In any case, the mouthpieces of copper pipes must be deburred and lightly sanded with emery cloth, in order to ensure the perfect durability of the connection over the time.
The biconical fitting, or «olive» fitting, or even compression fitting, is a plumbing fitting without welding but which guarantees waterproof. It does not require any special tool but a pipe cutter and an adjustable wrench or universal pliers.
It is mainly used in fixing or renovation. Exclusively designed for copper pipes, this connection is composed of a central piece, nuts and a bicone ring, commonly called olive. The olive in question is crushed when the two nuts are tightened and thus ensures the connection is waterproof.
Warning: once positioned and tightened, the olive fitting will no longer be reusable and need to be totally changed.
These connections require the preparation of a collet, which is achieved by means of a pipe flaring tool. The device consists of a matrix with several standard diameters (marked), opening from the sides, and a bracket fitted with a spindle to flare at 60 ° in the case of a screw system, or a free spindle in the case of a simple beating system.
The end of the tube is heated (500 °), positioned in the die corresponding to its diameter, outcroping about 3 mm (the size of the collar) and spread by the router, screwing or knocking. Before any assembly operation, it is necessary to anticipate the positioning of the nuts and washers on the tube.
Tightness will be ensured by means of a rubber washer placed between the collar and the fitting. There are collar fittings where the waterproof is provided by the plasticity of the copper collar itself. They can be used for annealed or work hardened tubes. In the latter case, the part of the work-hardened tube providing the waterproof must always be annealed.
In plumbing, the flaring is the operation of widening the end of a copper tube so that another tube, also copper, of the same diameter can be inserted. In order to be assembled the copper tubes must be brazed. This type of assembly must made exclusively by fittings between copper tubes only.
With the torch, heat the copper tube where you want to make your connection, taking into account the height of the socket head. Then cool it by immersing it in cold water. Lock the tube in your vice, protecting it so as not to deform it, and insert the socket tool which will be struck until the bearing of the necessary diameter is reached (usually possible from 8 to 16 mm). To connect a tube of 8 to another tube of 8, you will need to make a socket of 10. This technique therefore requires neither welding nor sleeve.