and the appearance and quality of the weld are
SECURING OXYGAS WELDING EQUIP-
MENT.To extinguish the oxygas flame and to secure
equipment after completing a job, or to interrupt work
temporarily, take the following steps:
1. Close the MAPP-gas needle valve first, then
close the oxygen needle valve to extinguish the flame.
2. Close both the oxygen and the MAPP-gas
cylinder valves. Leave the oxygen and MAPP-gas
regulators open temporarily.
3. Open the MAPP-gas needle valve on the torch
and allow gas in the hose to escape (5-15 seconds) to the
outside atmosphere. Do not allow gas to escape into a
small or closed compartment. Close the MAPP-gas
4. Open the oxygen valve on the torch and allow
gas in the hose to escape (5-15 seconds). Close the
5. Close both oxygen and MAPP-gas cylinder
regulators by backing out the adjusting screws until
they are loose.
Follow the above procedures whenever your work
is interrupted for an indefinite period. When work is to
stop for only a few minutes, you do not have to secure
the cylinder valves nor drain the hose; however, for
any indefinite work stoppage, follow the entire
extinguishing and securing procedures. For overnight
work stoppage in areas other than the shop, it is safer to
remove the pressure regulators and the torch from the
system. Double-check the cylinder valves to make sure
they are closed securely.
Maintenance of Gas-Welding
Welding equipment must be kept up if it is to work
well for a long time. You do not have to make repairs to
welding equipment; but when repairs are needed, see
that the equipment is removed from service and turned
in for repair. You are responsible for various duties in
the maintenance and care of oxygas welding
equipment. This section identifies some of the
common types of maintenance duties that you can
expect to perform.
Ensure welding torches are kept away from oil and
grease. At times, the needle valve may fail to shut off
when hand-tightened in the usual manner. If so, do not
use a wrench to tighten the seat in the valve stem.
When foreign matter cannot be blown off the seat,
remove the stem assembly and wipe the seat clean
before reassembling. Be sure and keep the mixer seat
free of dust, dirt, and other foreign matter.
Before a new torch is used for the first time, check
the packing nut on the valves to make sure it is tight.
Some manufacturers ship torches with these nuts
Welding tips get rough treatment at times. So keep
the orifice smooth and clean if you want the tip to work
well. When cleaning a welding tip, do not enlarge or
scar it. Remove carbon deposits and slag regularly.
Avoid dropping a tip because the seat that seals the
joint may be damaged. The flame end of the tip may
receive mechanical damage if you let it contact the
welding work, the bench, or the firebricks. This
damage can roughen the end of the tip and cause the
flame to burn with a fishtail.
Special welding tip cleaners have been developed
to perform this service satisfactorily. The cleaner
consists of a series of broachlike wires that correspond
in diameter to the diameter of the tip orifices. These
wires are packaged in a holder that makes their use safe
and convenient. Some welders prefer to use a number
drill that is the size of the tip orifice to clean welding tip
orifices. A number drill must be used carefully, so the
orifice is not enlarged, bell-mouthed, reamed out of
round, or otherwise deformed.
The flame end of the tip must be clean and smooth.
Its surface must be at right angles to the center line of
the tip orifice for a flame that is shaped correctly. A 4-
inch mill file is used to recondition this surface.
Should the end of the torch tip become rough and
pitted and the orifice become bell-mouthed,
recondition the tip. Place a piece of emery cloth, grit
side up, on a flat surface; hold the tip perpendicular to
the emery cloth; then rub it back and forth just enough
to true the surface and to bring the orifice back to its
If there is leakage around the TORCH VALVE
STEM, tighten the packing nut, and repack it if
necessary. For repacking, make sure you use only
packing recommended by the manufacturer of the
torch. DO NOT USE ANY OIL. If the valve stem