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 Post subject: When did large-scale commercial casting begin?
PostPosted: Wed Nov 12, 2014 11:26 am 
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Hi Folks,

Hope I'm in the right forum for this one! Here's my broad question -- when did casting of jewelry, in general, become widespread in use?

Specifically, my question relates to a typical, simple gold wedding band. Today, I assume, and please correct me if I am wrong, the vast majority are cast. But when did this begin? Prior to the widespread use of casting, I assume a plain band would have been forged, correct? I am trying to explain to someone that an older wedding band from around 1900 is likely to have been forged, rather than cast, but I need to verify this before I put my foot in the wrong place.

TIA,

Neil


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 Post subject: Re: When did large-scale commercial casting begin?
PostPosted: Wed Nov 12, 2014 12:23 pm 
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Many wedding bands are die-struck.
Like Larter's, for instance.

Casting, gold, has been done since ancient times. These castings were gravity pours. The first written account of lost wax casting was 1100 AD in the works of Theophilus.
During the 1500s lost wax casting became much more sophisticated. Benvenuto Cellini's writings describe the advancements.

Use of centrifugal casting, for gold, as I understand it, began with dentists in the early 1900's, and became commercially common with jewelry in the 1940s.

Casting platinum was not commercially done before the 80's....1980's that is.


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 Post subject: Re: When did large-scale commercial casting begin?
PostPosted: Wed Nov 12, 2014 2:34 pm 
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Hi Barbra,

Thanks. Good info. So if I'm looking at a gold band from around 1900 (allegedly) it would most likely not have been cast. Would it be more likely that it was die-struck, or hand-forged? (Or is that an impossible call to make?)

Neil


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 Post subject: Re: When did large-scale commercial casting begin?
PostPosted: Wed Nov 12, 2014 2:47 pm 
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Any maker's marks?
If the ring was made by a company in the business of making wedding bands, it was probably die-struck. One only, most likely hand fabricated.


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 Post subject: Re: When did large-scale commercial casting begin?
PostPosted: Wed Jul 22, 2015 1:27 pm 
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This is probably a little late for this thread, but certainly in the U.K. jewellers made a point of hand forging wedding bands from the solid (it was a legal requirement to make a wedding band from 22ct, so it was quite easy)
To provide a definitive answer is not easy, but I would try flatting and polishing an area, then etching it to reveal the crystal structure. That ought to tell whether it was forged or die struck.


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 Post subject: Re: When did large-scale commercial casting begin?
PostPosted: Fri Jul 24, 2015 8:42 am 
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Hi Alan,

It's never too late for a good discussion! Thanks for your input. The ring is long gone, so I can't examine it (not that I have the skill to perform the test you suggest). But I was quite interested in the comment you made about the legal requirement for UK wedding bands to be made of 22kt. I'm pretty sure this is no longer the case -- do you happen to know the time period when this law was in effect?

Thanks,

Neil


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 Post subject: Re: When did large-scale commercial casting begin?
PostPosted: Sat Jul 25, 2015 5:20 am 
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Probably repealed during the First World War, when the U.K. was desperately short of money. Interesting to remember in this context that the coinage of the country at the time was 925 silver, then in 1917, in an effort to raise money, it was debased to 500 silver


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 Post subject: Re: When did large-scale commercial casting begin?
PostPosted: Sat Jul 25, 2015 6:46 pm 
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Sorry, forgot to add that in the U.K. hallmarks give the year an item was marked. This was not for the convenience of the antique trade, but so that, in the case of any fraud the Assay Master concerned could be traced and punished.
As regards checking the crystal structure of metal, it is fairly straightforward. Grind a flat with successively finer grades of carborundum paper, then etch the surface (a drop of acid test solution will do the trick), then examine the surface under the microscope. Fine grain = likely to be forged, coarse grain = likely to be cast.
Any good metallurgy book will explain in great detail, I picked up a good one for 1p, (1 1/2 cents). The deal was, pay the postage and the book is yours for a penny. I jumped at it and then noticed it is a common offer!


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 Post subject: Re: When did large-scale commercial casting begin?
PostPosted: Sun Jul 26, 2015 12:54 pm 
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I'd love to see some photos of this.
When I think of acid etching, I think of meteorites.

Makes perfect sense. The cast pieces should be crystalline.
But, die-struck and hand fabricated?


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 Post subject: Re: When did large-scale commercial casting begin?
PostPosted: Sun Jul 26, 2015 2:13 pm 
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All metals are crystalline, but in a cast (particularly lost wax cast) item, the crystals are quite large, because of the slow cooling. In a forged piece, the working of the metal refines the structure and the crystals are quite small. The book "Working in Precious Metals" by Ernest A. Smith has some excellent photographs illustrating the point.


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