Pan corrosion?

[IslandLife]

I’m sure that someone has come across this but I couldn’t find any threads on the topic. It’s between the crossmembers of the frame and not in direct contact with the frame in the area if corrosion. It is just in front of where the fresh water tank was. I’d like to figure out what happened to prevent it from happening again. Thanks in advance!

Ken

[Kevin245]

Appears to be galvanic corrosion (GC). It can be minimized by coating the materials to prevent direct contact. There is always the potential of GC when dealing with dissimilar metals.

[IslandLife]

Originally Posted by Kevin245

Appears to be galvanic corrosion (GC). It can be minimized by coating the materials to prevent direct contact. There is always the potential of GC when dealing with dissimilar metals.

Thanks Kevin,

From the look of the edges, it does appear to be galvanic corrosion of some sort. Though the area of corrosion was not contacting the metal frame. It may have been the copper propane lines (no longer there). From the little bit that I've read, steel in contact with aluminum isn't nearly as corrosive as copper is to aluminum. This trailer also spent some time near the ocean in a high humidity/salty environment. So that would have likely sped up the process.

I'll read up more on galvanic corrosion. I've previously had a welded aluminum boat, and sacrificial zinc anodes are used extensively to protect the aluminum.

Ken

[Wabbiteer]

Where in relation to that is the propane lines run outside the pan?

I'd be curious to see what the outside vs. interior patterns are.

I've seen aluminum outlive the iron it was sistered in next to - yes the Aluminum is weakened and white with oxide but the iron went to lace with missing sections.

[IslandLife]

Definitely in the vicinity of the copper propane line. And seeing how it was only held by a string for who knows how long, I suspect that it was contacting the pan on a regular basis. No rubber mounting brackets at all on the forward half.

[A W Warn]

My guess is the aluminum was exposed to road salt for years without being washed.

[dznf0g]

Or....our airstreams never have assembly scraps of schtuff just sitting around...everywhere, right. Steel scraps+ aluminum+water +time=galvanic degradation. Perhaps.

[IslandLife]

I did manage to get under it completely today and found the pan was overall in decent shape. At least better than I had expected. I wasn’t able to get under it completely before I bought it, and I was expecting it to be worse. Other than the main cluster of corrosion, there were only a few other spots. So I’ll patch it and seal it up.

This trailer will spend at least the next couple of years parked on my property as a cabin. I just want to make sure that the mice and such don’t have easy access to the belly of the trailer.