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<p>[QUOTE=&quot;Sulla80, post: 18819188, member: 99456&quot;]Process for making plated coins: There were multiple processes potentially used to make plated counterfeit and official coins throughout time. While there are several candidates for silver plating in ancient Rome, there is uncertainty about the process used for late Roman coins. Here are several candidates :</p><ul> <li>&quot;<b>diffusion bonding</b>&quot; or &quot;<b>Sheffield plating</b>&quot; : silver copper sheets heated together reported in use for Roman Republican fourrée denarii, wrap copper flan in a silver foil and heat. This is considered too labor intensive to have been used at scale in late roman empire</li> <li>&quot;<b>dipping in silver chloride</b>&quot; - Blanks were maintained hot, dipped in molten silver chlorides, and quenched in a bath</li> <li>&quot;<b>mercury silvering</b>&quot;, &quot;<b>amalgam plating</b>&quot;, or &quot;<b>fire gilding</b>&quot; - a good way to get mercury poisoning - dissolve silver in mercury, then spread on the flan like peanut butter, then evaporate the mercury with heat, this technique is mentioned as a possibility for late roman coins.</li> <li>&quot;<b>depletion silvering</b>&quot;, &quot;<b>pickling</b>&quot; or &quot;<b>blanching</b>&quot; - take a copper-silver alloy - use citric acid or vinegar to leach out the copper and enrich silver content of the outer surface, then strike to produce a silver surface plating which seems to be a leading hypothesis for later Roman coins.</li> </ul><p>Ancient technology was a surprisingly sophisticated and included ploughs, irrigation, wheels, textiles, aqueducts, writing, ships, complex construction, and most relevant for this discussion: metallurgy of gold, silver, copper, and bronze. Bolos of Mendez in the second century BC describes methods for producing false silver:</p><p><br /></p><p><i>&quot;About the making of “uncoined”: the quicksilver from arsenic, or sandarach, as you prefer, cook it as usual, deposit it on copper or coppered iron, and it will be whitened. Whitened magnesia does the same thing, and transmuted </i></p><p><i>arsenic, and cooked cadmia (ZnO?], and unfired sandarach and whitened pyrite, and psimuthion [lead acetate] cooked with sulfur.&quot;</i></p><p><i><br /></i></p><p><i><br /></i></p><p>For a collection of notes on ancient coins visit: <a href="http://www.sullacoins.com/" target="_blank" class="externalLink ProxyLink" data-proxy-href="http://www.sullacoins.com/" rel="nofollow">http://www.sullacoins.com/</a>[/QUOTE]</p><p><br /></p>

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