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How To Solder Copper Pipe
Even with push on fittings sometimes the only way to repair a leaky copper pipe is to solder it. With a little preparation it isn’t difficult to solder copper pipe. The first thing to do is to get all of the necessary soldering tools and supplies ready.
The list of tools can be a little overwhelming but you really can’t improvise when it comes to soldering supplies. Once you have all the tools the following steps can show you how solder copper pipe.Continue to 2 of 8 below.
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Measure and Cut
Carefully measure the copper pipe before cutting. Take care to account for the amount of pipe that needs to fit inside the fittings. If the pipe is short and only a small amount makes it inside the fitting a proper fitting can’t be made. Use a copper pipe cutter or a hacksaw to cut the pipe.Continue to 3 of 8 below.
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CleaningClean both the pipe and the fitting thoroughly. To clean the pipe use a reamer or pocket knife to clean the cut edge of the pipe making sure to remove any burs. Clean the outside of the pipe with sand cloth. If you cannot see all the way around the pipe use a small mirror or inspection mirror to check the area you cannot and make sure it is clean.
Use a fitting brush to clean the inside of all the fittings. Without a clean pipe and fittings you most likely will not be able to get a leak free... joint. Try not to touch the cleaned pipe or fittings.Continue to 4 of 8 below.
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Setting UpTake some time to set up your work area and assemble the necessary tools. Safety first, make sure you have a spray bottle with water, flame protector (if needed), and fire extinguisher all within reach. No matter how small of project it is always best to be prepared because nobody expects an accident.
Before trying to solder make sure there is no residual water in the pipe. Many people believe you can boil the water out of the line with enough heat. This can sometimes work if the steam has a... place to go but often the water will seem to keep coming from nowhere and you will be burning a lot of gas for nothing.
Don’t try to rush this step, if you are still getting any amount of water out of the pipe do one of the following.
Continue to 5 of 8 below.
- Wait for it to drain.
- Disconnect a line somewhere to give the water another place to go to.
- Blow out the water.
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FluxingUse the acid brush to apply flux to the fitting and the pipe. Mix the flux before putting it on the fitting and pipe if it looks inconsistent. Be thorough and make sure you get a generous amount of flux all the way around the pipe. With both the pipe and the fitting fluxed put the fitting and pipe together.Continue to 6 of 8 below.
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HeatingLight the torch and apply heat to the pipe first. Then move the flame to the fitting and alternate between the two. As the copper heats up direct the heat toward the upper part of the area where you want the solder to flow, not just at the joint.Continue to 7 of 8 below.
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SolderingUse the end of the solder wire to test the heat of the copper and keep testing if it doesn’t melt. Once it starts to melt and draw in move the heat away toward the bottom of the fitting to avoid overheating. Apply heat back and forth around the fitting and follow it with solder overlapping it all the way around the joint.
The solder should flow smoothly when the fitting is hot enough. Once you have a nice ring of solder all the way around the joint pull the heat and solder away and shut the torch... off.
Note: Too much solder can be a bad thing. Just make sure there is solder all the way around the fitting and then inspect.
Tip: Putting a bend in the end of the solder will make getting all the way around the fitting easier.Continue to 8 of 8 below.
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Testing The JointInspect the fitting all the way around and you can sometimes see where the solder did not flow into the joint. If you see a place like this try soldering that spot again before testing it with water. If everything looks good then turn the water on and test it. You should know right away if it’s leaking just by looking at the fitting because copper does not hold leaks well.