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Soldering Copper Pipe

The following article is for informational purposes only, and in no way is a replacement for a professional’s knowledge and expertise. Readers are reminded to always follow all codes and laws within their community. Use of this information is at your own risk. 

Always have both a fire extinguisher and bucket or spray bottle of water nearby, and ALWAYS wear proper protective attire, especially safety goggles and gloves.

How to solder a copper pipe:

Tools & materials needed:

1. Propane torch (a Bernzomatic with one click lighting is very handy for quick start and shutoff of the flame)
2. Flux for lead free solder
3. Lead free solder.
4. Emery cloth/wire brush/copper pipe cleaner
5. copper pipe tubing cutter
6. copper pipe and joint pieces
7. Flame protector shield
8. Pipe wrench (to hold pipe in place)

Before you begin the process, make sure all water has been drained from the section of pipe you are working on.  Make sure your main water valve as well as the valve closest to where you will be working are both functioning properly.  Any water in the joint you are soldering will prevent the solder from flowing properly and the result will be a leaking joint.

1. Make sure anything flammable near the area is removed.  If working near joist or stud, mist wood lightly with water (while keeping pipe dry).  Place flame blanket or other flame protection on the joist or stud to protect it from flame.

2. Cut copper pipe to size with tubing cutter, keeping cutter straight, and tightening every couple turns to keep pressure on the blade.  Be very careful not to cut yourself on the ultra sharp blade. Rotate cutter around until pipe cut is complete. 

3. Clean both ends of the copper pipe as well as any joints to be used.  Using a combination of the copper pipe cleaner, emery cloth,and wire brush, clean both the outside and inside of the pipe until it is nice and shiny (to the approximate depth of the joint), as well as free of any debris.

4. Take flux and apply to outside of pipe and inside of joint.  Make sure the entire joint is covered, as this greatly enhances the flow of the solder.

5. Now we are ready to apply the solder.  Unroll about one foot of solder, and bend the top 1-2″ so it forms an upside down “J”. Solder will always flow toward the heat.   The goal is to heat the joint where most convenient/safe, while keeping the solder on the other side of the joint.   For example, if thinking of the joint as a “clock”, if the tip of the flame is on the bottom half of the joint at 6:00, the solder itself would be at approximately 12:00.  Turn your flame on, and start by heating the joint for a few seconds first.   Then touch the solder (while holding it by the roll) to the joint, away from the flame until it fills the joint.  As it is flowing, carefully move the flame ever so slightly back and forth.   Do not place solder directly in flame, and be very careful that hot solder does not drip on your hands/arms/cloths or other body parts.  When you can see the joint is filled, shut the flame off, and allow to cool.  If you want the joint to look clean, you can VERY CAREFULLY (while wearing cloves) take a wet cloth and wipe the joint as soon as you turn the torch off.  Using the wet cloth, quickly wipe in circular fashion around the joint and eliminate any drips of solder.  Then allow pipe to cool fully.   Be very careful to NOT touch the hot pipe with any part of your body, it will give you severe burns.  Repeat for other joints, being careful to not overheat the newly soldered joint and cause a leak.

Tip:  Always fit all pipes first before soldering.  Then, mark carefully all angles with marker (but above area actually being soldered so as not to interfere with the joint).  Assemble and solder as many joints as possible at work bench area, as it is much easier to make a good joint when not working around obstacles.  Then after fully cooled, take assembled piece to final location and solder the last joints in place. 

6. Turn water back on slowly, and with faucet open to bleed air out of line.  Watch for leaks.  After air is out of line, increase pressure to normal level.  Check for leaks.  Even if you see nothing for the first few minutes, keep checking.  A leak can appear hours later in a joint you thought was perfect if there was fleck of dirt present and it breaks loose from pressure.