Hard Welding Copper Pipe This technique is required for pressurised systems such as refrigerators and air conditioning units. We will explain brazing, which is a type of welding is used in refrigeration and air conditioning systems. We use this type of brazing instead of soldering
because of the higher pressure and higher temperatures. To perform this type of welding we will need: Copper refrigerant piping, fittings for the relevant joints, copper rods to form the joint, flux to prevent the joint area oxidising, and a pipe expander for making junctions without using fittings. To perform the actual weld we need an oxybutane brazing kit. The tools we need for cutting the pipe are a tape measure and a copper pipe cutter. Emery cloth for cleaning the pipe and a permanent marker to mark it up. Finally, to light the torch, we need a flint spark igniter. For safety, we need gloves and safety glasses. Demonstration First we put on the safety gloves and the welding goggles. Once we’ve cut the tubes, put them in the vice in
the arrangement needed for the installation. Hold them firmly in the vice. Finally, light the torch with the flint spark igniter. Adjust the mixture of oxygen and butane to achieve
the ideal flame for brazing. This type of flame is characterized by burning blue
with a distinctive sound. Once the area to be brazed is hot, warm the copper brazing
rod and dip it into the flux. We dip it into the pot of flux to prevent the joint
oxidizing later. Once the area to be brazed is at the right temperature,
we apply the brazing rod and weld the joint. We can tell the ideal temperature for the joint by the characteristic cherry red colour.