The International Cessna^® 170 Association

counsellj wrote:Photos?

I will resize my photos and try to get them on tonight. After removal of the tank in the right wing I found two rivet heads corroded of on the forward half of the rear spar attach point. Drilled them out last night and the spar attach plates on the wing side of the rear attach point are corroded beyond safety. The forward carry through spar if fine, but the forward plate on the right side "A" pillar door post is corroded pretty badly, where it attached to the forward carry through spar. My plan is to replace every rivet in all four wing attach points and both carry through spars where they attach to the airframe. Also found a manufacturing booboo in the right wing front attach point, I will post a picture of that as well.

Thank you for taking the time and dealing with the hassle to post the photos. I lot of other owners can learn from these.

Cabin roof skin and front carry through spar removed

Some more pictures

Thanks for the photos. Surprising to see that sort of corrosion on an Arizona plane. I'm guessing it was based near the coast in the past.

Corrosion is caused by more than the storage-environment of the home-field.
Airplanes flown in rain, or humid destinations,....wash-jobs... ...leaving the ground, going up to altitude, descending back through temperature-levels for 60 years....with moisture-exhaling occupants... creates condensation...which in partnership with dust/dirt/soaps/time.... all contribute.

Inspect, Inspect, Inspect.

George, what percentage of time does a plane fly in relation to sitting parked at home base? Answer: Around .8 % of the time for a 4000 hour airframe that is 60 years old.

These corrosion photos are the ones I'll be showing the wife when I try to justify hangar rent.

Hangars don't prevent corrosion. In fact, they can speed it up if they don't have good ventilation in them.
They're also attractive homes for mice.

Hangars prolong the time between coats of wax and do a fair job of preventing hail damage tho.

Obviously the affordability of a hangar varies based on location which in some areas makes hangaring a tough pill to swallow but I would hangar every time. We haven't mentioned UV damage, but next to corrosion there's another thing that eats away at our investments.
Nothing will stop corrosion, all you can do is try to control the rate.
Unfortunately for the owner based on the pics this aircraft is about to undergo a fairly extensive repair. The pictures shown so far certainly don't suggest its a dry country plane. Might be interesting to see the inside of the wings.

n2582d wrote:George, what percentage of time does a plane fly in relation to sitting parked at home base? Answer: Around .8 % of the time for a 4000 hour airframe that is 60 years old.

These corrosion photos are the ones I'll be showing the wife when I try to justify hangar rent.

It's the ...TIME...coupled with contaminates and electrolyte/moisture ...that is the essential ingredient of most corrosion.

Hangars are good anti-rain, anti-hail, anti-wind, anti-theft, anti-sun... but anti-corrosion? Not necessarily.* A buddy I know installed a drain in the center of his hangar thinking it'd be a good place to wash. He stored his car and his boat in there too. It was heated with a natural-gas furnace (which produced water vapor presumeably because it burned fossil fuel.) The entire interior was a moldy, humid, rusty shell. He was over 100 miles from the coast.

*Keeping it out of the rain, wind (dirt accumulations), and sun slows down corrosion, but it won't guarantee no corrosion.

Wash it using WD-40 as a surfactant instead of soap in the wash-water. It'll lubricate hinges, weatherseals, keep paint rejuvenated, and will penetrate lap-joints to work against corrosion-inviting moisture. Soap is alkaline and will remove lubricants and attract moisture.

George, complete your WD-40 recommendation for washing our planes by repeating the ratio of WD-40 / water.

The exact specifications of the recipie is critical!

(A few cups of WD-40 to a 5 gallon bucket filled about 2/3rds under the force of a garden nozzle. I buy WD-40 in gallon cans.)

Rinse the dust off the airplane with a hose, mop it down with the WD-40 solution using a dedicated cotton mop and old towels used only for plane washing, rinse with the hose again, and dry with old cotton towels.

WD-40 in a spray-bottle is also very good with which to wipe the belly down between flights, laying on a creeper and a roll of paper towels. A squirt or two onto the tailwheel spring-set/tailwheel, then scrubbed with a car-wash tire-brush, and a rinse with the hose will keep the tailwheel in show-condition.

WD-40 does not hurt plastic (windshields) or rubber but I don't deliberately apply it there. The little that gets there accidentally just does no harm. I use a good windshield cleaner like Davis, Prist, etc.. and do not use or recommend Pledge (and I absolutely condemn Simple Green in any flavor including their "aircraft" stuff, which anodizes/stains aluminum.)

I did a complete corrosion proofing of my entire belly all the way to the tailwheel yesterday. Not an approved method though, and hate to admit the process ( reminder to me: don't answer the cell phone as you just finish adding a quart of oil... glad the oil cap has a chain on it...)

I have been doing a 26 year test of pledge on the windshield though, still looks as good as any that I've seen...

Joe

Joe, rest assured you aren't the first nor will you be the last to forget to replace the oil filler cap. It happened to me twice within 6 months several years ago Sure makes a mess Fortunately our filler is behind the pressure bulkhead so we don't get the suction that the larger bore Continentals do. I understand they will suck out most of the oil in a fairely short time. The first time I forgot (got distracted) I flew for over 3 hours with the cap off and the tail wheel springs got a good lubercating. As I seem to recall that I only lost less than 1/2 a quart.

gahorn wrote:Corrosion is caused by more than the storage-environment of the home-field.
Airplanes flown in rain, or humid destinations,....wash-jobs... ...leaving the ground, going up to altitude, descending back through temperature-levels for 60 years....with moisture-exhaling occupants... creates condensation...which in partnership with dust/dirt/soaps/time.... all contribute.

Inspect, Inspect, Inspect.

Bingo!!