achieve proper powder supply. Powder supply depends
used to ensure sealing of the seats; a wrench is not
upon base metal temperature. The powder may be
required for tightening.) The double O-ring seats must
applied and fused simultaneously or it may be sprayed
be properly seated for the torch to perform satisfactorily.
to the work surface and then fused (wetted-out).
The O-rings or seats should be replaced if they are
Whether you spray and fuse simultaneously or fuse after
damaged through wear or misuse. Next, thread on the
spraying, do not travel forward with the torch, leaving
tip assembly and tighten it wrenchtight. The tip should
unfused powder behind.
point downward for normal flat work. Remove the
closure from the bellows module, invert the torch, and
Once sufficient base metal temperature is reached,
insert the module into the connective junction at the top
you should usually make the balance of the deposit with
of the valve assembly. To do this, you will need to align
the torch lever in the fully depressed position. However,
the lugs on the module with the openings in the junction.
you may experiment with the position of the lever to
Next, seat the module by turning it 90° clockwise; take
ensure continuous operation. If necessary, you can
care that the connective junction on the torch is clean
adjust either the needle valves or the regulators to get
and free of all foreign matter.
better operating conditions. When making powdered
metal deposits, a slight weaving motion is generally
CAUTION: Do not turn the module beyond 90°,
your best technique. The exact area and shape of the
as improper seating may occur. Connect the torch body
surface where the deposit is being made will determine
to oxyacetylene hoses which have standard 1/4-inch
the extent of the weaving motion. To ensure proper
fusion at the end of the beads, shut off the powder supply
The gas pressures used with the powdered metal
by releasing the lever, and fill the final crater by using
torch will vary according to the size of tip being used.
previously deposited powder.
When using the larger tips, set the oxygen regulator
The actual distance between the torch tip and the
pressure from 25 to 30 psi and the acetylene regulator
work surface will vary depending upon the type of work
pressure from 4 to 5 psi. When using the small tip, set
and the operator of the torch. Usually, this distance will
the oxygen regulator pressure from 15 to 18 psi and the
vary from one-fourth to three-fourths inch. In some
acetylene regulator pressure from 2 to 3 psi. When all
joining applications, it may be best to hold the gap more
connections have been properly made and the
than three-fourths inch, depending upon joint design
appropriate gas pressures set, the powdered metal torch
and base metal thickness.
is ready for operation.
When you apply powdered metal to flat surfaces,
hold the tip vertical to the work, and keep the bellows
module as near perpendicular as possible. You can
The powdered metal torch is lit in the same manner
rotate the tip assembly a full 360° to help you apply
as an oxyacetylene torch. Open the acetylene valve and
powder in the vertical, horizontal, and overhead
ignite the gas. Then, open the oxygen valve and adjust
positions, and the module will still be maintained in a
the flame to suit the work. A neutral flame is generally
near perpendicular position. The thickness of the
best. In the event that you experience difficulty in
deposits will depend on any or all of these five factors:
maintaining the flame, adjust both the needle valves and
Size of tip
the regulators until the right combination is reached.
The smaller tip should be used for small flames.
Quantity of powder fed into the flame
(Cutting back the gases will choke the flame and cause
the tip to overheat.)
Speed of torch over work (slower speeds are used
for greater buildups)
After adjusting the flame for the alloy being used,
preheat the base metal, keeping the torch in constant
Temperature of base metal
motion. The method and amount of preheat are
Rate of (continuous or intermittent) power fed
determined by the type of work. When color begins to
into the flame
show in the base metal, concentrate the flame at the
starting area until a dull red color (for steels) is reached.
At this point, slowly depress the lever and observe the
POWDERED METAL APPLICATION
passage of powder through the flame.
The torch is best operated with the lever fully
When you apply powdered metals, preparation of
depressed, but you should experiment with the lever to
the base metal is very important. The surface to be