Unusual paint failure related to fuel leak

[Fearless Tower]

Discovered this on the Baron while preflighting. Further investigation revealed leaking gascolator on the right engine. It appears the fuel that was leaking followed the seems of the inner landing gear door and the paint is failing all along those edges.

Has anyone ever seen this kind of paint failure? Pair job is a little over 10 years old I believe.

We solved the leak problem, but now wondering what the best way is to address the paint and metal affected.

 

[bnt83]

Discovered this on the Baron while preflighting. Further investigation revealed leaking gascolator on the right engine. It appears the fuel that was leaking followed the seems of the inner landing gear door and the paint is failing all along those edges.

Has anyone ever seen this kind of paint failure? Pair job is a little over 10 years old I believe.

We solved the leak problem, but now wondering what the best way is to address the paint and metal affected.

What was used to paint it? Many aren't fuel proof.

 

[Subsea]

Mogas or pure avgas? I've seen mogas destroy some good paint jobs. I have yet to see avgas do the same (or is this the first?).

 

[kgruber]

Paint shop for a touch up. Do all the other area at the same time.

 

[Anticept]

Fuel has additives that slowly eat paint up, like toluene. This is very typical.

 

[bnt83]

The maintenance manual for mine shows it was painted with acrylic lacquer (its 47 years old, never been repainted) and I really jacked the paint up when I did the following:

#1 Topped the fuel tanks after flying

#2 A couple days later I got my freshly painted nose wheel fairings so I promptly tied the tail down and pulled the nose wheel

#3 Having trouble fitting the nose pant, I left the nose up in the air overnight to finish it the next day.

Gas had wept out the fuel caps all the way aft to the trailing edge of the flaps then dripped down the side of the fuselage and screwed the paint up the whole f***** way.

I'm still disappointed. The paint isn't great anyway but wings were pretty good till that happed.

These shiny parts are constant reminder of me screwing up the paint on the wings.

 

[Fearless Tower]

Mogas or pure avgas? I've seen mogas destroy some good paint jobs. I have yet to see avgas do the same (or is this the first?).

Pure avgas.

Not sure if it had an effect, but we replaced the bladders on that side two months ago. Fuel samples still dark from the inner coating of the bladders. Not sure if that made a difference.

We looked in the logs. Turns out the paint was 1994, older than I thought. It says zinc chromate primer, and I believe DuPont paint. Closer inspection seems to show that the fuel is reacting with the primer and not the paint itself. It is happening along the edge of the gear door, where the paint has had a lot of wear/exposing primer.

 

[Fearless Tower]

Fuel has additives that slowly eat paint up, like toluene. This is very typical.

This didn't happen slowly. It just appeared over the last week. We did a preflight last week and it was not like that.

 

[Henning]

This didn't happen slowly. It just appeared over the last week. We did a preflight last week and it was not like that.

Aluminum hates paint to begin with, add anything to the equation that can weaken the bond and it's over. The best thing is remove the door and strip it. On the adjacent surfaces I would carefully remove the paint with a well honed draw scraper then carefully feather the edge with some wet/dry 220 or 320 and soapy water staying off the Alclad as much as possible then blend fresh paint over the area and reprinting the door then reassembling. If you want to file an insurance claim, the paint damage is covered.

 

[bnt83]

Aluminum hates paint to begin with, add anything to the equation that can weaken the bond and it's over. The best thing is remove the door and strip it. On the adjacent surfaces I would carefully remove the paint with a well honed draw scraper then carefully feather the edge with some wet/dry 220 or 320 and soapy water staying off the Alclad as much as possible then blend fresh paint over the area and reprinting the door then reassembling. If you want to file an insurance claim, the paint damage is covered.

I was stripping door jams last week with MEK, took the paint off pretty well but didn't do much to the yellow primer (or the filler) underneath. I would assume that is the real deal zinc chromate from the 1960-1970