Tips for Soldering Copper Tubing: It Isn’t as Hard as You Might Think!

First, you must determine whether or not your town or city requires “licensed” professionals only, to work on copper tubing in your home plumbing system. If professionals are required by local regulations, you’d better call the plumber. Otherwise, here are some general tips and advice to help with performing basic copper tubing fitting and sweating.

Sweating copper tubing is not rocket science, although it does work under some fairly technical principles. Basically, it works on “capillary-action”, where the heat applied with a torch or other heating tool ‘pulls’ the solder material toward it, filling the space between the fitting and the tubing. When it cools, it creates a solid seal.

Tools needed:
-Safety glasses.
-Heat resistant work gloves.
-Fittings brush (wire brush that fits inside copper fittings); if not available, you can use emery cloth).
-Emery cloth (sanding medium)
-Wet rag (to clean joint when completed)
-Propane (or other fuel) hand-held torch
-Soldering “flux” (helps the solder flow and adhere)
-Flux brush (for applying soldering flux)
-Solder material–NOTE: be sure to use “lead-free” solder on ‘potable’ (used for drinking, cooking, washing, bathing, etc.) household systems.

Of course, depending on the actual job at hand, other tools may also be needed, such as a hacksaw or tubing cutter to cut copper tubing; bucket for catching drips if working on an ‘active’ line; ladder, etc.

Steps for a good soldered joint:
NOTE: BE SURE TO WEAR NECESSARY PROTECTIVE EQUIPMENT WHEN SOLDERING! At minimum, you should use:
-Safety glasses
-Heat resistant gloves
-Hard hat, if working in tight areas where you could bump your head.

Soldering copper tubing & fittings:

Clean, clean, clean!
-Using the “fittings brush” (or emery cloth), clean inside the fitting to be soldered to the tubing.
-Using emery cloth, clean the outside end of the tubing to be soldered (clean same length of the tubing as will fit into the fitting).
-Using the “flux” brush, apply a thin coat of “flux” on cleaned end of tubing and inside cleaned fitting.
-Press the fitting onto the tubing until it “seats”.
-Using the lit propane torch, heat the fitting, concentrating the heat of your flame toward the “center” of the fitting; i.e., apply the heat to where you want the solder to “flow to”. It also helps to move your torch (i.e., the flame) around the fitting so it heats as evenly as possible all around, thereby ensuring a complete seal all around.
-As you apply the heat, touch the end of your solder to the tubing (preferrably on the ‘opposite’ side from where you’re applying the heat), just where it comes out of the fitting. When the fitting is hot enough, you’ll see the solder melt and be drawn into the joint. When you see the solder fill the joint, remove the heat. Be sure to use enough solder so you see it fill all around the fitting/tubing connection.
-Using the wet rag (with gloves), carefully wipe the joint.

*CAUTION: Because the soldered joint remains hot, applying a wet rag can cause instant steam, which can cause skin burn. Be sure to wear the gloves for this step!

That’s it! Once finished and the fitting/tubing connection has sufficiently cooled (just moments), you’re ready to test the fitting for leaks. Slowly turn on the supply, and look closely at your newly soldered connection. If you’ve carefully followed these instructions, there should be no leaks!