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.
1. Good Fit and Proper Clearance
Swage the tubing, as required, to obtain a good fit. It will be necessary to add tubing and/or form connecting tubing when installing a replacement compressor. The clearance between tubing should be a snug fit to prevent the alloy from flowing inside the tubing. All tubing connections are made by attaching the end of one tube to the end of another. This is easily done if one tube is one size larger than the other. The end of a ¼" O.D. tube will fit into the end of a ¾ 6" O.D. tube; ¾ 6" into %"; ¾" into ½" O.D., etc. If two tubes of the same size are to be joined, however, the end of one of them must be enlarged one size by a process called swaging.
The swaging tool is used in conjunction with a flare block. The tubing is clamped in the flare block so that its tip projects an amount equal to the distance between the tip of the pilot end and the start of the enlarged portion of the swaging tool. The tool is then slipped into the end of the tubing and tapped in with a hammer until the tip of the tubing has slipped up over the expanded section as far as it will go. The swaging inches, unless specified otherwise. CAUTION: Do not force capillary tube into drier screen.
Steel tubing cannot be swaged - it will split. One of the connecting tubings must be of copper, which can be swaged. If, however, a steel tube is out of round, it may be reshaped by inserting a swaging tool of the same size as the tube.
Sample Speed Swage Kit
Chapter 4 Page 9
Sample Hammer Type Swage
Sample Swage/Flare Kit Includes Tubing Cutter and Torch Wrench/Key
Hand Held Swedge