How does the Mint make "Reverse Proofs"???

dizzyfoxx

I just checked out a 2007 $50 Platinum Eagle 'Reverse Proof' and oh boy is that an incredibly attractive coin!
Can I get the ReverseProof 101 lecture on how they are made? I think they're fascinating.

relicsncoins

Just a guess; The planchets are prepared in the same fashion. (highly polished). The devices on the die are highly polished and the fields are roughed up for lack of a better term.

cinman14

Die prep in reverse....

Goldbully

Method of Manufacture
Reverse Proof coins are struck multiple times with specially polished dies and planchets (coin blanks) to produce an effect where the devices (details in the design) of the coin are mirrors and the fields (flat areas) are frosty. At certain angles, the mirrored devices appear jet black, and the fields a thick, frosty cameo.

The 2006 Reverse Proof Silver Eagles were struck at the Philadelphia Mint and bear the 'P' mintmark. The Reverse Proof Gold Eagle and Reverse Proof Platinum Eagle issues were struck at the West Point Mint and bear the 'W' mintmark.

Reverse Proof.com

YaHa

Silly ?. They pull the handle and put the lever in "R" mode.

dizzyfoxx

Thanks for all the input folks (even the silly ones).

jmski52

RWB

The night before reverse proofs are to be struck, the entire coining staff has a sleepover at the mint. They put their pajamas on backwards, and practice operating the presses backward.

In the morning the Plant Manager walks in backward, thanks everyone for what they haven’t done, tells them to stop what they haven’t started and cuts their salary. He also tells them what a lousy job they haven’t done and leaves by the entrance.

Then, a miracle happens. (Same as in Microsoft operating system development…)

Actually, they just polish the figure instead of the field, then laser etch the field to make it look sandblasted.

sinin1

sandblast they dies before being cut?

RWB

No. There are several ways to do this, but the easiest to explain is:

1) make a working die;
2) coat the die with a thin protective material (like a photo resist or frisket);
3) cut away the coating on the figure, stars and other relief;
4) polish the exposed areas;
5) remove the balance of the coating and add coating to the polished areas;
6) sandblast or laser etch the fields so they have the desired texture;
7) remove all coating traces, clean and inspect die;
8) chrome plate die;
9) put in press, enjoy.

Note: this can also be done entirely under computer control which obviates the need for protective coatings and helps reduce human error.

dcarr

<< <i>No. There are several ways to do this, but the easiest to explain is:

1) make a working die;
2) coat the die with a thin protective material (like a photo resist or frisket);
3) cut away the coating on the figure, stars and other relief;
4) polish the exposed areas;
5) remove the balance of the coating and add coating to the polished areas;
6) sandblast or laser etch the fields so they have the desired texture;
7) remove all coating traces, clean and inspect die;
8) chrome plate die;
9) put in press, enjoy.

Note: this can also be done entirely under computer control which obviates the need for protective coatings and helps reduce human error. >>



I doubt that they chrome-plate the die after polising/frosting. That would partially-obliterate both. I believe the steps (in order) are:

1) Make working die from working hub.
2) Heat-treat (harden) die.
3) Chrome-plate it.
4) Polish die, concentrating on the devices (if polishing "slips" into fields, no big deal).
5) Use clear tape to mask-off the devices.
6) Bead-blast die.
7) Remove tape.

A more advanced technique (as you mentioned) is to replace steps 5 through 7 with computer-controlled (targeted) laser etching.

RWB

As suggested, there are multiple ways to create mirrored coins with either "normal" or "reverse" mirroring and many different textures. As for when the chrome plating is done, I've been shown dies with plating done at different steps of the process, but one would need input from the technicians who actually do the work to get anything definitive.