Step 3 · Deburr and Clean
After cutting, a small ridge of copper, known as a 'burr', will be left on the inside edge of the pipe. Use a deburring tool, or the triangular reamer often found on the back of a tubing cutter, to scrape away this ridge until the inside is smooth. Next, you must thoroughly clean the outside of the pipe end (about 1 inch back from the end) and the inside of the copper fitting. Use a strip of emery cloth for the outside of the pipe and a specialized wire fitting brush for the inside of the fitting. Scrub both surfaces vigorously until they are bright, shiny, and the color of a new penny. This is the most critical step for a successful solder joint, as solder will not adhere to dirty or oxidized copper.