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[JNev]

Really cool if that happens.  What's left of the characters is in poor condition, and by the late-find of an additional character (Michelle in Dayton) we can reasonably expect there could be more.

I have to admit that I came to wonder just what the hyper-spectral imaging might really tell us about 2-2-V-1 after all this time, but can see that this may be one example and I hope it pans out well.  There must be traces of those characters that we simply cannot see with the human eye under normal magnification, etc.

[Mark Pearce]

Thanks for posting that image.  Contrary to our earlier impression, it's clear that the font on the artifact is different from the font used on the AN-A-13 designation.  The font on the artifact is serifed and the shape of the space within the D entirely different.

In earlier discussions you made a compelling case that the AN-A-13 specification appeared circa 1942. If the AD on 2-2-V-1 is part of "ALCAD 24ST T3 AN-A-13" as we once thought, it would disqualify the artifact as dating from 1937.  That has been worrying me, even as the evidence snowballs that 2-2-V-1 is from the Miami Patch. Now we can see that our earlier impression was wrong.   Yes, AN-A-13 came along later and metal marked AN-A-13 ended up on repairs made to a C-47 and a Lockheed 10 but that is all irrelevant.  The fonts are different.  We still don't have a match for the font seen on 2-2-V-1 but at least we know it has nothing to do with AN-A-13.

Here is an example of Alclad marked with Italics, Serifs, and... AN-A-13.

[JNev]

Cool, another variant!  Shows that serifs were still around in the 'modern era' I guess.

Can you get some more examples?  The more the better.

[Ric Gillespie]

That's interesting.  The top piece has what appears to be two separate but different labels stamped on it.  The D in ALCLAD 24 S-T seems to be fairly close to the D we see on 2-2-V-1 and the AN-A-13 specification does not appear as part of that stamp.
The lower stamp is unlike what we see on the artifact and seems to be specifically an AN-A-13 stamp.

 This would seem to confirm that there was an ALCLAD 24 S-T stamp in a font resembling that seen on the artifact that existed separate from stamps containing the AN-A-13 designation.

[JNev]

That's interesting.  The top piece has what appears to be two separate but different labels stamped on it.  The D in ALCLAD 24 S-T seems to be fairly close to the D we see on 2-2-V-1 and the AN-A-13 specification does not appear as part of that stamp.
The lower stamp is unlike what we see on the artifact and seems to be specifically an AN-A-13 stamp.

 This would seem to confirm that there was an ALCLAD 24 S-T stamp in a font resembling that seen on the artifact that existed separate from stamps containing the AN-A-13 designation.

...and THAT makes me wonder if stock that was lying around got re-identified later after the spec emerged.

If I recall correctly, the spec simply identified a manufacturing feature that was already in existence - it merely validated a certain attribute.  Now if I can remember what that was... 

Real point here, I think - TONS of combinations and possibilities as to how sheet stock was marked are out there, from all eras.  The more examples we can see, the more likely we are to clear up what is on 2-2-V-1 - and perhaps clear up any doubt about 'era' as well.

[Mark Pearce]

That's interesting.  The top piece has what appears to be two separate but different labels stamped on it.  The D in ALCLAD 24 S-T seems to be fairly close to the D we see on 2-2-V-1 and the AN-A-13 specification does not appear as part of that stamp.
The lower stamp is unlike what we see on the artifact and seems to be specifically an AN-A-13 stamp.

 This would seem to confirm that there was an ALCLAD 24 S-T stamp in a font resembling that seen on the artifact that existed separate from stamps containing the AN-A-13 designation.

...and THAT makes me wonder if stock that was lying around got re-identified later after the spec emerged.

Real point here, I think - TONS of combinations and possibilities as to how sheet stock was marked are out there, from all eras.  The more examples we can see, the more likely we are to clear up what is on 2-2-V-1 - and perhaps clear up any doubt about 'era' as well.

Jeff, as sketched out below by Jeff Carter in April, there appears to be NO variation in Alclad markings in the pre-war era.  The font appears to have followed a single pattern. 

I now tend to see the italics found on 2-2-V-1 as more of a 'disqualifier' than anything else.  Alclad labels appear to have used italic fonts only during the war, and post-war eras.

http://aluminummarkings.wordpress.com/   

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http://tighar.org/smf/index.php/topic,1426.msg31293.html#msg31293

The question I wrestle with is that the forum has discovered numerous examples (over 20) of labelled 1930s aluminum from books, research reports, and factory photographs.
- All show labels of "ALC24ST" or "24SO" or "24ST"
- No examples show the word "ALCLAD" in any way.
- All show serif font (similar in many ways to a typewriter-style font)
- No examples show a san-serif font.

[Ric Gillespie]

I now tend to see the italics found on 2-2-V-1 as more of a 'disqualifier' than anything else.

Why does that not surprise me?  I tend to see the remnants of labeling on the artifact as one piece of an extremely complex jigsaw puzzle.  All of the other pieces we've found fit together and seem to be showing us a clear picture of the Miami Patch.  At present, we don't understand how the labeling fits but it seems like somehow it must.  More research is needed. You seem eager to jump to the conclusion that the labeling disqualifies the artifact without addressing the rest of the puzzle. 
I'm not much interested in what you tend to see.  Let me know when you've found proof of your assertions but I won't be posting any more of your opinions.

