Poor storage leads to trouble

So when I put my project on the backburner last year I though I did a pretty good job of putting the parts away and making sure they would be safe for when it was time to build again. I guess I was wrong

I pulled out my leading edge and tank skins still in the brown wrapper and ductape holding everything together. When I looked at the floor I noticed what looked like a damp spot. To my dismay I looked at the brown paper covering the outside tank skin it looked dame and actually had mold on it!

I started to have a feel of dread as i put some gloves and mask on to peel the paper back. At first glance the blue film looked ok. However I noticed the film was slightly raised around the rivet holes. So I started to peel back the film and my fears were comfirmed. Corrosion was around a number of the holes. One hole in particular was worse than the other in that I could actually feel the roughness of the corrosion. The other spots do not look to bad and I don't think I would have a problem scotchbrighting the spots and priming the areas. (All areas are on the outside of the skin, so no priming in the fuel side.)

The good news is that all of the other skins are fine.

What do you guys think? Time to order a new tank skin?

This is the the worst hole.



This one is not deep at all.

Anywhere else maybe okay but the fuel tank? I personally wouldn't take a chance. Relying on proseal versus good aluminum and proseal probably not a wise choice.

Just scuff the corrosion off with a scotchbrite pad, clean it thoroughly and put some alodine on there and you should be good to go. I would not put primer on the interior surfaces of the tank, but alodine should be OK.

As Bruce said, clean the corrosion off with scotch brite and move on. Personally, I wouldn't even alodine it. The hole will be filled with proseal, and the skin will be painted some day. I have bigger patches than this on my bottom wing skins from sweating trying to buck rivets! It will all be removed for paint anyways. After the tank is sealed, you can shoot the affected area with a self etching primer so u can sleep at night.

Yep - this is relatively minor.

There will be plenty of occasions during the build to panic - this is not one of them.

Send the pics to Van's. Get an engineers perspective.

Thanks guys! On a more positive note, I realized it was not the tank skin. It's actually the right side leading edge skin.

let this be a lesson, don't put your project on the back burner again

I think bruce is right, and you can read about filiform corrosion to understand why- it usually has the look of a worm track, and if it hasn't progressed much (yours doesn't look bad at all, that i can see on the photo) it is a very light surface corrosion.

holy shiney worm tracks- want to read 80 pages of discussion of this corrosion on airstreams?


and this thread has one of the best photos of filiform i've seen yet.