How are the solder alloy metals and impurities controlled in the pot?
Silver and copper tend to not dross out of the solder pot. Depending on the metallization on the board silver (Immersion Silver) or copper (Bare Copper or OSP over Copper) may actually leach into the solder pot. Adding pure tin to the pot will control the alloy. Impurities such as copper, palladium and silver will need to be monitered because they raise the melting point of the alloy. For instance the melting point of a lead free alloy will increase 25°C for every 1% of copper in the solder alloy.
