Arkansas HVACR NewsMagazine May 2022

HVACR NewsMagazine May 2022

Tech News

In cases where you are brazing copper only, you will want to make sure you have a flux- coated phosphorus-bearing rod. In this copper-to-copper application, the phosphorus acts as the fluxing agent, so no additional flux is required.

Brazing or soldering metals other than copper

When you are brazing steel or brass, you do NOT want to use an alloy that contains phosphorus. Instead, use a flux either applied onto the base metal or contained in or on the rod. When brazing steel, use a flux-coated rod with high silver content (45-56%); you may also consider using an external paste flux if you don’t have flux -coated rods. Brass also works well with high-silver flux-coated rods, though you may alternatively use external chemical flux. special consideration. When bonding copper to aluminum, use a special rod for that metal combination, as the difference in properties of aluminum and copper requires special care. AL-COP by Solderweld is an example of a good brazing rod for copper-to-aluminum bonding. When you braze, you heat the base metal rapidly, which can cause oxides (or a blackish scale) to form when the metal reacts with oxygen at a high temperature. Oxides also weaken the bonds and can cause potential leak issues down the line, so we can displace the oxygen inside the system lines by flowing nitrogen while we braze. Dissimilar metals will have Flowing nitrogen