flyrotary@lancaironline.net Mailing List Archive

Jeff,

When I started building the RV I went the etch, alodine, prime route with PPG DP series epoxy primers. Thats whats in the tail feathers. Too much work. For the balance of the airframe I figured if the SW wash primer was good enough for Vans its good enough for me and thats what I used for the most part. For little odds and ends pieces I used a self etching primer in a rattle can that I picked up at my local auto body supply shop.

Having said all of that if I were building an RV today I wouldnt prime any of the Alclad surfaces, only the 6061. While I was in the process of finishing up the airframe construction of the RV I bought into a partnership on a 1947 Cessna 140. I was pretty involved in the annuals and general maintenance of that airplane. The inside of the fuselage was bare 2024T3 just like the RV and there was very little corrosion in it. I now realize that the Alclad will pretty likely outlast my medical eligibility.

Mike Wills

RV-4 N144MW

----- Original Message -----

From: Jeff Luckey

To: Rotary motors in aircraft

Sent: Friday, July 24, 2009 3:10 PM

Subject: [FlyRotary] Primers & Priming

Please forgive me if I already asked this question here and I realize that this is not engine-specific but…

What are builders of aluminum airplanes doing about priming? The last time I did any serious painting was a long time ago. Way back then, the standard practice for aluminum was to clean, acid etch, alodine, then prime w/ zinc chromate. From what I’ve read, a lot has changed since then.

I’m getting ready to put rivets in tail feathers and feel the need to prime interior surfaces. The airplane will most likely be tied down at an airport that is less than 2 miles from the ocean so I think I will need very good corrosion protection. Some products I’m considering:

ACID 8 self-etching primer – comes highly recommended by auto guys, but it doesn’t have much of a track record in airplanes
Stits EP-420 epoxy primer
The Sherwin Williams primer that Vans uses

If you have used any of these products or have a better idea, I’d really like to hear about it.

Thanks,

Jeff

(If you think this subject is too far off-topic please reply to me privately)