FORVM`s Classical Numismatics Discussion Board

Numism => Reading For the Advanced Ancient Coin Collector => Topic started by: curtislclay on February 06, 2009, 03:04:52 am

Title: Ancient cast bronzes: could the molds be reused?
Post by: curtislclay on February 06, 2009, 03:04:52 am
The As of Geta Caesar shown below is a well known ancient cast, of the sort Cohen called "cast in Gaul".  I know ten other specimens of the same cast, all from the same dies and with exactly the same centering, so all clearly derived from one and the same struck original.

This new specimen, however, is the only one to show doubling of the details on both sides.  On the obverse, note especially GETA CCAES, with double C.  On the reverse, there are two exergue lines crossing one another with about a ten-degree shift in angle; Minerva has a doubled shield, doubled spear, and doubled helmeted head; instead of COS, we see CCOOSS, and so on.

What I don't understand is how this particular mold got doubled details on both sides.  That seems to imply that both impressions were made simultaneously and the model somehow shifted, for it would be too much of a coincidence if the obv. and rev. molds were impressed separately and the counterfeiter just happened to make faulty double impressions on BOTH SIDES of this particular mold!

Moreover, were these casts produced in such a way that each mold could be used only once, since after pouring in the molten metal and waiting for it to solidify, the mold had to be broken apart to retrieve the cast counterfeit?

I must admit that I had assumed that the molds were reused numerous times, all casts in Gaul of a particular type presumably deriving from one and the same counterfeiter's mold.  In that case, however, we ought to find other specimens with the same doubled details as on the new specimen; but these is no trace of doubled details on the other ten examples of this cast that I have found!

The thought has crossed my mind that the new specimen could be a flubbed modern counterfeit of a cast ancient one.  Apart from the doubled details, the metal of this specimen has a reddish hue, whereas other casts in Gaul are regularly of yellow brass.

However, nothing else about the coin is at all suspicious.  It has the same centering as other specimens of this cast, and despite the doubling has sharper and fuller details than any of the other ten specimens.  It is convincingly patinated and has what look like ancient deposits, especially in the letters of the legend behind the emperor's portrait on the obverse.

24 mm, 8.02 g, 7h.
Title: Re: Ancient cast bronzes: could the molds be reused?
Post by: Ardatirion on February 06, 2009, 11:20:34 am
This is based entirely on speculation, but is it possible that the molds were created from a hub? That would explain the numerous matches and the doubling.
Title: Re: Ancient cast bronzes: could the molds be reused?
Post by: napki on February 06, 2009, 03:59:55 pm
Dear curtisclay, ancient casted imitations almost always made with the clay moulds which must be destroyed to free finished objects. Sometimes hurried worker making hundereds or thousands of moulds make occasional double impression. See discussion of ancient Yaudheya cast coins may be useful as similar technology widely used. Note also discussion of doubling very similar:

http://www.coincoin.com/I069.htm (http://www.coincoin.com/I069.htm)
Title: Re: Ancient cast bronzes: could the molds be reused?
Post by: Robert_Brenchley on February 06, 2009, 06:09:47 pm
In the case of Postumus' cast bronzes, die matches can be found on coins of differing size and weight, indicating the use of an intermediate stage between the die and the final mould. Could something similar have been happening here?
Title: Re: Ancient cast bronzes: could the molds be reused?
Post by: napki on February 06, 2009, 07:16:36 pm
In the case of Postumus' cast bronzes, die matches can be found on coins of differing size and weight, indicating the use of an intermediate stage between the die and the final mould. Could something similar have been happening here?

Yes, original official die strike "mother coin" which then used to create mould impressions. One mold = one finished casted coin only - must be crushed to free casted coin. Size and weight vary depended on shrinkage of clay mould, depth of impression and volume of moltened metal that fill it.  See discussion this book (I just find it in coincidence with Google search) pp. 390-392;

http://books.google.com/books?id=tmETAAAAYAAJ (http://books.google.com/books?id=tmETAAAAYAAJ)

I must make note however that date of writing is 1905 and conclusion "officially recognized...for provincial use" theory not current. That stated, list of mould finds and description of how technology work still concise and useful for present topic I think.
Title: Re: Ancient cast bronzes: could the molds be reused?
Post by: PeterD on February 07, 2009, 08:00:51 am
Warren Esty has a good web-page about ancient molds: http://esty.ancients.info/numis/molds.html

Judging by the pictures, molds could be re-used. However I can't imagine them being used very many times. It seems that to re-use them, each set of 10 molds would have to have been re-assembled in exactly the same way and how many times they could have stood molten metal running through them is anyone's guess.
Title: Re: Ancient cast bronzes: could the molds be reused?
Post by: curtislclay on February 08, 2009, 10:07:15 pm
napki and PeterD,

Thanks for the interesting and informative links.

This is a matter I have to learn more about!