What is Dross?
Dross is an oxide that is formed of the tin and lead in the solder. Dross is generated by a combination of heat and agitation. The hotter the solder pot is, the faster the dross is generated. Also, the more agitation the solder sees, the more dross will be formed. A nitrogen blanket will prevent oxygen from reaching the surface of the solder and the dross generation will be greatly diminished or eliminated. There are also chemical dross reducing agents such as the Kester # 5744 Dross Eliminator. These chemical compounds react with the tin and lead oxides reducing them back to the base metal and releasing the oxygen to the air. Follow the instructions on the Product Data Sheet when using chemical reducing agents.
The term “dross” is used to describe waste material which must be removed and processed separately or discarded in a safe place. It may also be dangerous, poisonous, or impure, depending on the context of the usage. This word from from an Old German word meaning “dregs,” and it was originally used in reference to manufacturing processes. In the original sense, people used “dross” to refer to impurities which arise during the smelting process. As metal is melted, it oxidizes, forming a layer of scum and impurities which float to the surface as the metal heats up. This dross can be skimmed from the metal so that the refined product will be more pure, ensuring a reliable performance when it is cast or worked. With some metals, the amount of dross generated can be very high, as much as 50% of the metal, and this can drive the cost of the metal up significantly. In addition to containing the products of oxidation, the dross can contain a variety of unwanted impurities which have gotten into
