How to Install Copper Tubing Flare Fittings

How to Install Copper Tubing Flare Fittings.
A flare fitting on the end of copper tubing provides a strong connection to a fixed point with a threaded nipple. You will need soft copper tubing and specific tools made for this purpose to accomplish the job. It is important to use flare fittings when you are dealing with high gas distribution or a lot of water pressure going through a pipe. These steps help you to be able to install that fitting.

Step 1

Cut the end of the tubing square using a hacksaw or a tube cutter.

Step 2

Slip the flare nut onto the end of the copper pipe. Move it back out of the way to allow for working room.

Step 3

Place the base of the flaring tool around the copper tube at the appropriate diameter size.

Step 4

Attach the flare cone over the copper tube opening using the screw fitting. Tighten this down until the cone is firmly seated inside the vise base.

Step 5

Remove the copper tubing from the base and examine the ends for splits. Bring the nut back up to the end of the flared tubing.

Step 6

Verify that it fits snugly in the bottom of the nut. It will still be loose at this time. Now you are ready to attach the end of the flared copper tubing nut to the end of the threaded nipple. Do so.

Step 7

Pressurize the line and check for leaks.

Things You Will Need

  • Flare nut
  • Flaring tool
  • Copper tubing
  • Wrenches
  • Tube cutter


  • Flare fittings are very expensive, but they will pay for themselves on projects where you need to be sure you have the absolute best resilience possible.
  • On gas lines-both natural and liquid-it is often advised to use Teflon tape at the connection on the nipple to provide an air and water tight seal.


  • If the flare is uneven or rough, cut the end and redo the cut.
  • If you over tighten, you will cause splits in the end of the copper tubing. Remember, the copper tubing is soft.

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