Thorp Air Command - T18.net
http://thorp18.com/thorpforum/

Priming interior airframe parts
http://thorp18.com/thorpforum/viewtopic.php?f=22&t=9149		 Page 1 of 1
Author:  flyingfool [ Mon Aug 18, 2025 4:23 pm ]
Post subject:  Priming interior airframe parts
I recently joined the Vans RV Airforce forum to help learn some building techniques etc.

One thing is there is some sort of major "deal" with paint primers. They call it the primer wars. As a newbie there I didn't want to start a huge Hatfield and McCoy's feud.

Anyhow I am wondering how simple and inexpensive can I be for priming the interior wing and airframe parts that no one will generally ever see. I know that two part epoxy is the gold standard it seems. But all I am looking for is some corrosion protection for interior wing ribs and components. Primer between places where two parts are riveted together etc. the under side of wing and fuselage skins etc.

Can I use some big box store rattle can primer/paint? Since no one will generally see it other than for maintenance. It doesn't have to be pretty or perfect paint application. But I would like it to be a fairly light color like white or gray or light green. Does it have to be self-etching primer?

I read that epoxy or other top coatings do not like to stick to the self etching primer due to the acid in it that does the etching.

The exterior of the plane will be "proper" primer and paint top coat. Probably done by someone who knows what they are doing with spray painting aircraft!
Author:  Ryan Allen [ Mon Aug 18, 2025 5:45 pm ]
Post subject:  Re: Priming interior airframe parts
I am interested to see the responses to this. I am a newbie as well. I have no idea if what I summarize below is correct, but its what I do. I, like you, dont plan to apply primer to any surface that will be painted by a professional later. I have used both Rustoleum rattle can self etching primer and 2 part epoxy primer I get from my friendly local car paint shop. I think you need self etching rattle can for better adhesion to the part.

I have come to to adopt the following practice: If its a truly hidden part, or mating surface, or somewhere that will see very minimal "wear and tear" I use rattle can self etching. I think the key is not to spray the rattle can primer too thick or it will tend to flake off. If I want to prime a part that will see more "wear and tear" (think around the cockpit area or baggage area), I use the 2 part epoxy primer. I think the 2 part is more durable, but I have some angle that I have sprayed with rattle can primer that is really well adhered. I always hit the part with the maroon scotchbrite pad, then clean it with MEK prior to applying either type of primer.

Again, I have no idea if this is right, so hopefully some more experienced builders will chime in.
Author:  isyncro [ Mon Aug 18, 2025 5:49 pm ]
Post subject:  Re: Priming interior airframe parts
Hope that helps....
https://www.youtube.com/watch?v=JlhzQRO ... aK&index=8

Image
Author:  flyingfool [ Tue Aug 19, 2025 10:53 am ]
Post subject:  Re: Priming interior airframe parts
Thanks for the youtube video. That helps. Has anyone else had good success with his method? Seems straight forward enough.

I have read a lot about use of various color scotchbright pad or similar with one of the prep stages. Some say with the washing cleaning stage, others as a separate abrasive rub and water wash before priming.

maybe there is no "right" answer. But I for sure want to avoid the for sure wrong things to do.
Page 1 of 1 All times are UTC - 6 hours [ DST ]
Powered by phpBB® Forum Software © phpBB Group
https://www.phpbb.com/