Bathing resin castings in precious metals -- what's it called and how do you find out about it?

January 21, 2009

I am new to silversmithing and metal terminology, however as a sculptor with resin casting experience, I recently came across a silver-plating process that peeks my interest, used on some Italian-made sculptures I found offered on eBay . It involves creating a resin-cast object which is then bathed in baths of (pure?) silver, then copper and then sterling silver (and then possibly gold). First, what is the technical name for this process? Second, what specific type of polymer resin is used to withstand the high heat? Third, are there any chemical or non-chemical treatments involved? And, fourth (an idea), couldn't you cold-cast the resin mixed with copper powder to help bond the silver to the object (perhaps even saving the copper-dipping step)?

Here is an excerpt of the description of the process found on eBay:
"A liquid polymer resin is poured into the negative mold and takes as much as 10 days to fully cure. Some pieces have several different molds for different sections or parts. When the positive strike is completely hardened, it is removed from the negative mold and attached to other parts of the piece, if any...
"Applying silver is a difficult and labor intensive process. Unlike "silver-plated" items which are only dipped for a few seconds in silver, allowing for the silver color to eventually wear away, the process used on this item calls for several days of bathing and coating in silver. The bathing creates a high content of silver on the surface of the strike that never wears away and adds value and luster to the piece. Next, the resin strike is bathed in copper making the strike an attractor for the silver. The strike is then bathed in pool of .925 sterling silver for several hours, or even several days. The strike is removed from the molten silver and after it completely cures, it is polished by hand and coated with a varnish to prevent tarnishing. The content of silver in most pieces ranges from a few grams to a few ounces depending on the size of the piece. The pieces that have a gold coloration are made with actual 24 karat gold using a special heat burnishing gun that melts the gold over the silver. After their silver bath, pieces that are completely gold colored are actually bathed in 24 karat gold. Most pieces take a few weeks to complete. Some take a few months. Each piece is stamped .925 silver, and most pieces have a factory or studio identifying mark. Some are also designed by the original artist."

Eric Reagan
sculptor - Brattleboro, VT, USA