How to Use Silver & Tin to Solder

Tin and silver alloys were developed to replace lead in soldering projects for food and beverage containers that must be lead and cadmium free. Tin and silver solders flow at moderately high temperatures to create greater strength in the overall components.



Tin and silver alloys usually contain 3.5 to 6 percent silver. They are high strength solders, with higher creep strength than tin/lead solders. Tin and silver alloys work well with both ferrous and non-ferrous alloys including stainless steel, nickel, copper and brass. The temperature melting point for a tin and silver alloy is 430 degrees Fahrenheit. The temperature flow points range from 430 degrees to 536 degrees. Higher amounts of silver will raise the fluidity point of the solder.

• 1

  Secure the work so that it cannot slip or move during the soldering process. Holding frames are available for electronics projects. A clamp or vise will work for steadying the joint in other applications.

• 2

  Make sure that all parts are completely clean, including the tip of the soldering iron, if you are using one.

  A small hand-held file works well to remove grease and oxidation from the two places to be joined. An emery cloth is another cleaning device. There are also abrasive rubber erasing blocks that work well to clean surfaces. Fiberglass filament brushes can also remove minuscule debris, but use with caution to avoid skin contact, because they are highly irritating if touched. The soldering iron itself should be "tinned" before using to ensure an easy and timely flow of solder at the joint. Tinning is accomplished by applying a thin layer of solder to the tip of the gun, and then wiping it on a damp sponge. Another option is a paste-like product called tinner to dip the tip of the iron into before using.

• 3

  Raise the temperature of the two metals to approximately the same level for the solder to flow before creating the solder joint. Flux is always required, and there are different fluxes for different metals. The flux must be applied to the joint before the solder. If the solder being used has a flux core, no additional flux is necessary. When the flux is in place, apply and heat the solder itself until it flows. Use just enough solder to bond the two metal parts. The whole operation takes only a few seconds, with time variances depending on the size of the joint and the flow point of the solder.

• 4

  Return the soldering iron to its stand to cool--after the solder flows--and the solder joint should not be moved until it is cool.