What Is A Flare Fitting? (A Great Solution For A Difficult-To-Solder Joint!)

You’ve probably heard of compression fittings, but what is a flare fitting? Like compression fittings, are useful in places where it’s difficult to solder a joint.

So, it’s a handy solution for hard-to-solder situations involving flexible (not rigid) copper. That’s why I’m going to tell you how to create and use a flare fitting.

What is a Flare Fitting?

A flare fitting is a type of compression fitting in which a flare nut secures the flared tubing’s tapered end to create pressure- and leak-resistant seals.

Flare fittings work only on soft metals, such as soft steel, flexible (or soft) copper, and aluminum. No heat is required to make the tube flare. The benefit of a flared fitting is its long-term reliability, and it is used as a solution for hard-to-reach locations.

How to Use a Flare Fitting

Keep in mind, you can only use flare fittings with flexible copper tubing, not on a rigid copper pipe. And unlike compression fittings, a flare fitting requires a flaring tool.

This 2-piece tool reshapes the end of the copper pipe, “flaring” it to fit into a special flare fitting. Sometimes, the tubing splits while being flared, so, if possible, make the flared connection first, then cut the tubing to length.

To get started, you’ll need a flaring tool and 2 adjustable wrenches. It will take you about 30 minutes to join 3 pieces together in a union if you have some flaring tool experience. If not, expect it to take longer as you learn how to use the tool.

1. Flare the Tubing Ends

• Sliup the flare nut on before you flare the end of the tubing.
• Choose the hole in the flaring block that matches the outside diameter of the flexible copper pipe.
• Clamp the tool onto the tubing.
• Alighn the compression cone on the tubing’s end and tigthen the screw.
• As you turn the handle, the cone flares the tubing’s end.
• Inspect your work carefully after removing the tubing from the block.
• If the end has split, cut off the flared portion and repeat the process.

2. Assemble the Pieces

• Seat the flare union against one of the flared ends of the tubing.
• Now, slide the nut down, and hand tighten.
• Do the same on the other side.

3. Tighten & Test

• Place one wrench on the union and one on a nut.
• Don’t overtighten a flared joint.
• Once snug, give each nut a half-turn.
• Turn the water on and test.
• If the joint leaks, tighten it carefully until the leak stops.
• If the leak persists, dismantle the joint and examine it to see if the tubing was cut squarely. Also, make sure that the nut was not cross-threaded on the fitting. Finally, anchor or support the tubing with 2 feet of either side of the flare fitting. One or all of these should stop the leak.

Final Thoughts

For beginners, this type of fitting might not be up your alley. However, it’s not as difficult as it sounds if you have an intermediate amount of plumbing aptitude or experience. But it’s a great skill to learn as it can be quite useful for joining a flexible copper tube in a difficult-to-reach location.

Related Resources

• What do you know about pipe fittings?
• How to use compression fittings
• Learn how to work with flexible copper tubing
• Sweating a pipe: step-by-step guide
• How to solder copper pipes safely
• Copper vs PEX pipe
• 5 main types of plumbing pipes

Call 1-Tom-Plumber

Don’t hesitate to contact us here or call us at 1-Tom-Plumber (1-866-758-6237) if you need help with fittings in your plumbing project.

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