A good flare is very important if a solid, strong, leakproof joint is to be made at the flared connection. Tubing flares are made with special flaring tools. Some flares are made which have a single thickness of the tube forming the flare, other flares are made which provide a double thickness of metal in the flare surface.
The double thickness or "double flares" as they are called are used mostly on commercial applications and on automobile air conditioning installations. Double flares are stronger and usually cause less trouble if properly made. Fig. 2-10 illustrates how a flare is used to form a leakproof joint between a tube and a fitting.
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Fig. 2-9. Some practice bends on tubing. A-90 deg. bend on 1/4 in. tubing. B-360 deg. bend on 1/4 in. tubing. C-90 deg. bend on 1/2 in. tubing. D-180 deg. bend on 1/2 in. tubing. |
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Fig. 2-10. A cross section of a flared fitting. Note -that the seal is made by the flare nut surface press- ing the flare against the mating surface of the fitting. All of the mating surfaces are accurately machined. |