Solder Alloys
The Torrey S. Crane Company uses virgin grade tin, lead, silver, bismuth, cadmium, copper, antimony, and indium as principle alloying elements. Formulations can range from pure metals (pure tin, pure lead) to alloys composed of four or more elements (tin, lead, silver, bismuth, antimony, cadmium, indium, etc.). In addition to “standard” alloys, which are commonly used in particular industries, we also have the ability to formulate alloys in accordance with your special requirements.
The word “solder” describes a wide range of alloys which display relatively low melting points and are commonly used for joining or patching other, more resilient metals. Solders are normally grouped into two categories, depending upon their tensile strengths and melting temperatures.
Soft solders are normally alloys of tin and lead, and can also contain other metals such as antimony, bismuth, cadmium, copper, indium, and/or silver, depending upon the properties required by a particular application.
Hard solders, by contrast, are normally alloys of silver, copper, zinc, and phosphorous, and have much higher melting temperatures and tensile strengths. Hard solders are also known as brazing alloys.
While the process of soldering can vary widely depending upon the application, the process of soldering a joint usually begins with a thorough cleaning of the parts to be soldered by physical (scrubbing, brushing, sanding) or chemical (the use of a flux) means to remove surface oxides. Once the parts to be soldered are sufficiently cleaned to allow a viable joint, the parts are heated with either a soldering iron or torch to above the melting point of the solder. The solder, and possibly a flux, are applied to the surfaces and allowed to melt. When the heat source is removed, the assembly can cool to allow the new joint to solidify. A proper solder joint should exhibit no “gapping” or “pooling” of solder, which should spread through, between, or around the pieces that have been joined. If a flux is used in the above process, the oxides are removed by chemical means as heat is applied.