Is there anyway we can lay our hands on a pre WWII piece of Alcad and then do a spectro analysis comparison of a known sample and 2-2-V-1?
In 1996 ALCOA cut three large "coupons" out of the artifact (broke my heart) and ran analyses to determine the makeup of the metal. They found it to be identical to the pre-war, wartime, and post-war makeup of 24ST ALCLAD (since 1954 known as 2024 ALCLAD).
Can Alcoa suggest any processing changes we could look for on 2-2-V-1, such as flat plate rolling process marks, heat treatment, rockwell hardness, anodizing chemicals, coefficent of expansion specifications, chemical properties i.e. tin, lead, aluminium content, etc., tensile/shear strength or other physical properties we might be able to test in order to get a date range on 2-2-V-1?
I don't know. We'd have to start over with ALCOA. I doubt that any of our contacts from 18 years ago are still around.
Can we chemically compare 2-2-V-1 to a known original Lockheed 10E sheet metal fragment?
We already know that it's the right stuff in the sense that it's 24ST ALCLAD. A technique known as Neutron Activation Analysis could identify trace minerals in the alloy which, if compared to a known sample of metal from NR16020, could tell us that the two samples came from the same "batch" of aluminum. But even then we run into a couple of problems:
• How big was a "batch"of aluminum in 1936/37? Big enough for metal from the same batch to be sold to several manufacturers?
• According to ALCOA, the labeling on 2-2-V-1 indicates it is "reserve stock." The only known surviving example of metal from NR16020 are souvenir scraps from the Luke Field accident and, therefore, from the original construction, not the repair. Was the "reserve stock" used in the repair from the same batch of aluminum as the metal used in the original construction a year earlier?
• Neither of the individuals who own fragments of metal from NR16020 is TIGHAR-friendly.
Bottom line: Neutron Activation Analysis wouldn't reliably narrow the field.