(c) Apply a thin coat of noncorroding flux to the polished portion of
both the tubing and the fitting.
(d) Push the tubing into the fitting and turn it a few times to spread
the flux evenly. Remove excess flux from the outside of the fitting.
(e) Heat the connection evenly with a torch; apply the flame directly to
the fitting. On large size tubing (over 1-1/4 inches) use two torches, when
possible, one on each side, to obtain even heating.
(f) When the flux bubbles out (about 45 seconds with an acetylene torch
and about 1 minute with a liquified-petroleum torch), remove the torch and apply
the end of a length of wire solder to the edge of the joint. If the fitting and
tubing are hot enough, the solder will melt and be drawn into the joint. When a
line of solder shows completely around the joint, the connection is filled with
(g) Take the following precautions when making soldered connections:
1. When the joint is close to wood or other combustible material,
place an asbestos or metal sheet between the fitting and the combustible material.
2. Make sure that the tubing and fitting are kept motionless while
the solder is cooling. Any movement may-result in a faulty joint. Solder will
harden in a minute or less if the joint has not been overheated.
3. When tubing is joined to a fitting that is already soldered to
other tubing (as in joining to the side takeoff of a tee already joined to a
through line), wrap a wet rag around the finished joints. This prevents the solder
in these joints from melting.
(h) Additional information on soldering is available in lesson 3.
a. Pipes. Small leaks in a system may require temporary or emergency repairs
if materials needed to repair them permanently are not readily available. A
permanent repair should be made as soon as possible to replace the weak or
defective part with units the same size and quality as the original installation.
Before making any repairs, relieve the pressure from the system. Pipes can be
temporarily repaired in a number of ways.
(1) Rubber hose or plastic tubing. Cut the pipe on either side of the leak
with a hacksaw or pipe cutter. Remove the damaged pipe section and replace it with
a length of rubber hose or plastic tubing by slipping the ends over the pipe and
fastening them with hose clamps. The inside diameter of the hose must fit the
outside diameter of the pipe.
(2) Sheet rubber. Wrap the leaking area with sheet rubber. Place two sheet
metal clamps, one on each side of the pipe, and fasten the clamps with nuts and
(3) Electrician's friction tape. Wrap several layers of electrician's
friction tape around the hole or crack extending it about 2 inches above and below
(4) Wood plugs. Small holes are sometimes filled with wood plugs. The plug
is driven into the hole after it is drilled or reamed. Hardwood is the best. The
plug will swell because it absorbs water and this prevents it from being blown out