When possible, first reduce the area of the hole by driving in softwood wedges. They are not to be driven in too far or
they will retard the flow of fluids. The wedges are then to be trimmed flush with the outside of the pipe, after which the
area is to be covered with a strip of sheet or rubber packing tightly held in place by two layers of marline or wire. The
packing must extend about 2 inches on either side of the hole.
The use of white lead or red lead paint on any fresh water pipe is prohibited, even in an
emergency, due to the potentially toxic hazard of addition of lead to water that may be used for
drinking. Personal injury could result.
The soft patch can be modified or improved to suit immediate conditions. Often it is advisable to have a curved plate of
lightweight sheet metal between the packing and binding. A coat of white or red lead on the face of the packing also
helps. Small solid rubber balls also can be used to patch holes in pipes. The ball is placed over the hole and secured by
banding, wiring, shoring, or wedging.
Marline and oakum have been used successfully as a caulking material in cracks. In many cases, as on sharp curves, it
is not possible to use sheet packing, but combinations of wedges, marline and various plastics will often make effective
d. Wooden plugs. Wooden plugs covered with cloth have stopped many jagged holes in piping. Sometimes,
combinations of plugs may be used. Set up on the plugs with a hammer and try to secure them in place with clamps or
wires. Otherwise they may work out under pressure. If the hole is not too large, it may be drilled and tapped for inserting
a screw plug.
e. Thumb clamps and C-clamps. C-clamps and thumb clamps may be used to hold plugs or patches in place. For
example, a block of soft wood may be rough-shaped to fit over a damaged area in a pipe, and the pad may be held in
place tightly with two thumb clamps. Care must be taken to reinspect patches held in place by clamps as they have a
tendency to work loose under shock or vibration.
f. Caulking with hammer and chisel. Light caulking with hammer and chisel has sometimes been used to close
small crack leaks, especially adjacent to flanges. There is always a danger of opening the crack even wider.
g. Welding and brazing. Welding, brazing, and silver soldering can be used to repair leaks, especially at the joint
between pipe and flanges. However, these methods are slow, are not reliable in the hands of unskilled personnel, and
may lead to fires and explosions. Therefore, their use in combat is limited.