How to Solder Copper Tubing on an AC Compressor

Soldering (or sweating, as it's commonly called) copper pipe is the process of melting liquid metal to form an airtight or leak proof connection between two joints. Applying open flame from a torch to the solder will seal up the joints in the point and prevent any freon from leaking out of the AC unit. The other ingredient to making a successful joint of copper tubing is using the flux, which will help the solder to adhere to the copper before it oxidizes.

Step 1

Measure and cut the copper pipe to the appropriate length needed to connect to the AC compressor.

Step 2

Sand about two inches of the end of the copper pipe and inside the connector. Sand until you can see the new, shiny copper metal.

Step 3

Apply flux to the end of the copper pipe and to the inside of the connector. Apply an even coat around the outside end of the pipe and the inside wall of the connector. Slide the connector onto the end of the pipe.

Step 4

Turn the flow of propane to the "On" position on the torch and light the flame with the lighter. Heat the pipe and connector with the flame until you see the flux bubble. Apply the solder to the opposite side of the pipe where the flame is, and the heat from the flame and pipe will draw or suck the solder into the connection, sealing it. Move the solder around the pipe as you heat it, ensuring the solder is all the way around the pipe's connection. Wipe off any excess solder with the emery cloth.

Step 5

Turn the flow of propane off to the torch to extinguish the flame, and allow the pipe and connector to cool. Repeat the above steps to solder any additional copper joints.


  • Avoid the use of a propane torch around flammable items as this could result in a fire or explosion.
  • Always solder in a ventilated area.
  • Never touch the end of a propane torch as this is several hundred degrees and can burn the skin.
  • Never leave the gas flow on when the torch is not in use.
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