Aircraft Metal Degradation

PhantomAce08 · **Posted:** Wed Apr 08, 2009 11:11 pm

Does anyone have any information as to how aircraft are treated once they are recovered from water? Is there any treatment to the metal? Is there any issues with the metal once it is brought out of water?

I have to do a research project for college and my major is Chemical Engineering. I thought it would be cool to do something related to aircraft somehow. Any suggestions would be great!

Thanks.

-Nathan

bdk · **Joined:** Sun May 02, 2004 1:16 am **Posts:** 11336

I recall a thread on this here a year or two ago. You might want to do a search.

Mgawa · **Posted:** Thu Apr 09, 2009 12:16 am

Most efective is the bath in the epoxy resin solution.

SHAEF1944 · **Posted:** Thu Apr 09, 2009 1:32 am

HTML version of a PDF file : restoration of an Oscar

http://74.125.93.104/search?q=cache:qS6 ... s&ie=UTF-8

SHAEF1944 · **Posted:** Thu Apr 09, 2009 1:41 am

Another read that may be helpful

http://www.museum.wa.gov.au/collections ... ewulf.html

JDK · **Posted:** Thu Apr 09, 2009 2:04 am

Neato!

It 'ain't just water, it's salt or fresh - a critical distinction. Very different effects and treatments required in saline or fresh, and IIRC, depth can also have a significant effect of the metal.

There are refined and well supported treatment regimes, but I'm sure of anyone could come up with a 'Dorian Grey' treatment, they'd be popular.

Molasses are often used...

Good suggestions so far. Obviously the NMUSNA had a lot of data relating to freshwater recoveries, the Fleet air Arm Museum in the UK has a couple of aircraft recoveries too. The Halifaxes in the RAF Museum and the RCAF Memorial Museum, Trenton would be a good case study in contrasts as to post-recovery conservation vs restoration.

Keep us posted as to how you get on!

John Dupre · **Posted:** Thu Apr 09, 2009 6:56 am

The FAA website will have Advisory Circulars (AC) and there is a very good one on corrosion control for aircraft. There may even be one on evaluation of submerged aircraft dating from midwest floods of several airports.

As important as the type of water is the type of metal and its treatment prior to submersion. Navy aluminum aircraft were anodized and primed inside and out and withstand water immersion better than Army aircraft that were not. Assembly practices are also important. The Navy often required some type of barrier between joints with dissimilar metals.

The subject ought to lead to an interesting and informative project. Good luck.

Hal B · **Posted:** Thu Apr 09, 2009 9:28 am

One thing you don't want to do is pull it out of the water, spray it with oil and then park it on a trailer in a hanger for a couple of years

Typical Navy snafu.

That I know from working on one that was treated that way a few years ago...

John Dupre · **Posted:** Fri Apr 10, 2009 8:45 pm

I have heard of several aircraft recovered from shallow sea water that literally disintegrated before the vessel could get back to port. I know of another recently (last 10 years) ditched Navy warbird that on recovery was basically dumped in a swimming pool and boiled like an alka seltzer as the magnesium parts were consumed. The classic case was the F6F recovered off CA back in the 1970s. It was basically hosed off and put on display. It gradually deterioated over the years until the engine mount began to collapse. It ended up being totally rebuilt to static. I have read that the only real way to inhibit corrosion in a salt water immersed aircraft is to completely dissasemble every part and skin and treat all parts before reassembly. Salt caught in the joints and laps will continue to corrode the metal even after being washed down.

Seafury1 · **Posted:** Fri Apr 10, 2009 9:47 pm

If you are talking about salt water specifically, there is a chemical reaction that takes place between most metals and the salt. Mr. Dupre, I do believe, may have been speaking of a corsair that crashed in Florida in the mid 90's. I saw the airplane after it was in the hangar and every magnesium part was dust. I think the airplane was in the water for around 48 hours (I may be wrong) Also, salt will attack any metal be it on an airplane or your car and shorten the life span unless the metal is well treated, Anodize, Alodine, Zinc etc.

If you are speaking of fresh water, the effects are the same but at a much slower rate. The "Dottie Mae" sat under water for 60 years almost to the day. A lot of the mag was gone, IE; the nose case on the engine was deteriorated so much that the prop just fell off who knows when. The Dottie's skins are in incredible shape and may mostly be savable. The only thing that I can think is that the prep of the skin is key to combating corrosion in a liquid environment.

Being a Chemical Engineering major, I think the chemical reaction between water and metal would be an appropriate project. Who knows, maybe Mr. Cook can get you in touch with Allied Fighters and the "Dottie Mae" would be available to study. The guys that have it are great people and MAY be open to the thought. I would be interested to see what you come up with in your research.

Good luck!

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Aircraft Metal Degradation

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