Flaring
Mechanical joint is sometimes required or preferred to join copper or steel tubes together, instead of brazing, soldering, or welding. If you join tubes with a mechanical connection you need flaring. Flaring is used to make gas-tight or liquid-tight connection, and this process means forming the end of a tube.
Single flaring is the most used and the simplest process of flaring Both 37 and 45-degree single flares options are available. Rotary or spinning the flared end, and a ram forming are two available ways to accomplish single flared tube end.
If the tube ends are subjected to stress and fatigue the Double-lap flaring will offer additional strength. The joint is designed so that the inside surface of the flare has a larger diameter so it does not interfere with flow characteristics of the system. To meet the same specifications as the Single Flare, Double-lap flaring can be formed in the same shapes.
Different sizes of tubes require specific sets of equipment, but most flaring kits are easy to find and relatively inexpensive. To cut a tube the special cutting tool is used. A common flaring tool kit has two main parts – a flare form and a reamer. A flare form is like a clamp with a number of holes used for various tube diameters. The tubing is firmly held by the flare form, allowing you to flare the pipe using minimum strength A reamer has a conical point, a screw, and holding arms and makes the actual flaring.
The most common flare tube ends and corresponding flare fitting standards in use today are the 45-degree SAE style, and the 37-degree AN style, also used with the JIC system. The AN/JIC style generally has a higher pressure rating for a given size tubing. SAE and AN/JIC connections are completely incompatible due to the different flare angle. The hydraulic hoses are usually 37-1/2° flare connections, and the refrigeration and air conditioning industry usually uses 45° flare connections. According to NFPA 54/ANSI. Z223.1 National Fuel Gas Code, copper tubes used for natural gas, Liquefied Petroleum, or propane may use flared brass fittings of single 45°-flare type Nevertheless, all National Model Codes permit the use of flare fitting joints, the one should be consulted by the authority having jurisdiction (AHJ) to determine acceptance for a specific application
