How to Sweat Copper Pipe

Soldering or sweating means joining two parts together with the use of solder or metal filler and the process of melting. This can be used for silver, electronic parts and copper. In plumbing, copper tubing is used by some homeowners. When copper tunings leak, this process can also be used.

Since copper tubing is designed to conduct heat away faster as opposed to hand-held soldering iron, propane torch is recommended. However, for smaller diameters of copper tubing, say 8mm or 22mm, electrical tool can be used to do the job.

In this particular guide, you will learn about sweating a copper pipe and we will be using propane torch. The process is relatively easy but still needs preparation, patience and skill. Not knowing the proper way to sweat or solder can lead to an unsuccessful DIY project.

Step-by-Step Process:

First, you need to gather the tools and supplies you will use for the process. These can be bought from your local hardware store.

Tools and Supplies Needed:

  • Propane Torch
  • Solder
  • Flux
  • Emery Cloth
  • Copper Cutter
  • Flame Protector Cloth
  • Goggles
  • Gloves

Step 1: Locate the leak.

It is important to find where the leak is before buying new fittings and tube. It is also important to turn off the shut-valve that supplies water through the pipe. If there is a local shut-valve, there is no need to cut the water supply from the main line. Once you have spotted the problem, you can now determine the size of the tube and fittings you need to buy.

Step 2: Prepare and assemble soldering tools.

The basic tool you need is a propane torch that comes in two types: with automatic igniter and manual igniter. The kit has a regulator and tip that that has to be attached to the small tank with a screw. If you have an automatic igniter, simply open the fuel adjustment valve and light the tip by pushing on the button. However, if you bought the other type, you have to buy a striker or match but it is recommended to invest in a striker since it is safer and easier to use. Simply squeeze the wire handle to ignite the gas.

For cleaning the copper surfaces while heating the joint, paste flux does the job. This material facilitates soldering and prevents oxidation and uneven surfaces. It also allows the solder to evenly spread as heat is applied. The emery cloth, on the other hand, removes the dirt and cleans the newly cut copper tube.

Wearing gloves is also important to prevent potential harm like burns and sparks. Goggles need to be worn as well to protect your eyes from being exposed to heat and flame.

Tip: Leaded solder is still available but it is best to use lead-free solder if you are going to work on a water pipe. Lead can leak through the pipe and contaminate your water supply.

Step 3: Cut the copper tubing.

With a tube cutter, you can now cut the copper tubing cleanly. To do this, you need to clamp the pipe between the guide wheel and the cutting wheel. Rotate the cutter, encircling the tube. Next, you need to tighten the cutter knob several times and rotate it until the pipe falls off. For plumbing use, you might want to buy a tube cutter that can accommodate up to an inch of tube. Conversely, if there is a need to cut a larger copper tubing, hacksaw can also be used. To avoid leaking, ensure to smoothen out the burrs from the saw teeth. And to be sure that the tube will stay in place as you cut, grip one end tightly while tucking the other end on under your knee. It is also best not to do the process quickly to avoid making a dent on the pipe.

Step 4: Clean off the burrs.

With the tube cutter and a ream tool, remove the burr inside the end of the cut tube. Insert the ream attachment and twist with one rotation. This is necessary to ensure water flow will not be decreased. If inside burr will not be removed, it can lessen the passageway of water.

Step 5: Clean the tubing.

After cutting, it is crucial to clean the ends with emery cloth to ensure sweating will be smooth and leaks will be avoided. This will remove corrosion and dirt. You will know when to stop when the copper pipe becomes shiny. Do the same procedure with the fittings you will attach to the tubing.

Step 6: Clean using fitting brush.

With the designated wire brush designed to fit in the tube, work on the inside of the fittings for cleaning. The emery cloth can also be used. Just wrap it on your finger and clean the inside. Be careful not to touch the already cleaned part with your bare hands.

Step 7: Apply paste flux.

With a brush, apply the flux evenly on the mating surfaces; the end of the pipe and the inside of the fittings. Afterwards, insert the fittings, all the way through until it fits securely.

Step 8: Start to solder.

First, heat the part that needs to be joined with the propane torch. Ensure that the joint is moved back and forth to ensure molten solder is evenly and completely applied. With the solder against the joint opposite the flame, wait for the solder to melt and flow. It should cover the joint. No need to wait for it to harden and you can solder the next joint right away since the molten solder will harden as the heat subsides.

Note: Ignite the torch and make adjustments on the flame until the blue cone is approximately 1-1/4 inch long. And since the hottest point of the flame is at the tip, ensure that it just touches the fitting. The solder, on the other hand should be on the coolest point, the opposite of the flame because it easily melts. Wait for about 30 to 45 seconds to put pressure on the joint. As for sweating the brass valve on the copper pipe, remember that you will need to apply heat longer.

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