The process used to soften copper is called
annealing. The word anneal means to soften
thoroughly and render less brittle. Copper is unlike
steel in many respects. If copper is bent often, it could
break when you try to bend it again. Should the
pressure on a copper tube increase or decrease too
much, the tube could break. Vibration also makes
copper tubing break.
To soften steel, heat it to a cherry red and cool it
very slowly. The slower it is cooled, the softer the steel
becomes. With copper, the opposite is true. Copper is
heated uniformly to a dull red and then quenched
(dipped) in water (for water service). The faster it is
cooled, the softer the copper becomes.
BENDING.Copper, properly annealed, can be
bent by hand when sharp bends are not desired. Copper
partially collapses during the bending process if a
tubing bender is not used or if the copper is not filled
with some kind of easily removable material, such as
sand. Simple bends can also be made by wrapping the
outside of the copper tightly with soft wire and bending
the copper by hand; however, if a line must make a 45-
or 90-degree bend, you should use a tubing bender.
Hand-tubing benders are available for each size of
copper. These benders assist you in making neat,
accurate bends easily, quickly, and without marring
the copper or restricting the flow through the copper. It
is easy to make a bend but difficult to get the bend in
the correct location on the copper and to the correct
degree. Be certain that you have the correct size bender
for the copper you intend to bend. A bender that is
either too small or too large for the copper will make a
faulty bend. Figure 3-40 shows one type of tubing
bender. Figure 3-41 shows a typical one-story copper
Figure 3-40.Portable copper pipe and tubing bender.
MEASURING.Seven methods are used in
measuring pipe or tubing. They are (1) end to end, (2)
center to center, (3) end to center, (4) end to back, (5)
center to back, (6) back to back, and (7) face to face.
These measurements are also used in measuring
threaded galvanized or black iron pipe.
The measurements are generally made with a
ruler. Each of the seven methods mentioned above is
explained below, and each one is shown in figure 3-42.
END TO END indicates a pipe threaded on both
ends. The measurement is from one end of the pipe to
the other end, including both threads.
CENTER TO CENTER means there is a fitting on
each end of the pipe. The measurement is made from
the center of the fitting on one end to the center of the
fitting on the other end.
END TO CENTER method applies to pipe having
a fitting on one end. The measurement is made from
the end of the pipe to the center of the fitting.
END TO BACK also refers to pipe with a fitting on
one end. The measurement is from the back of the
fitting to the other end of the pipe.
CENTER TO BACK indicates a pipe with a fitting
on each end. The measurement is taken from the center
of one fitting to the back of the other fitting.
BACK TO BACK measurement refers to pipe with
a fitting on each end. Here the measurement is from the
back of one fitting to the back of the other fitting.
FACE TO FACE measurement refers to a pipe
with a fitting on each end that has an opening directly
across from the pipe it is connected to on both ends.
Measure from the face of the opening to the face of the
CUTTING AND REAMING.Copper should
be cut with a tubing cutter, when available. Mark the
copper where it is to be cut and install the cutter so the
cutter wheel is over the mark, and you can see the
cutting wheel from the top view of the pipe, as shown
in figure 3-43. Now turn the adjustment wheel or
handle clockwise to force the cutter wheel against the
copper. Continue revolving the cutter, turning the
adjustment wheel slightly after each revolution until
the copper is cut through and it separates.
Copper may be cut with a hacksaw, although a
tubing cutter is preferable; however, be careful to cut
the copper square if it is to be flared. Be sure to use a
fine-toothed hacksaw blade, 32 teeth per inch, when