How to Make a Flare Fitting

copper piping
  • 1-5 hours
  • Intermediate
  • 0-200
What You'll Need
Tube cutter
Adjustable wrench
Flaring tool bar
T-bar flare press
Abrasive clean up strip
Flare nut

A flare fitting is a method of joining copper piping to a threaded fitting, usually of brass. It is a compression joint which is formed without using any heat, unlike a soldered joint. The flare fitting forms an extremely reliable and strong joint.

Step 1 - Cut the Pipe End

Use the pipe-cutter to cut the end off the pipe. Put the pipe inside the cutter and gently screw the cutter down until the circular blade is resting on the pipe. Remember that copper is a soft material and if you screw down too hard, you will bend the pipe. Gently rotate the cutter round the pipe—it will score the pipe. Screw down a little more and rotate again. Each time you rotate the cutter, its blade cuts a little deeper into the pipe. Continue to do this until you have cut through the pipe. Clean the pipe-end with the abrasive strip. It should be shiny and free from any burrs.

Step 2 - Flare Nut

cutting copper pipe

Slide the flare nut onto the pipe—make sure when you do this that you have not put it on upside-down. That is, once you have flared the end of the pipe, the nut needs to screw onto the fitting. If you put it on the wrong way you will need to cut the end of the pipe and start all over again. It will not come off over the flared end.

Step 3 - Tool Bar

Put the pipe-end into the flaring tool bar. The flaring tool bar is the long bar with a number of holes in it and two wing nuts that allow it to open and close. The diameters of the holes are marked on the bar. Choose the same diameter as your pipe, open the bar, put in the pipe and tighten the bar up. The end of the pipe must be 1/8 inch above the surface of the bar. This is the part of the pipe that will be bent in order to make the flare fitting. At this stage it is useful if the tool bar can be clamped or otherwise made secure on your workbench.

Step 4 - Flare Press

flare tool

Now use the flare press—the tool with the t-bar for tightening. This is the tool, sometimes called a mandrel, and it is what actually makes the flare fitting. You will see that the centre of the press is a heavy, ribbed, cylindrical cone. Place the point of the cone gently in the centre of the pipe and begin gently screwing it down into the pipe, using the t-bar. As it moves down, it will bend the pipe out into a flare.

Step 5 - Check the Fitting

Take the pipe out of the bar, check that it is smooth and has no cracks, slide the flare nut up and screw the flare fitting onto the fixed threaded point. Tighten it up with a wrench. You have successfully made a flare fitting!