[Monty Fowler]

I blame myself. Should have left that dead groundhog in the roadside ditch, where it was unobtrusively residing.

LTM, who occasionally speaks in non-riddles,
Monty Fowler, TIGHAR No. 2189 ECSP

[JNev]

I blame myself. Should have left that dead groundhog in the roadside ditch, where it was unobtrusively residing.

LTM, who occasionally speaks in non-riddles,
Monty Fowler, TIGHAR No. 2189 ECSP

Can't blame you, Monty - who would pass up K.I.S.S.ing a dead groundhog?

LTM, who is known to have fetched road-waffled 'possum to the house for 'pizza'... 

[Chris Johnson]

Ref the fonts or markings on the Aluminium, rather than go around the houses shouldn't we be looking for documentary evidence as to the standards used? i.e a document that tells employees that this is the stamp that is to be used.  Then if you have s piece with divergent markings you may have a piece that has been labelled twice or am I just being simple.  Surley there was a set procedure for this kind of thing.

[Ric Gillespie]

Ref the fonts or markings on the Aluminium, rather than go around the houses shouldn't we be looking for documentary evidence as to the standards used?

Absolutely.  Trouble is, information that obscure does not seem to be on line and that means doing boots-on-the-ground research. 

[Jeff Carter]

Ref the fonts or markings on the Aluminium, rather than go around the houses shouldn't we be looking for documentary evidence as to the standards used? i.e a document that tells employees that this is the stamp that is to be used.  Then if you have s piece with divergent markings you may have a piece that has been labelled twice or am I just being simple.  Surley there was a set procedure for this kind of thing.

Well, it's a tricky problem.  The available texts are limited, and many needed references are not available on Google Books or Hathitrust.org due to copyright.  Alcoa documents would obviously be ideal. 

However, the general history of aluminum markings can be deduced from the available reference materials:

Phase 1: Proprietary Markings -- Prior to the massive increases in aircraft production in the early 1940s, the markings were defined by the aluminum manufacturer.  Numerous books and manuals state "AL" and "ALC" were the standard abbreviations for Alclad.

Photographs show Alclad aluminum was marked with the prefix "ALC", e.g., "ALC 24ST".

Phase 2: QQ Specification, 1941 -- In the early 1940s, Federal government QQ specifications are issued for major metal types.  Specifically in 1941, specification "QQ-A-362" is issued covering Alclad 24 Aluminum.  ( Ref: National Directory of Commodity Specifications: Classified and ..., Issue 178.   By United States. National Bureau of Standards, Paul A. Cooley, Ann Elizabeth Rapuzzi.  http://books.google.com/books?id=h6iOBWpe0ogC or hathitrust.org.)  Although the QQ-A-362 specification is not available, the above source states the specification included marking and labeling requirements of the Alclad aluminum ("packaging, packing, and marking for shipment").  [See Attachment 1 below.]

At this time, photographs start to show aluminum marked with more extensive labeling including the word "ALCLAD". 

War Department Technical Manual TM 1-424, "Aircraft Hardware and Materials", June 1942 describes the markings expected to be found on aluminum.
( http://babel.hathitrust.org/cgi/pt?id=uc1.b3241791;view=2up;seq=16 )  [See Attachment 2 below.]

Phase 3: AN-A-13 Specification, 1943 -- The AN-A-13 (Army Navy Aeronautical Specification) is issued in 1943 covering Alclad 24.  A second version AN-A-13-2 is released in 1944.  ( Ref: National Directory of Commodity Specifications listed above.)  [See Attachment 3 below.] 

Photographs of aluminum sheet begin to show "AN-A-13" markings. 

Phase 4: Post-WW2 -- Equally fascinating, but does not concern us here.

[JNev]

Looks like a good start, Jeff - that's fine research, you've surely dug out a good bit of rare material.  Informative, thanks!

[Ric Gillespie]

Phase 1: Proprietary Markings -- Prior to the massive increases in aircraft production in the early 1940s, the markings were defined by the aluminum manufacturer.  Numerous books and manuals state "AL" and "ALC" were the standard abbreviations for Alclad.

Photographs show Alclad aluminum was marked with the prefix "ALC", e.g., "ALC 24ST".

Dividing the history of aluminum markings into "phases" implies hard boundaries. That can be misleading.  There seems to have been a period before the federal government got into the act (circa 1941) when markings were the prerogative of the manufacturer.  During that time, ALCOA was the only manufacturer of 24 ST ALCLAD.  There is abundant evidence that, during this pre-war period, ALCOA routinely abbreviated ALCLAD to ALC in labeling 24 ST sheet.  We don't know whether they ever deviated from that protocol or when they shifted to using the word ALCLAD but, at some point, the word ALCLAD starts showing up.  That could be because it was mandated by QQ-A-362 circa 1941 but it could also be that the new government spec merely formalized what ALCOA was already doing.  Pinning down exactly when the word ALCLAD started appearing on aluminum sheet is really tough.  For example, you can find photos of aluminum labeled ALC being used to build a Boeing 314 (first flight June 1938) but who can say when that aluminum was rolled and labeled?

 

[Brad Beeching]

Since we are discussing an era when pretty nearly anyone with the means could build an airplane and fly it, do you think that maybe the air racers or homebuilders of the day may have kept records? Do you think it's worthwhile to try to find out if maybe they could have photos of other documentation of what and when they purchased the materials? Where do you even begin a search like that?