MOTOR TRUCK SERVICE MANUAL
BODIES AND CABS
Manual, IR-50, should be reviewed and the safety
periodically to assure familiarity with the features of the
precautions covered therein observed. The instructions
MIG welder. Good practice would be to make trial. welds
provided with the MIG equip-ment (SE-2165) should also
on scrap aluminum before starting the work.
be studied to as-sure the proper operation and care of
this type of welder.
10. Keep the SE-2165 welder in good, clean operating
The welding of aluminum requires a few
11. All IHC vehicles using aluminum in the cab or body
additional precautions to be observed as follows:
structure have been designed and engineered to
1. First and foremost in the list of instructions in welding
provide the best possible service life. Do not make
aluminum is the need for cleanliness. The surfaces
changes in the structure design unless the changes
to be welded must be clean or the weld will be
have been approved as acceptable.
unsound and otherwise unsatisfactory. Both sides of
the work must be clean.
PROPERTIES OF ALUMINUM
2. Wear safety goggles under the welding helmet or
Lens shade #8 is considered
The following information will be of value in order to
satisfactory when 75 amp settings are used. Lens
clarify some of the peculiarities of which to be aware
shade #10 is best suited to 75-100 amp settings.
when welding aluminum:
3. Open containers of chlorinated solvents such as
1. Pure aluminum melts at 12200F.
carbon tetrachloride should not be left anywhere
aluminum alloys generally start to melt at 1050°F.
near the welding area. Ultra-violet rays from the
2. There is no color change in aluminum during
welding arc can cause the formation of toxic gas
heating. Weld temperature is indicated when the
when they come in contact with chlorinated solvents.
aluminum develops a glossy appearance.
4. Make certain that you are properly protected before
3. Aluminum conducts heat three times faster than iron.
starting to weld. Leather gloves, aprons and caps
4. Aluminum welds decrease (shrink) about six percent
are considered the best possible protection from
in volume when solidifying from the molten state.
weld splatter, sparks or other exposure to welding
5. Thermal expansion of aluminum is approximately
twice that of steel.
5. Ventilation is important in the welding area; however,
6. Speed of welding aluminum is an important factor in
excessive drafts or blasts of air should be avoided
preventing distortion due to heating.
when using the inert-gas welding equipment. The
7. Aluminum alloys loose characteristics of increased
flow of argon gas around the welding nozzle must
hardness and strength when re-heated to high
not be disturbed by air blasts, otherwise the effects
temperatures. Welding causes some annealing of
of shielding the work will be lost.
the parent metal.
6. Use grinding or sanding discs sparingly.
8. In MIG welding, preheating of the weld area is not
These high speed tools can quickly cut through the
required regardless of material thickness.
aluminum sheeting. Do not use files which would
9. Aluminum rapidly develops air oxide film upon
leave minute surface notches where cracks can
exposure to air. This oxide has a melting point
above the melting point of pure aluminum. (This is
7. Do not weld closed containers or fuel tanks.
one of the import-ant reasons for cleaning before
Welding on containers which previously have held
flammable materials is extremely dangerous.
10. The cleaning of aluminum surfaces before welding is
8. Do not weld around wet surfaces or on wet floors.
of major importance. Cleanliness cannot be over-
Make certain that ground circuits are securely
attached. Ground connections at the work should be
attached to the heavier sections of the aluminum
structure not on the cab skin or other thin sections.
9. Review the welding machine instructions