Material of some medals

[matteti]

To our dear experts on the forum,
I was looking at the material (metal) used for the medals and found some contradictions between McDaniel book and Mondvor.narod.ru website. I know it's not of the highest importance, but I was curious to know more about this.

For Veteran of Labor and of Armed Forces:
- McDaniel says they are made of "an aluminium alloy"
- Mondvor says they are made of "silver-plated tombac"

For Strenghtening Military Cooperation:
- McDaniel says they are made of "an aluminium alloy"
- Mondvor says they are made of "golden color tombac"


Who is right and who is wrong?

Because after small research on the net, I found the definition of tombac:

An alloy of copper and zinc, resembling brass, and containing
about 84 per cent of copper; -- called also German, or
Dutch, brass. It is very malleable and ductile, and when
beaten into thin leaves is sometimes called Dutch metal.
The addition of arsenic makes white tombac

Nothing indicates any aluminium in the fabrication of tombac. And according to the definition of tombac, it seems possible to make it "white" or more silver by adding arsenic to the copper and zinc.

To make it more complicate, it seems that both BRASS and TOMBAC are made of copper and zinc... so, are they the same? or if not, I guess the proportion of each metal in the alloy is different.

If you know anything that can be useful to my learning, please just post it here. Thanks in advance.

[matteti]

On Mondvor, Moscow 800th anniversary would be made of copper and on McDaniel of Bronze.

Kiev 1500th anniversary of Brass ("latun") while McDaniel says it's Tombac.

I am currently doing some kind of cataloguing and award description for my own learning and would really like to clarify this issue.

Thanks.

[Taz]

Matteti,

These are the Metals used to my best knowledge.

The Veteran of Labor: is made of "silver-plated Tombac".
The Veteran of the Armed Forces: is made of "patiniert Tombac".
The For Strenghtening Military Cooperation: is made of "gilted Tombac".
The Moscow 800th anniversary: is made of "Copper plated Bronze".
The Kiev 1500th anniversary : is made of "gilted Tombac".

Copper on its own is very rarely used unalloyed in Medals, other than as a coating because it has relatively poor wear properties, its too soft.

Tombac is a brass alloy one mix in proportion would be 88% copper with 12% zinc. It generaly has a lower zinc content than Brass.

Brass is an an alloy of copper and zinc, although the term is loosely used to include all copper alloys. Generally the alloys used vary in composition from 3% zinc to 30% zinc, and vary in colour from the red of copper to a bright yellow. Brass with a small quantity of nickel is known as Nickel Brass.

Bronze is an alloy of copper and tin, usually 80% to 95% copper. Most modern 'copper' coins are actually bronze, as pure copper is too soft and rapidly shows extensive wear. While bronze is usually copper coloured, a high tin content will give a silver colour.

Cupro-Nickel Is self-evidently an alloy of copper and nickel, it is one of the most common alloys used in Medals. It is also called copper-nickel in the US by some. A related alloy called Alpaca also contains zinc.
It is silvery in appearance and hard wearing, and yet easy to fabricate.

Apart from the Moscow 800th anniversary being made of Copper I would say Mondvor wins that one easy.

Hope that helps.

Eddie.

[otlichnik]

Excellent questions Matteti and excellent details Eddie.

Interestingly (for me at least) this question is related to my other hobby, collecting ancient and medieval arms - many of which are made of copper alloys.

The problems of defining copper alloys is very difficult which is why archeologists use just that term "copper alloy" or give the exact metal breakdown. The problem is that the other terms are not exact.

You can see the huge variances in content in some of Eddie's examples. Latun, which is a very old original term for brass, and brass and tombac/tombec are, or at least can be all the same mixture.

In the end whatever the manufacturer calls it is usually the best term to use. Although I agree with Eddie that there is no way that the 800 Moscow medal is pure copper - you can scratch pure copper with your thumbnail, but not the medal.

Shawn

[matteti]

Thanks Eddie for these details.

As I see, these alloys can be made of the same metals, but in different proportions. So, it makes it difficult to precisely name an alloy.

I am starting to realize that, how interesting it can be to know the name of the metal (or alloy) a medal is made of, this doesn't help a lot in evaluating a medal for authenticity purpose among other. In that case, a precise weight and dimensions (+thickness) measurements would be more reliable and easier to obtain.

[Taz]

Matteti here are a few more Metals/Alloys for you.
-------------------------------------------

Aluminium or Aluminum as you guys in the USA call it.
Element (Al), Atomic No. 13, density 2.70 kg/litre, M.Pt 660°C

A very 'white' corrosion resistant metal.The pure metal is very soft, and so does not wear well. However, it is an important alloying addition.
BTW There is an apocryphal story that the absence of the second letter i in the American spelling was the consequence of a signwriter misspelling the word when the first producer of aluminium started up in the US! After all, the Americans don't use the words sodum, potassum, chromum or titanum, do they? However, I gather that this tale is an urban legend! :)

Aluminium Bronze Alloy
Copper-aluminium alloys, sometimes containing a small amount of manganese or nickel. They are yellow in colour and hard wearing. There is also a variety called Nordic Gold it has a composition of 89% Cu, 5% Al, 5% Zn and 1% Sn.

Antimony Element (Sb), Atomic No. 51, density 6.62 kg/litre, M.Pt 631°C.
Known since ancient times.
A silvery metal which is very brittle, and is easily crushed and powdered, and is thus an unlikely candidate for use in Medals. It is easily cast (melting at 631°C), and gives a clear impression of the mould. Its main use is as an alloying addition used to harden lead. It is used alloyed with tin, copper or lead to produce white metal used in the manufacture of medallions.

Barton's Metal Composite.
Barton's Metal is copper overlaid with a thick layer of gold.

Bath Metal Alloy
A type of cheap bronze.

Bell Metal Alloy
As it's name says, used mainly for bells. It is a type of bronze.

Billon Alloy
An alloy of copper and silver, with more than half copper.

Originally Posted by otlichnik

The problems of defining copper alloys is very difficult which is why archeologists use just that term "copper alloy" or give the exact metal breakdown. The problem is that the other terms are not exact. Shawn

Shawn,
Absolutly correct.
Although Brass is a term generally used for "all" copper Alloys.
Orichalchum was also an old name for a Brass Alloy back in the Roman days.

BTW just a bit of extra info. In Old English the Latin word aes was rendered as brass, thus the use of the word brass to mean money is still found today, especially in Northern England.

Many brass coins and Medals have been produced in modern times, although more complex copper alloys are normally used.
Various forms of brass have been used to make fake gold coins and Medals to deceive gullible collectors (the density is totally wrong), also I think a brass with 15% zinc is sometimes known as Goldine in the USA.

Eddie.