Chapter 4 Page 8
Prest-0-Lite brazing equipment, or its Uniweld equivalent, is capable of making permanent leak-tight joints in refrigeration systems. The proper torch is essential to get adequate, controlled heat distribution. Since good joints depend on proper preparation before brazing, other necessary items are emery cloth, wire brush, file, and brush for flux.
There are two types of torch tips commonly used for good brazing technique: the "twister" tip (or turbo-torch) and the double tip torch. The wister 'tip may be used with either a single or a dual gauge regulator. One gauge indicates the amount of acetylene remaining in the tank. The second gauge registers the pressure of the acetylene leaving the regulator and entering the hose.
The twister tip through its design, uses a large amount of air. Spiral baffles or vanes in the torch tip cause the gas-air mixture to form a twisting, swirling flame as it leaves the torch. In order for it to work correctly, the pressure regulator must be set at its 15 psi capacity pressure. Less than this will cause the flame to burn down inside the torch tip and damage it. When brazing a tubing joint, the extremely hot flame will surround the tubing completely to give a proper alloy flow pattern.
The double tip torch has been popular for several years and may still be used if the "twister" tip is not available. It does not produce heat as fast and may allow oxidation to form before the alloy flows, particularly on larger tubing. The double tip compensates for its lower heat by applying heat to both sides of the tubing at the same time. The space between the two tips may be adjusted by bending them closer together or farther apart until the tips of the flame barely touch the metal.
The faster the heat can be applied, the faster the braze can be completed and the heat removed, and less oxides and scale will form inside the tubing. This is particularly true when the joint is close to the compressor or on large copper tubing which tends to draw heat away from the joint.
Acetylene is a gas that is utilized in brazing and is in a pressurized container. Use care in handling the tank or container. If the valve is broken off, the container can become a powerful rocket which can inflict harm to people as well as property. Be sure the tank is securely fastened whenever it is being transported as well as stored. Handle carefully on a job site, in the shop, or in a customer's home. Keep it in an upright position. Always secure tanks containing acetylene gas. Before igniting the brazing torch, check to make sure there are no leaks by using a bubble solution. When components of a refrigeration unit are replaced, it is necessary to reseal the joints to complete the repair. Good brazing habits are obtained through practice and experience. Five basic steps should be followed when brazing permanent leak-tight joints. A description of these five steps follows.
Turbo Torch - This torch got is name from the loud hard blowing flame. This type of torch uses only 1 tank "Acetylene" This torch is easier to use with less flame adjustment when lighting. This torch will braze Aluminum, Copper, and Steel. The flame temperature is approximately 2700 Degrees F
Oxy-Acetylene torch set - uses two tanks one Oxygen and the other Acetylene. The torch can produce up 6,000 Degrees F. This torch is the torch of choice in the the industry of Appliance and AC repair. The flame on this torch can be mauch considerably smaller than the turbo torch and much quieter. This makes it ideal for working in smaller spaces, but care needs to be taken as with the excess heat produced from this torch makes it easier to burn right through the tubing. The main drawback of this torchis you need to maintain 2 separate tanks and make sure both have sufficient fuel for the job before going and lighting the torch to get the best flame takes some getting used to each torch is different and hasits own learning curve.