What should be done to the tubing around the copper prior to assembly?

• A. Fitted snugly around the copper tubing; Do not overtighten
• B. Left loose around the copper tubing
• C. Bent around the copper tubing
• D. Heated before assembly

Answer: (A)

In brazing and soldering, the joint depends on close, intimate contact between the tubing and the fitting so capillary action can draw filler metal into the joint and form a strong fillet. The tubing around the copper should be fitted snugly and lightly to the fitting, without being overtightened. This snug fit ensures there are enough contact surfaces for the filler metal to flow evenly and fill the joint completely, preventing gaps that could lead to leaks or weak spots.

Leaving the tubing loose creates too much clearance, which disrupts capillary action and can leave voids or leaks. Bending the tubing around the fitting can kink or deform it, compromising flow and the seal. Heating the tubing before assembly isn’t the proper step for fitting— cleaning and preparing the surfaces and then assembling so they fit snugly is the right approach; heating is done as part of the brazing process itself, not beforehand, and premature heating can alter dimensions or cause oxidation.

So, ensure a snug fit around the copper and avoid overtightening to achieve a reliable, leak-free joint.