Tables, stands and special supports are provided
for holding the work while being welded, and in order to handle the various
metals and allow for their peculiarities while heated use is made of ovens
and torches for preheating. The operator requires the protection of
goggles, masks, gloves and appliances which prevent undue radiation of the
heat.
_Torch Practice._--The actual work of welding and cutting requires
preliminary preparation in the form of heat treatment for the metals,
including preheating, annealing and tempering. The surfaces to be joined
must be properly prepared for the flame, and the operation of the torches
for best results requires careful and correct regulation of the gases and
the flame produced.
Finally, the different metals that are to be welded require special
treatment for each one, depending on the physical and chemical
characteristics of the material.
It will thus be seen that the apparently simple operations of welding and
cutting require special materials, instruments and preparation on the part
of the operator and it is a proved fact that failures, which have been
attributed to the method, are really due to lack of these necessary
qualifications.
OXYGEN
Oxygen, the gas which supports the rapid combustion of the acetylene in the
torch flame, is one of the elements of the air. It is the cause and the
active agent of all combustion that takes place in the atmosphere.
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