DuPont DETACLAD "Explosion Bonded" clad coinage ingot sample circa 1964
dcarr
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I saw this while looking at random things on eBay. It was $350 "Buy it Now". I clicked as fast as I could. According to the available information, they were produced circa 1964 as a sample proof-of-concept for explosion bonded material for clad coinage to replace silver coinage. As such, it is related to some of the Franklin and Martha Washington test patterns.
A similar ingot with exactly the same imprint (but overall a little smaller in size) sold at Heritage auctions in 2006. That auction description indicated that it was likely unique. Apparently it is not unique (unless the exact size is considered). But it is still very rare, I believe. At the time that other ingot sold, the exact composition was not known (the auction writer made a "guess").
But I recently had an XRF test done on mine and here are the results:
Top layer: yellow brass.
Middle layer: stainless steel.
Bottom layer: pure copper.
Mine measures 66mm x 38mm x 17.5mm. The Heritage specimen measured 54mm x 30mm x 12mm.
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If the images don't show up, here are direct links to them:
top: designscomputed.com/coin_pics/detaclad_top.jpg
bottom: designscomputed.com/coin_pics/detaclad_bot.jpg
imprint: designscomputed.com/coin_pics/detaclad_obv.jpg
auction: designscomputed.com/coin_pics/detaclad_auction.jpg
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Comments
I have one of these, as well. Very neat piece of exonumia! A handful of others have popped up since the Heritage auction, but they are rare.
What are the overall dimensions of yours ?
Do you think yours is the same composition as mine ?
Does the middle layer of yours attract to a magnet at all ?
I suspect the composition is the same as yours, and also that the size is similar. I will measure and photograph mine in the morning.
I've seen a photo of at least one example that looked like it had a different composition, so I definitely would not assume that all of them are the same.
This is the one I remembered seeing that looks quite different:
https://www.worthpoint.com/worthopedia/dupont-detaclad-explosion-bonded-1893900363
I was able to find photos and measurements of mine from the original eBay listing. As you can see, it differs from yours in that the inner layer is relatively thick, with two relatively thin outer layers. There is also a distinctly wavy boundary between the layers on mine, whereas your layers look flatter (although they do have a minute waviness to them). The measurements were given as 50mm x 37mm x 11mm, but I will double check that in the morning, and see if it is at all magnetic.
Edit: Another difference is is that after the word "DETACLAD", mine does not have the ® symbol, like the one posted above, or the "TM" symbol, as yours has.
https://www.worthpoint.com/worthopedia/dupont-detaclad-explosion-bonded-2004321184
Amazing!
Opens the door for a collection of materials and interfaces
CuNi anyone?
So four that I know of at this point, and no two are exactly alike. Now that I look closer, the Heritage ingot also has the ® symbol, while mine has a "TM" (TradeMark) symbol.
The boundaries on mine appear quite straight and planar. But I just learned something that I didn't know. There is a very fine (small-scale) tooth pattern at both boundaries. Like a miniature version of edge reeding on a coin. I assume this is to aid in the bonding of the metals.
Here are pictures of the edge:
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If the pictures do not show up, here are direct links to them:
edge: designscomputed.com/coin_pics/detaclad_edge.jpg
bond layer: designscomputed.com/coin_pics/detaclad_bond.jpg
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Very interesting thread and great items.
In the evolution of trademarks, perhaps the age of the items would be:
Exactly. Mine has the same thing, but at a larger scale, and the other example I posted has the same thing at an even larger scale.
I’ll ask the obvious question: why is it called explosion bonded? I’ve watched enough Forged In Fire to understand the basics of some metal bonding but I haven’t come across this term and explanation.
I thought that stainless steel was not magnetic.
Very interesting thread and samples...My curiosity is peaked, so I will have to research this. Initial thoughts are that it would be more expensive than the plating process (which I am professionally familiar with). Cheers, RickO
Have you all compared these little ingots to the various compositions listed in Roger Burdette’s fine book on the patterns of this era?
Like some other readers here, I personally remember the events surrounding the removal of silver from circulation.
However, I ain't never seen one of these before. Thanks for sharing and to others who shared their knowledge.
Goes to show that after 50+ years, there still plenty left to learn, and that's exciting.
"In 1962, DuPont applied for a patent on the explosion welding process, which was granted on June 23, 1964 under US Patent 3,137,937[2] and resulted in the use of the Detaclad trademark to describe the process."
"Explosion welding can join a wide array of compatible and non-compatible metals; with more than 260 metal combinations possible."
Are there that many bricks?
We have some explosion clad equipment at work. It's a very cool process.
IG: DeCourcyCoinsEbay: neilrobertson
"Numismatic categorizations, if left unconstrained, will increase spontaneously over time." -me
Here's one of the Ben Franklin patterns with dies made by August Conrad Frank of Philadelphia. This one is NGC MS64. Interestingly, I've never seen a single one certified by PCGS.
Here's a page covering a few of these, including the mule of the Ohi-Yesa store card die and Treasure Island So-Called dollara die.
https://www.coinauctionshelp.com/Pattern_Guides/dupontpatternsquarter.html#.YMItSDZKjyg
Here's the 1964 granted US Patent by Holtzman Arnold Harold of EI Du Pont de Nemours and Co.
Some forms of stainless steel can be slightly magnetic.
Two or more sheets of metals are laid flat and pressed together hydraulically. Then dynamite is detonated to complete the bonding. Early clad quarters and dimes were composed in such manner but very soon they were able to roll these together which is an easier process.
