribs and skins, all my spar parts, evewhere between 2 piece of metal.

Total cost, probably 12-15 can for the whole plane.

, I?ll let you know in 60 years how it will be looking! :)
 
Guys have been using zinc chromate for years with good results. I decided to use ZC from aircraft spruce at 18$ a can or so, for every part that I won?t be able to see. All joint between ribs and skins, all my spar parts, evewhere between 2 piece of metal.

Zinc chromate has been outlawed in these parts.

I'm curious if anyone has experience with or opinion on zinc phosphate for a quick sprayable solution:

http://www.aircraftspruce.com/catalog/cspages/zinc.php?clickkey=17411
 
2024 alclad in Arizona is going to be pretty safe with nothing done.

The lightest (virtually zero added weight), and likely least expensive (but more trouble than rattle cans of primer) is, without a doubt, the alodine process. If done correctly, it supplies the same or better corrosion protection than any of the gee-whiz primers you can find, at any price.

There are epoxies that are far tougher, but none with better corrosion protection. Multiple government studies, here and in Europe, to support this. It's in the archives, but will take some digging.

Charlie
 
SW P60G. Cheap, inexpensive, weighs nothing. Same stuff Vans uses on QB's.
While a top coat is recommended, many years and thousands of hours of service has shown it provides very good protection without. It is my choice for Alclad Sheet on the interior surfaces.
I prefer a two part epoxy for bare 2024 or 6061 over the P60G.

I feel this is a balanced compromise between, time, cost, weight, ease, and protection. However, the exterior of mine was acid etched and alodine, primed and top coated (painters preference).
 
P60G2 - Quick question

I found this product on a few sites and the instructions reference mixing the product and the reducer to create a spray-able product.

I am wondering what you guys might be using to apply this? Would you use an industrial sprayer or something like a light airbrush sprayer?

Steve
 
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I found this product on a few sites and the instructions reference mixing the product and the reducer to create a spray-able product.

I am wondering what you guys might be using to apply this? Would you use an industrial sprayer or something like a light airbrush sprayer?

Steve

I used a commercial spray system. You also need to protect yourself with a fresh air breathing system of some type. The biggest mistake folks make is putting it on too thick. It is a wash primer and I believed the specs call for a thickness of only 4 mils, or something like that. When you are done, the finish looks like a subtle greenish tint and slight dullness of the aluminum. The stuff Vans uses is the same but the dye is grayish in color.
Follow the same process as if you where painting anything else. Prep for me was maroon Scotchbrite and Prep-all cleaner then wiped with a wet cloth then air dry.
 
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