The Tinning Process
The goal of retinning a copper pan is to provide a new cooking surface by recoating it with thick layer of fresh tin. The result is a surface that will provide years of safe service.
First, the old tin is removed from the cookware and the raw copper is prepared to accept new tin. The surfaces are then covered with an acid flux which helps the tin adhere to the copper when heated.
The outer surfaces of the pot are protected with whiting to prevent the hot tin from accidentally sticking to the outside of the pot.
The pot is heated to approximately 450 degrees Fahrenheit which is the melting point of tin. Pure molten tin is then ladled into the pot and swirled around to coat the desired surfaces. The excess tin is wiped up with a flux coated cotton cloth and the pot is allowed to cool naturally.
The traditional "hand wiped" method of retinning applies a much thicker layer of tin than "electroplating" methods. You'll see some wipe marks in the finished product, but it will last much, much longer than electroplating.