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Flare Fittings

The flare type fitting is not as widespread as it used to be, but still has it's place. This style fitting is most likely to be found on either fuel oil line or gas appliance line. Some older mobile homes and even campers have used this style for domestic water. In various places at various times, it has also been used in regular homes for domestic water too.

The type of pipe that is used for flare fittings is soft copper. Soft copper is easily bendable. If you force regular hard copper to bend, it will just kink(and it would be very hard to do). Soft copper is easy to work with and gets attached with either compression or flare fittings. There are a variety of flare fittings available. Here, we will be dealing with the procedure of making the flare on the pipe itself.

In order to make flares in soft copper, you need to have a flaring tool. The picture to the left is the required tool.

The basic idea of the flare style fitting is to spread out(or flare) the end of the pipe at an angle. This angle also matches the fitting. The nut and threads of the fitting are only to apply pressure to the flare portion of the copper against the fitting. This makes the seal. The threads don't actually do any sealing.

The first step is to put the nut on the pipe, so that after the flare is made, the nut can be slid into place over the flare and screwed onto the fitting. The nut can't be put on after the flare is made. You wouldn't be the first person to make a flare and forget to put the nut on.

The bottom piece of our tool has a series of holes for different size pipe. They normally go by outside diameter. It acts as a clamp to hold the pipe, and each hole also has the flare angle in it. In the picture to the right, you can just see the flare section of the tool.

What is also very important is the amount of pipe the protrudes from the tool. This is the amount of pipe that will get bent outward to make the flare. If there is too much, the copper can crack due to being stretched too far. If there isn't enough, the flare may not be wide enough to safely be retained by the nut, causing the pipe to come out of the nut and cause a leak.

This may take a few times to get correct. To double check, slide the nut over the flare and look in at the flare. If it takes up the flare portion of the nut without cracks in the copper, it should be a good flare. About 1/8" is a good guideline for the amount to have stick out.

When the flare is finished, it should look like this.

This is how the fitting goes together. You can see how the flares match up. The nut can be tightened quite tight. This will also help shape the copper to the fitting if there are any differences in the angles.

Free Online Plumber does not warrant any of the information on this page, in regards to the accuracy or effectiveness of these procedures or this information. Always check and follow all applicable local plumbing codes.
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