1. Cut and clean the ends of the tubes as described earlier. Use a fine-toothed file to smooth the ends or to make a slight correction if the tubing is not cut perfectly square.
2. Place a female flare nut on each of the tubes with the larger end facing the cuts. (Do this prior to making the flare because the nut will not slide over the end after the flare is made.)
3. Slide the nuts back on the tubes to provide enough working room. Then put the end of the first tube into the flaring block hole with the same diameter as the tube. The end of the tube should extend slightly above the chamfered end of the hole to allow enough metal to form a satisfactory flare. The tools have directions with them for guidance in this step. As a rule of thumb, the extension above the block should be about one-third of the height of the flaring. (See fig. 25a and 26.)
4. Put a drop of refrigerant oil on the bottom of the flaring cone where it comes in contact with the tubing.
5. Tighten the spinner until the flare is formed. Avoid overtightening as this will thin out the wall of the tube and weaken the flare. In most cases, after the spinner touches the tubing, about six and a half turns should form the flare.
6. Do the same with the other piece of tubing that is to be joined. (Don’t forget to put the flare nut on first!)
7. Use Pipetite (a pipe-fitting compound) or a short length of Teflon tape around the male threads to establish an airtight seal. Teflon is the better of the two. If the compound is used, be sure to apply it sparingly to prevent it from getting into the lines when the flare nuts are connected.
(NOTE: Connections made in plastic tubing [such as a water supply to an ice maker] use compression-type fittings since plastic cannot be flared.)