How To Solder Capillary Joints

1 Measure and Cut

Carefully measure the length of pipe needed, allowing extra for the entry into the fitting. With the pipe held securely – but don’t apply so much pressure that it is distorted – cut the pipe squarely with a fine-toothed hacksaw, or rotate a pipe cutter around the tube.

2 Adding Flux

Copper must be clean and grease-free for a perfect soldered joint, so flux (a chemical cleaner) is applied to the metal to make a barrier against oxidization until solder is applied. Coat the ends of the pipe and fitting with flux then push the pipes into the fittings up to the stop.

3 Remove Burrs

Remove burrs on the cut end. Some makes of pipe cutter have a blade at the end to remove burrs, but if you’ve cut the pipe with a hacksaw, remove the burrs with a round file. Clean the outside with a file, making sure the ends are square. Clean the end of the fitting.

4 Apply Heat

For an integral ring joint, play the flame of the torch evenly around until a bright ring of solder appears at each end. For end-feed joints, heat the flux until it bubbles, then touch the end of the solder wire around the mouth of each sleeve until a bright ring appears all round.

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