Dr. Sim\'s New Book......silvering with foil?

[Doc]

I was reading Sim's new book Roman Imperial Armour and it appears that gilding was performed by mixing mercury with gold then the mercury is evaporated and the gold deposited. Futhermore, in this book, the technique of tinning is also discussed in that molten tin was used to coat objects by wiping not dipping.

However, when the discussion switched to silvering, it appears that the only way it was performed was by the application of a thin silver sheet over the object either iron or copper alloy. IMHO, I think that silver sheet or foil would have been used for iron objects where the deposition process as in tinning would not work because silver does not bond to iron in the way tin does.

However, in copper alloy objects, the deposition process would work well. Thus I think that in copper alloy objects silvering was done the same way as gilding. It is known that silver can dissolve in mercury just like gold and the mercury can be removed without disturbing the silver. As a matter of fact, I read that ores could have been mixed with mercury to extract gold and silver then evaporating the mercury, either of the two metals mentioned could be isolated.

I would be hard pressed to believe that only gold could be beaten into a sheet form and used to cover an object or alternatively use a mercury amalgam BUT silver was only used in sheet form.

Gold has a high melting point as does silver both of which are exceedingly higher that the boiling point of mercury.

The book seems to suggest that ANYTHING that was silvered had some sort of silver foil wrapped around it. Case in point the centurio helmet from former Yugoslavia. Another book that seems to support the same idea about silvering is B&C 2. In this book, as well, silver application is only regarded with respect to sheet or foil application.

Any thoughts, evidence, etc if ALL silvering was only with sheet or is there evidence to suggest an amalgam as used in the gold process.

[Robert Vermaat]

Any thoughts, evidence, etc if ALL silvering was only with sheet or is there evidence to suggest an amalgam as used in the gold process.

I think this is certainly correct where Late Roman helmets are concerned: every item (down to the last rivet) was first encased with silver/gilded silver foil before assembly.

[Doc]

Robert,

Thanks for the reply. As far as gilt silver is concerned in the Late Period I agree. I also think that both in the Later Roman as well as during the principate, gilding was done by adding mercury to gold......this amalgam applied etc....you know the process.

However, what I am trying to find out is IF silvering was only conducted with foil/sheet or as a parallel method made into an amalgam with mercury, applied, then heated to remove the mercury and deposit the silver.

I know this would not have worked on iron but on copper alloy objects, it seems plausible.

I was told by a silver plating specialist here in the US that has studied ancient techniques (so he says) that quadruple plating was performed in the ancient world. In other words, an iron helmet would have been dipped into copper and then the copper covered helmet subsequently dipped in silver several times for a strong thick silver finish. However, over thousands of years in the ground, the silver would wear and appear to be sheet or foil although it was not originally.

I am not sure how much I believe this because there are NO helmets that I know of from any Roman period that appear have been dipped in any molten metal since there is no evidence of the dipping process on the inner part.