Scaling is done by using either tool shown in figure
18-2. A chisel is used with the pneumatic hammer and
must be held so that the chisel strikes the surface at
approximately a 45º angle. As with the hand scaling
hammer, take care that you don’t dent the surface. The
rotary scaling and chipping tool shown in figure 18-2
(called a deck crawler) has a bundle of cutters or
chippers mounted on either side. As it is pushed along
the surface to be scaled, the rotating cutters do the work.
This tool is particularly helpful on large deck areas.
The electric disk sander is another useful tool for
preparing surfaces. However, it must be used with care.
If too much pressure is applied or it is allowed to rest in
one place too long, it will quickly cut into the surface,
particularly wood and aluminum surfaces.
POWER TOOL SAFETY PRECAUTIONS.—
You must be trained and qualified before you operate
portable power tools. You must observe the following
safety precautions when working with electrical and
pneumatic (air) tools:
Wear eye and ear protection while chipping,
grinding, sanding, or wire brushing. If dust is
excessive, also wear a respirator. Do not wear
jewelry or loose fitting clothing.
Do not use defective tools. If you have any doubt
about the condition of any tool, show it to your
supervisor, who will have its condition
determined.
Make certain that electrical power tools are
grounded properly. Every portable electrical
power tool must be provided with a ground lead
that connects the tool casing to the ship’s
structure and an up-to-date electrical safety tag.
Give your full attention to your job.
Give electricity the respect it is due—115 volts
can and does kill.
Do not operate power tools in areas where
flammable vapors, gases, liquids, or exposed
explosives are present.
Do not allow power cords and air hoses to kink or
come in contact with oil, grease, hot surfaces, or
sharp objects.
Do not lay power cords and air hoses over
ladders, steps, scaffolds, or walkways in such a
manner as to cause a trip hazard.
Do not use compressed air to clean clothing
being worn or to blow dust off the body.
PAINT
Paint consists of four essential ingredients:
Pigment
Vehicle (known as the base)
Drier
Thinner
Pigment provides the coloring, rust prevention (in
primers), and the lasting quality of the paint. The most
common pigments are made of metals, such as lead,
zinc, or titanium.
18-12
Student Notes
:
Figure 18-1.—Portable grinder and wire brush.
Figure 18-2.—Power scaling tools.
