How is a matte proof finish applied to a coin?

MrEureka

Is the die sandblasted?

Is the planchet sandblasted?

Is the coin sandblasted after it is struck?

Does the process leave any contaminants on the surface of a coin?

What else do you know about the process?

moneyhungry

Good Question !!! I would like to know that too !!!

MrSpud

From what I hear, either the dies were sandblasted or are given the rough texture in other ways (I've heard that different methods including pickling in acid, using lasers etc...). I also believe I heard that all proof dies have given similar textures (only sometimes finer and sometimes coarser) then the fields are polished smooth so that just the devices are textured.

richbeat

It might depend on the denomination of the coin. If you're referring to the matte proofs of the early 1900's, from what I've read, much of it is a mystery. In the case of matte proof cents, the speculation is that the dies were sandblasted and the planchets were acid treated.

A couple of exerpts from David Lange's "Complete Guide to Lincoln Cents:"

"The combined application of sandblasting and acid baths is believed to have been behind the matte proofs coined 1908-1916, as the new designs introduced beginning in 1907, with their sculpted surfaces and irregular fields, did not lend themselves to the traditional method of proofing."

"If sandblasting was used in the manufacture of proof Lincolns, it was probably in the die finishing process and not with the struck coins themselves."

"There is also no real evidence that acid was used on the struck coins, though it was undoubtedly a step in the normal cleansing of the unstruck planchets."

"In short, we simply don't know exactly how the proof cents of 1909-1916 were made. Some subtle distinctions appear within particular dates and from one date to the next."

ldhair

No one knows for sure.

Planchets probably had an acid bath and tumbled in saw dust and metal beads.
Dies were probably blasted but not the struck coin.

It's all guess work.

michael

on matte proof gold

the finish was applied after the coin was struck

and for the roman finish matte proofs gold of 1909 and some 1910 gold coins it was similar but it is too complicated for me to write on here and no one would read or care for it anyways

MrEureka

Michael - What's your souce on this info? And please do tell us about the Roman finish. I promise I'll read it!

michael

and no contaminants were left on the matte proof gold coins

but............

it might look so today

that you think contaminants were left on the matte proof gold coins

but again not so

as what you are seeing for most all matte proof gold coins in slabbed plastic holders today!!!!

are actually dipped to death and stripped matte proof gold done after the fact to increase the grade and eye appeal to investment buyers

this is true for the brilliant proof gold coins pre 1908 to find a true deep orange gold slight hazy yet still deeply mirrored and cameoed gold coin is a rare bird and in my opinion worth a permium

you see many bright gold monster cameo gold proof coins pre 1908 in slabbed holders and this is not a bad thing but it is not as good an an original thick skinned proof orange gold coin