How common is corrosion on these old birds (Cessna 170/180)? The older 172 I am currently flying is constantly battling corrosion but we are near the coast in a high humidity environment. The plane is hangared daily in a fully enclosed hangar but there's no avoiding the salty air here near the gulf coast.

Once you have corrosion is it possible to defeat it or will you always be battling it even after a full repaint with proper prep work prior? And lastly, how much corrosion is too much when shopping for a used plane?

Always a Battle. Has to be a bit of floatplane action where u are. Research what the major seaplane operations do to stay on top of (battle) it . My airplane came from Hawaii . I do the full fog treatment every couple years when it’s all torn down for annual. Find a real good mechanic that doesn’t mess around and actually knows where and what to look for.I think different people will have different tolerance’s for how much corrosion they are willing to deal with…. Lots of airplanes have some form of corrosion somewhere.

CoaSTOL Cowboy wrote:...Once you have corrosion...

IMHO, it's best just to start with an airplane with no corrosion. Corrosion where you can "see" it isnt usually the problem, its where you "can't" that's worse.

I grew up in New England. I thought rust repair was normal whilst restoring trucks and cars... until I moved to CA, and then realized those guys just got right to the fun stuff. There's no reward in busting knuckles and fighting corrosion. There are plenty of airframes that have no issues... so spending time and $$$ on the more interesting stuff is much more appealing.

Running these plans in a coastal environment is just an ongoing battle with corrosion. We do the various oily sprays for prevention, until it leaks out the seams of the plane. Even with that we still figure on doing replacement panels from time to time, particularly at the tail. We're always watching for little corrosion spots and jumping on them, stripping them down to bare metal then alodine, primer, repaint. We're doing float flying on the ocean though.

Good feedback, thanks!

My 54 180 had surface corrosion when I got it in 1988. For some reason it was where someone had glued insulation to the inner skin and bulkhead back around the rear of the headliner. It was not that it actually got wet either but seemed the glue was the culprit. I scrubbed with scotch bright did the acid etch and alodine and then sprayed ACF-50 all around. It creeps between skin laps well and solved the corrosion problem.

Location location location

Hot humid coastal is the worst
Coastal isn’t good

I think pratt has a corrosion table of the US showing where it’s a bigger concern per how often to do a engine wash