Put on the safety glasses and rubber gloves. Set the two-quart pot on a table or bench. Light a propane gas burner and set it to medium-high heat.
Flux is a material that is used to remove oxide film from metal. One application for flux is the soldering of metals such as copper. To make your old solder, mix ingredients with water which is boiled away. The result is a powder that you can use to coat the metal that you want to solder. Materials for the flux need to be used outdoors or in an area that is well-ventilated.
Pour one quart of distilled water into your two-quart pot. Add seven tablespoons of boric acid, four and a half tablespoons of sodium phosphate and five tablespoons of borax to the water. Stir the ingredients as you add them to the pot.
Set the two-quart pot on the burner and allow it to come to a boil. Stir the contents of the pot often until it reaches a boil.
Remove the two-quart pot from the burner. Turn off the gas and then set the two-quart pot aside to cool. The flux will begin to harden as it cools.
Transfer the flux in the two-quart pot into a glass far. Allow the flux to completely cool before placing the lid on the jar.
- "The Art of Soldering;" R. Brewster