Refrigerant brazing is the process of joining copper tubing using high-temperature filler metal while protecting joints from oxidation, creating reliable connections for refrigerant circulation. Proper brazing prevents leaks that reduce cooling capacity and require costly repairs.
Brazing Process
Copper tubing connections are cleaned with emery cloth to remove oxides, then fluxed with specialized brazing flux. Heat is applied with oxy-acetylene or propane torches to 1100-1200 degrees Fahrenheit, allowing silver solder (45-50 percent silver content) to flow into the joint by capillary action. Proper joint geometry with 0.015-0.035 inch clearance ensures complete filler metal penetration. Each joint requires 2-3 seconds dwell time under heat for complete wetting and flow.
Quality Standards
Brazed joints must withstand 350-400 PSI working pressure (per EPA requirements for refrigerant systems) without leakage. Poor technique causes joint failure, contamination, or nitrogen escape during evacuation. Joints must be inspected for complete filler metal coverage and smooth appearance. All brazing must occur with nitrogen purge flowing through tubing to prevent oxygen contamination and oxidation that reduces joint integrity by 50-70 percent.