Bizarre Mint Process

cosmicdebris

<<Certified PF62 by NGC, this is from the coronation proof set. Well struck, has some brownish toning probably left over from the bizarre mint process - coins were wiped by the mint workers that particular year. Please check my other auctions for high grade sixpences.>>



LINKY-POO

farthing

Well, that one didn't last long.





Better up your prices Tom!

AuldFartte

<< <i>Well, that one didn't last long. >>



Under an hour. Not too shabby

wybrit

I'm not sure where that brown crud came from, but the whole set except the crown, half sovereign and sovereign have it.

The set was originally purchased from Stacks. While I like matched sets, I want to replace each and every brown piece with a better one as time goes by.

agraded

Tom, I wish I'd known you had that coin up. The Sixpence and Shilling seem to be harder to find than the Halfcrowns...that was a very good buy. The only reference to wiping of Matte Proof coins I've seen was regarding the gold Matte Proofs that mint workers wiped upon their leather aprons in an unsuccessful attempt to make them take on a shine. No wonder the Royal Mint never produced another complete run of Matte Proof coins!

Bob

wybrit

I post most coins on my website before sending them off to ebay. That said, there are a couple, like the 1902 halfcrown and the 1927 proof sixpence that never made it to the web (reason being I decided not to slab them) and are now listed on the bay.

MacCrimmon

After seeing some of these silver matte proofs over the last several days the thought comes to mind that maybe this "streaking" may actually be the result of 'wiping' the dies, not the coins.

Were the mint workers using an oil or some other new substance which was overly viscious and tended to bond to the metal. Initially, nothing was noticed but over time the 'wiping pattern' appeared owing to the natural oxidation process of silver, and the "oil" residue left behind on the dies (ever seen two almost identical streaky patterns on the same denom?).

I've also heard about this apron wiping deal with gold, but how does copper generally appear (at least those which haven't been fussed with)? ....... obviously, I don't collect E7 MPs, so I've scarcely even looked at even the auction specimens.

syraq

Not a sixpence, but a DH picture's worth a 1000 words.





Nice coins wybrit.One halfpenny in particular.

agraded

After seeing some of these silver matte proofs over the last several days the thought comes to mind that maybe this "streaking" may actually be the result of 'wiping' the dies, not the coins.

Mac, that's a good observation as most of the streaked toning seems to be on the low points of the coin (the image is detail on a 1902 MP Florin).

MP1902Florin

ever seen two almost identical streaky patterns on the same denom?

From what I've seen the dark toning (charcoal or brown) usually follows the slightly swirling pattern of raised hairlines (for lack of a better term) that are present on GB Matte Proof coins. And this might come from deposits left in the dies if they were wiped. Or maybe I'm overthinking this whole #$%$ thing...now that is a possibility.

Cheers