Brazing Basics and Tips

HVAC School - For Techs, By Techs

In this podcast episode, Bryan talks about brazing basics and tips. He goes over safety, regulator settings, torch positioning, flowing nitrogen, heat control, and more.

Whenever you're going to be working with equipment that creates fire, you will want to make sure you know all of the safety procedures and have appropriate PPE. Make sure your gear is in really good condition; make sure your hoses and regulator have not been damaged. Be sure to have a fire extinguisher handy as well. When preparing copper lines, you'll want to keep things out of them. Make sure oxygen, dust, burrs, and flux can't get into the tubing.

Flowing nitrogen is a best practice, but it's also a staple among the brazing basics. Nitrogen displaces refrigerant, water, and oxygen that might be in the copper lines. Regulators can help you purge with nitrogen at somewhat higher SCFH (20-50) and then flow it at a very low SCFH (2-5). You should hear just a whisper of nitrogen when flowing it.

When you set up your torches, it's important that you look at the torch manufacturer's specifications. The tips have different designs for different functions, and it would be wise to read up on their purposes. When setting the oxygen and acetylene pressures, try to keep the numbers the same. Light acetylene first and THEN add the oxygen, and then you'll want to turn off the oxygen first and then acetylene. You'll want a neutral or slightly carburizing flame but not an oxidizing flame.

Bryan also covers:

• Protecting the workspace
• Unsweating
• Reaming copper
• Reducers, fittings, and swaging tools
• Nitrogen flow regulator types
• Wrenches for opening tanks
• Brazing vs. soldering
• Brazing/soldering rods
• Getting the copper hot enough
• Preventing carbon buildup
• Leak testing joints