Tip: Beware Corrosion!

ratc · #1 06-15-2006, 11:42 PM

For those who are hard at work building and doing all the right things - like protecting the surface of material by leaving the plastic film on. Think about the long term. Don't delay taking off the protective plastic film ASAP and prime/treat.
Yes, you will have to be a little more careful about how you handle the material but that is in your hands. Corrosion is indiscriminate and can creep up from behind and bite you when you least expect it.

Perhaps it's mishandling or the environment it was stored in but this is the result after 9 months stored in a box. The total age of the kit 18 months!

Now it's a case of Deoxidine, alodine, prime and always the nagging thought that you didn't get it all.

What size photographs are the best?

chaskuss · #2 06-16-2006, 08:00 AM

Andy,
I live in SE Florida. I doubt that there are any environments more humid than here. That said, I left the plastic on all my parts for the duration. I only removed the plastic on the rivet lines during deburring and dimpling. I had no corrosion problems.
I think that a lot of the problems with corrosion under the plastic have more to do with how you store the aluminum parts. Wooden boxes and the heavy paper cushioning that Vans uses, act like a sponge. They absorb moisture and hold it in contact with any metal which touches them.
Take your parts out of the wooden or cardboard boxes. Do not leave them laying on concrete floors either.
Charlie Kuss

thallock · #3 06-16-2006, 11:42 AM

Andy,

What is your concern here? All I see is a few extremely minor spots, which will be gone once you prep your skins for painting. You could have easily seen the same without the plastic on.

Tracy.

rv9builder · #4 06-16-2006, 01:48 PM

I live in Southern California and my kit is inland from the ocean about 50 miles. I recently discovered very light corrosion on several of my fuselage skins that were riveted into place last summer when it was extremely hot (over 100 degrees F). The plastic had been removed from the skins. I guess the sweat from my hands while I was working on the skins must have caused the corrosion. I thought the alclad would have protected the aluminum.

ratc · #5 06-17-2006, 08:05 AM

Tracy - Perhaps I'm missing something here. Is corrosion something NOT

to be concerned about in any form?
Mark - like you I was under the impression that ALCAD was supposed to combat corrosion. At least for a "reasonable" time.
Please correct me if I'm wrong.

thallock · #6 06-19-2006, 07:54 AM

Andy,

Nope, that amount of corrosion is nothing to be concerned about. This small amount of corrosion will be removed with the normal preparation that is required for painting. If the surface is going to be left unpainted, then maybe I would be a little concerned, since there will be a slight discoloration that would need to be rubbed out. I have no idea how this would look on an unpainted aircraft, but I suspect that if this would ruin a polished aluminum surface, then there would be no polished aluminum airplanes.

Tracy.

Jamie · #7 06-19-2006, 08:13 AM

Bare alcad will oxidize and change color. Looks to me like the discoloration streaks that were under the plastic coating are the same color as the aclad where the rivet lines were.

This is why I think removing the vinyl with a soldering iron is a complete waste of time. If you're going to polish the plane, you're going to have this discoloration. I've seen it on many RVs. If you're going to paint, you'll be sanding/etching the surface anyway, so who cares if you have a little scratch here and there?