Which step must be performed first to prep copper pipe for soldering?

• A. Burrs must be removed from the inside of the pipe using a wire brush
• B. The pipe is cleaned using sandpaper or steel wool until the surface shines
• C. Flux is applied
• D. A torch is used to melt the wire that solders the pipes together

Answer: (A)

Removing burrs from the inside of the pipe is the first prep step. When a copper pipe is cut, sharp edges can prevent the pipe from seating fully and create gaps where solder can leak. Deburring the inside smooths the edge, allowing solder to flow evenly into the joint and form a solid seal. After this, you would clean the outside to remove oxidation, apply flux to promote solder flow and protect against oxidation during heating, assemble, and then heat with a torch to melt the solder. Cleaning until the surface shines isn’t the initial priority, and applying flux or using the torch come after the burrs are addressed.