Working with Copper Pipe

Working with Copper Pipe

A properly soldered (or "sweated") joint on copper pipe is as strong as the pipe itself. A poorly soldered joint will leak. Work systematically because each step depends on the previous one: The pipe must be cut straight and all burrs removed. The inside of the fitting and the outside of the pipe must be clean. Flux must be applied for the solder to adhere. The solder must be fully drawn into the joint.

Pipe ends and fittings must be perfectly round. If either is dented or even slightly flattened, it is all but impossible to restore the original roundness. Cut the pipe again or buy a new fitting.

Cutting with a tubing cutter ensures roundness. If space is tight and you must cut with a hacksaw, do it slowly and gently. If you must bend a pipe to move it away from a wall, work carefully.


About 15 minutes to cut a pipe and join a fitting

Felt-tip marker, tubing cutter or hacksaw, multi-use wire brush, flux brush, propane torch (preferably with a trigger igniter), fiber shield

Cutting pipe, soldering

Protect any flammable surfaces with a fiber shield or cookie sheet.

Copper pipe and fittings, flux, solder (95 percent tin for drinking water supply), damp rag

Step 1

Hold a pipe in place to measure for a cut or use a tape measure. Take into account the distance the pipe will fit into the fitting. Mark with a felt-tip marker or a pencil.

Step 2

Use a large tubing cutter or a small one if space is tight. Align the cutting wheel with the cut mark. Twist the knob until the wheel starts to bite into the pipe. Rotate the cutter once, tighten a half turn or so, and repeat until the pipe is cut. Assemble all the parts of a joint in a dry run.

Step 3

Using a wire brush made for the size of the fitting, ream out every inside opening until it is shiny. Oil from your hand may weaken the joint. If you accidentally touch a brushed opening, ream it again.

Step 4

Brush or sand the outside of the pipe to be joined until it shines by inserting the pipe end in the multi-use brush and spinning the brush a few times. Rebrush or resand if you touch the shiny area.

Step 5

Using the flux brush (it often comes with the can of flux), apply flux to all the inside openings of the fitting and to the outside of the pipe. Take care to keep the flux brush away from any debris; clean it if any particles stick to it.

Step 6

Ignite a propane torch and point the flame at the fitting near the joint -- not at the pipe and not at the joint. The tip of the blue portion of the flame should just touch the fitting. Move the flame back and forth so you heat two opposite sides of the fitting.

Step 7

When the fitting starts to smoke, remove the flame and touch the tip of the solder to the joint. If it does not melt, heat again. Once the fitting is hot enough, the solder will be drawn into the joint. Move the solder around so the entire joint is soldered.

Step 8

Immediately repeat the process for any other joints in the fitting. This will go quickly because the fitting is already hot. Once all the joints are soldered, quickly wipe all the joints with a damp rag. Avoid bumping the fitting for 10 to 15 minutes.

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