How much longer will aircraft wrecks be useable for restorations?

No limit except human

[QUOTE=tftoc;2038205]The recent recovery of the Do 17 has got me thinking about how much time the remaining wrecks around the world from the 1940s and earlier have left that they can still be considered a source useable components for an airworthy restoration project

Are we close to the point where galvanic corrosion on salt water wrecks has rendered all metal components unusable, even for patterns? If not then how much time is left on the clock? (And no, the data plate doesn’t count.)

There is a technical answer and a human answer.

Technical.
Bronze age artifacts remain and gold from ancient Greece remains. Very few metal aircraft will remain because their metallurgy will not support it. Duralumin is a mix of copper and aluminium, one eating away at the other, so intergranullar corrosion will accomplish in a century what we were originally injuncted to do ” beat the swords into ploughshears”. The mania for originality in parts is technically supportable while stocks of spares remain and metallurgy remains in a safe state, but a new generation of custodians needs to develop a practical philosophy towards regenerating the DNA of historical aircraft. My tuppeny’s worth is that where modern metallurgy exceeds the performance of decades old metallurgy the modern material must be used in preference to original metallurgy, simply for the sake of longevity, and thus safety. Technically, every aircraft must use silicon aluminium prior to 1930 to be ‘authentic’, but why, when it is unobtainable and will turn to powder very quickly. Technically, most British aircraft must use Duralumin through to WW2, but why, when Alclad will last 80 years longer. If I am to invest 100 man hours in a part, I would like to amortize its longevity across 200 years, not 50 years. There is really no limit to replicating parts on an aircraft, so no reason why an aircraft cannot last 1000 years. I understand that my own DNA is replicated every day, so I am not the same charming, good looking, slick dresser I was a day ago, but a copy. Still 100% “full of it” authentic but !

Human.
Aircraft are complex mechanisms beyond the powers of one individual to create, let alone recreate. Governments originally collectivised national resources and harnessed many individuals and enterprises to create a finished product. While, in the last 50 years, it was possible for an individual to amass the spare material consequent to this collectivist effort, it was possible for restoration/preservation to be a glorious extension of meccano or lego work. Need a new bakelite distribuor cap, take one off the shelf. An individual can do it. Need to make a new bakelite distributor cap ? Whoa ! The model of the eccentric individual in historic aviation preservation, as wonderful as they are, needs to be supplanted by the collectivist, working with like minded individuals to recreate a finished product, an amalgam of complex manufactures. Specifically, where you make one part, make 100 in the service of history, and network to distribute them. In turn, the network will supply you with what you may need. Unless this transition occurs all these wonderful mechanisms will fall silent as all the mass of anonymous parts under the skin become apparent. Hydraulic systems, high voltage ignition systems, pneumatic systems, braking systems, metallurgy etc. What really worries me are all the drop hammers, casting plants, heat treatment plants, steel manufacturers etc closing down. The ability of ‘short run’ , interesting historical engineering projects to be slipped in by sympathetic businesses between the manufacture of refrigerator trim and car parts. It’s like a closing door that desperately needs a realistic reappraisal of the human attitudes in historical aircraft restoration. Unite or perish, comrades !