Are any of the coins released for circulation bonded by dynamite?
The reference quoted did not state how many bricks.
I would guess with 260 metal combinations many of those combinations have been produced.
If I find other info I will post it.
It looks like there may have been 500 of the Franklin pieces produced.
"A special set of dies were made to produce 500 pieces for presentation” featuring the Franklin portrait."
316 stainless steel (see below for composition) is an alloy steel that is less magnetic than the 304 grade which contains nickel and chromium.
316 Stainless Steel Nominal Composition in Percentage:
Ni 12.00 Cr 17.00 Mo 2.50 Fe Balance Si 1.00 Mn 2.00 C 0.080 P 0.045 S 0.030https://www.espimetals.com/index.php/technical-data/202-Stainless Steel 316 - Alloy Composition
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Roger Burdette notes in the book that the ingots are not of the same coinage composition that Dupont used to make the quarter-size tokens.
@dcarr
The measurements on my ingot are 49mm x 37 mm x 11 mm.
The middle layer is slightly magnetic - enough that a very light magnet will stick to it, but not a heavier one.
Based on the colors, my ingot also appears to be made up of copper, stainless steel and yellow brass. However, on my ingot, the top layer (with imprinted text) is copper and the bottom layer is yellow brass, so that is another difference between yours and mine.
Oye vey
How is this coin related
See Roger Burdette’s book.
This is part of the history of our clad coinage.
Very interesting piece! That is a cool piece.
Very interesting! Thanks for the explanation. I wouldn’t imagine it would be a practical method for something like our coinage - even at the 1960s era mintages let alone today’s mint output.
I use shell and tube heat exchangers that are suitable for sea water which have titanium bonded to carbon steel tube sheets. Somehow I would think that explosion bonding would be way too expensive for coins.
Hi, I found this at my parents house. My grandpa worked for DuPont. Is this the same as what you are all mentioning ?
https://ibb.co/4MmrVm5
https://ibb.co/bNNS7Nm
https://ibb.co/r3VFWpH
https://ibb.co/9vkQd2V
It is indeed.
Neat - that is the first example I've seen embedded in lucite.
It looks like it has exactly the same stamp as mine, but the overall size of your ingot is smaller, so the text appears larger in relation to the face dimensions of the ingot. Also, the outer layers are thinner in relation to the inner layer.
So far, it looks like no two of these are exactly alike.
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Pretty cool.
Hoard the keys.
Never knew about these ingots. Very cool.
I recently came across another one. Most notably, it doesn't say "DETACLAD" on it. This is the only one I've seen with "EXPLOSION CLAD" marking. It is also smaller at 49.5mm long by 25.0mm wide by 11.5mm thick. The outer layers are thinner than the inner layer. The layers appear to be copper, stainless steel, brass. This one has the same small-tooth bonding interface as my other one. This version without "DETACLAD" and without any trademark symbol may be the earliest type.
Cool !
Does the stainless attract to a magnet ?
It would be interesting to find some DuPont product development documents that show the progression.
I knew it would happen.
the one in lucite or whatever was sawed from a much larger/longer piece, a common practice for such items (various types of stock). makes me wonder if there are a lot more of these or if they have suffered the fate of many items containing metals known to be melted/smelted.
Since it was given out as an advertising promotional paperweight, I'm sure there are others out there. Very neat item.
Worry is the interest you pay on a debt you may not owe.
"Paper money eventually returns to its intrinsic value---zero."----Voltaire
"Everything you say should be true, but not everything true should be said."----Voltaire
Very cool find!
I agree this could be the earliest type.
I found 3 TradeMark registrations for DetaClad. The 1965 registration is for DuPont (https://www.dupont.com/), while the later two are for DMC Global (aka Dynamic Materials Corporation - https://www.dmcglobal.com/).
Here's one that was slabbed by our hosts:
Also, of note, I took a closer look at the text under Franklin which indicates this was struck by August Conrad Frank of Philadelphia!
I wonder if the obverse die was used for any other tokens or medals?
I have some interesting stuff that was dated to the late 1960's via an estate that I think may be related to the switchover from silver-clad to clad coinage, including what I believe to be pre-production Ike dollar blanks. Should take some good pics sometime and share them.
"It's like God, Family, Country, except Sticker, Plastic, Coin."
Really interesting thread of history here.
Paper money eventually returns to its intrinsic value. Zero. Voltaire. Ebay coinbowlllc
Agree 100%. This is a very fascinating topic.
This gets me wondering how are standard clad coins bonded?
By the way, there are lots of articles and images on explosion bonding online like this one:
Ref: https://www.totalmateria.com/page.aspx?ID=CheckArticle&site=kts&NM=489
I don't believe any have been produced this way since about 1968. Even a few '65's didn't use explosion bonded I believe. Steels have become much stronger since the '50's and sufficient pressure can be imparted by rollers.
Early clad coins, especially '65 and '66 quarters were notorious for coming apart. I used to joke that the explosion bonding process was guaranteed for only 30 years and and would fail violently at any point after that. Bags or rolls of quarters could even go up in a large cascade failure.
The explosives were just used to get the last little bit of pressure to complete the bonding.
Any metal can do this but once in a while if you rub a couple clad quarter together they will stick and will require a surprising amount of force to separate. The surfaces just interlock similarly to the bonding process.
This post, the history, and metallurgy is fascinating. I admit that the topic prompted me to do some more research into DuPont and the cladding procedures. I have some particular interest in that one of DuPont's major research facilities was very close to where I grew-up. Thanks for sharing.....