A DIY Guide to Soldering Copper Pipe
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A DIY Guide to Soldering Copper Pipe

Soldering copper tubing and pipe is as much an art form as it is a skill but it is an art form that anyone can master with a little patience and practice. Although you can learn to solder copper pie successfully in as little as an hour or two, practice, practice, practice makes the job go quicker. Preparation the cutting and dry fitting of all the copper pipe and fittings before you soldier the first joint is the first key to doing the job successfully the first time. Before I get into cutting and dry fitting the systems components, let us discuss the tools and materials that you will need to do this job. Basic tools for working with copper pipe and fittings. 1.) Measuring tape. A 25-foot locking tape is a good tape to start with. 2.) Plumber’s torch. A propane torch with an electric start head is a good choice. 3.) Tubing cutters. One standard size cutter and one for working in close quarters. 4.) A hacksaw 5.) A tubing brush 6.) Flux brushes 7.) Channel Lock pliers. Channel Lock is the is a brand name and trade name for tongue and groove pliers. 8.) Screwdrivers Basic supplies that you will need. 1.) Lead-free plumber’s solder 2.) Paste soldering flux 3.) Emery cloth 4.) BernzOmatic Heat Cloth 5.) Rags Material that you will need. 1.) Copper pipe (Type and size determined by job). 2.) Copper fittings (Type and size determined by job). Every plumbing project that you undertake will require different materials but the procedure for working with them will be the same. For this basic tutorial, we will be replacing an older, electric hot water heater with new, energy efficient one. Removing the old hot water heater. 1.) Shut off the branch circuit breaker feeding the heater. 2.) Using a non-contact circuit checker, verify that the circuit has been shut off. 3.) Disconnect the wires at the hot water heater. 4.) Shut off the water inlet valve. 5.) Open all the cold water taps throughout the house and then drain the tank. Connect a garden hose to the drain valve and drain it in a laundry sink or some other appropriate area. 6.) Once the tank has drained completely, allowing time for the water in the cold water pipes to drain back into the tank, cut the copper pipes as near the top of the tank as possible. 7.) Remove the old tank and store for proper disposal. Installing the new, energy efficient hot water heater. 1.) Place the unit in position. The first thing that you notice is that the new unit is several inches shorter than the old one was so we are going to have to extend the hot and cold water lines. Let’s begin. 2.) Measure the diameter of the old copper pipe. The copper pipes attached to the hot water heater will be either ½” or ¾” in diameter. As you can see from this chart, ½” and ¾” are nominal sizes and the actual size varies considerably.

Nominal Size

Outside Diameter

Inside Diameter




























If you have any doubt about the pipe size take a piece with you to the home center and match it up.

3.) Measure carefully to determine how much new pipe you will need. It is not recommended that you use the old fittings (elbows, shut-off valve, etc.) so measure beyond those fittings. You cut the pipe to length when you get it and the new fittings home and are ready to install them.

4.) Now that you have all the required fittings, pipe, tools, and other supplies close at hand you are ready to begin. At this point, you need to shut off the water supply to your home because you will be removing the old cold-water shutoff valve at the heater location. Once the water supply is shut off place a bucket under the valve to catch the water remaining in the pipe. You do not need to disassemble this valve because you will not be reusing it.

5.) Using your propane torch, heat the feed side of the old valve while grasping it with a pair of Channel Lock pliers. Apply the heat evenly by moving the flame all around the valve. When the old solder melts twist the valve with the pliers breaking it free, and then pull it off the pipe. Using a wire brush brush as much of the old solder as possible from the pipe while the solder is still in a molten state. 6.) Repeat this procedure to remove the old elbow from the hot water line feeding the house. Remember you are replacing this elbow with a new elbow. Reusing old copper fitting is asking for trouble. 7.) While the pipes are cooling off, disassemble the new valve. Never sweat solder a valve without first removing its guts because the intense heat will destroy valve washers and packing. 7.) Using a piece of emery cloth, clean the outside of the old pipes until a bright copper finish appears. Make sure the cleaned area extends at least ½” beyond the end of the fitting after it is slid over the end of the piped. Solder, no matter how much flux you use, will not bond properly to dirty copper. Remember, if there are leaks and you have to remove a fitting to redo the joint, you will have to use another new fitting and that’s wasted money. 8.) Slip the new valve body and elbow in place. 9.) Measure and cut two lengths of copper pipe so they fit snugly between the fittings on the hot water heater tank and the elbow and the shutoff valve. By snugly, I mean that the pipe is fully seated in both fittings. This is called dry fitting the pipe and fittings. 10.) Once everything fits together properly, disassemble them. Clean the inside of the valve inlet and outlet with a wire brush. Do the same for the fittings on the tank and with the elbow. Now we are ready to reassemble and solder. We will begin with the feed side. 11.) Using a flux brush, apply a thin coating of flux to the outside of the pipes and to the inside of the pipe fittings. The flux not only assures a good bond between the copper pipe and the solder, it prevents the copper from oxidizing when heated. Oxidation makes for a very bad bond between the solder and the copper if it bonds at all. Remember a bad bond mean a leaky joint. 12.) Reassembled the fluxed pipe and fittings. 13.) Now apply heat to the pipe and fitting. Position your torch so that the tip of the light blue inner flame just touches the pipe. This part of the flame is the hottest and will bring the pipe and fitting to soldering temperature. Watch the flame touching the pipe on the side away from the torch, when it turns green the pipes has reached soldering temperature. Now remove the heat and apply solder to both ends of the fitting. If the joint was properly heated, the solder will flow evenly into the joint by capillary action. 14.) For a professional appearing joint, wipe the still hot joint with a wet cloth. 15.) Repeat steps 11 through 14 for the hot water discharge side of the tank. 16.) Once the pipes are cool to the touch. Reassemble the shutoff valve, close the valve, close all the water taps that you had opened earlier, and then reopen the shutoff valve on the main water supply. 17.) Open the tank valve and check for leaks. No leaks! Great job! 18.) Wait. We’re not done yet. Reconnect the electrical feed and turn on the CB (Circuit Breaker). Now we are done.

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