Is this it?
I think that's probably the source of the allegation. It's a discussion thread about 2-2-V-1 on a forum that is ostensibly about aviation mysteries but spends most its time bad-mouthing TIGHAR in general and me in particular. Many of the participants are exiles from the TIGHAR forum and the level of vitriol (and misconception, distortion, and crazy speculation) is something to behold. I can guarantee that this posting will be copied and posted to that forum with scathing commentary.
A 1938 Naval Aircraft Factory report is referenced in a long, eyes-glaze-over tirade about 2-2-V-1 dating from a year ago and featuring what appear to be screen captures from various documents posted but there are no links to the actual documents. Without being able to see the original documents there is no way verify their accuracy and context. Three of the tables that are reproduced purport to show the percentage of various elements in the 24ST alloy in 1935, 1936, and 1938.
To summarize:
1935 - Copper 4.2%, Manganese .5%, Magnesium 1.5%, Zinc 0%. Nickel 0%, Chromium 0%
1936 - Copper 4.2%, Manganese .5%, Magnesium 1.5%, Zinc 0%. Nickel 0%, Chromium 0%
1938 - Copper 4.4%, Manganese .5%, Magnesium 1.5%, Zinc 0%. Nickel 0%, Chromium 0%
The percentage of various elements in the 24ST alloy in the samples tested for TIGHAR by Lehigh Testing Laboratories were:
1935 Electra sample 1 - Copper 4.29%, Manganese .43%, Magnesium 1.49%, Zinc .008%. Nickel <.0006%, Chromium .001%
1935 Electra sample 2 - Copper 4.06%, Manganese .48%, Magnesium 1.46%, Zinc .007%. Nickel <.0007%, Chromium .001%
1936 Electra - Copper 3.55%, Manganese .45%, Magnesium 1.46%, Zinc .006%. Nickel .0008%, Chromium .001%
1936-1941 Electra Jr. - Copper 4.48%, Manganese .59%, Magnesium 1.49%, Zinc .007%. Nickel <.0006%, Chromium .003%
If the numbers in the first group above represent the standard formula for the designated year, we can see that (not surprisingly) there was some variation in the actual alloy produced. Copper, in particular, seems to have wandered a bit and Zinc, Nickel, and Chromium were present in small amounts. They appear to be impurities rather than part of the formula.
WWII B-24 1943(?) - Copper 4.14%, Manganese .51%, Magnesium 1.42%, Zinc .021%. Nickel .003%, Chromium .024%
WWII B-17 1943 (?) - Copper 4.3%, Manganese .45%, Magnesium 1.31%, Zinc .024%. Nickel .004%, Chromium .018%
The WWII samples show more variation in the percentages of the basic elements of the alloy (Copper, Manganese, and Magnesium) and greater amounts of Zinc, Nickel, and Chromium.
How about 2-2-V-1? - Copper 4.49%, Manganese .62%, Magnesium 1.48%, Zinc .013%. Nickel .002%, Chromium .015%
More Zinc, Manganese and Magnesium than the 1935/36 aircraft but not as much as the WWII aircraft.
So what do we know?
• Assuming that the tables reproduced on the Aviation Mysteries forum are correct, the actual aluminum in Lockheed Electras varied somewhat from the standard formula and contained small amounts of impurities - Zinc, Nickel, and Chromium.
• The aluminum in the two WWII aircraft had virtually the same amounts of Copper, Manganese and Magnesium as the pre-war aircraft but greater amounts of Zinc, Nickel, and Chromium. What we don't know is whether this is due to a change in the formula or poorer quality control due to the huge volume of wartime production.
• 2-2-V-1 falls somewhere between the two groups,
So the allegation on the TIGHAR Facebook page:
"There is a USN chemical analysis report of 24ST dated 1938 freely available online that shows the same chemical analysis of your 1935 sample tests - The artefact is then clearly shown to be post 1938 production and obviously then of WW2 origin" is not supported by the available evidence.
We'll never be able prove that 2-2-V-1 is the Miami Patch but we may be able to conclusively disqualify it. We're not there yet.