d. Adjusting the flame. The flame adjustment for the gasoline blowtorch is
made by turning the flame adjuster valve wheel - counterclockwise to open the valve
and clockwise to close it. Opening the valve produces a longer and hotter flame,
while closing the valve produces a shorter and less intense flame. When the torch
is used for heating the soldering iron, adjustment of the flame will depend upon
the size of the iron to be heated. When the torch is used as the soldering tool,
the flame adjustment to obtain proper heat will depend upon the size of the area to
be soldered.
e. Extinguishing the flame. To extinguish the flame of a blowtorch, the
needle valve should be closed gently - never too tight, as this will enlarge the
precision orifice and damage the delicate valve seat. When the torch is hot, the
valve seat is in an expanded state and the needle (if closed tightly) would be
turned into the orifice too far, causing it to jam and stick when the torch cools
and the metal contracts. As a precautionary measure, the needle valve should
always be backed out slightly after the flame is extinguished, but not enough to
allow any fuel to escape.
Note.
-
It is well to make a safety check after the torch has cooled, to
determine if gasoline is seeping or dripping from the blowtorch burner.
f. Maintenance. The most frequent cause for malfunctions of the blowtorch is
that of carbon deposits forming in the small fuel passage. These deposits may be
removed by unscrewing the cleanout plugs and hand twisting a small drill of exact
size into the passage. When a drill of the proper size is not available, a short
length of stiff wire may be used.
Note.
-
One cleanout plug is in the top of the generating unit behind the
soldering iron hook, the other below the needle valve (fig 23).
CAUTION:
It is important to choose a drill of the proper size since a drill too
large will cut out and enlarge part of the passageway and a drill too
small will not remove all the carbon deposits.
33. OXYACETYLENE EQUIPMENT. The oxygen-acetylene torch and apparatus used for
soldering is the same as that used for welding and brazing which has been covered
in sections III and V of this lesson. The flame used for soldering is the reducing
or carburizing flame.
34.
SOLDERING PRINCIPLES.
a. Introduction. Soldering with externally heated or electric soldering
irons may be quite simple, providing the following factors are remembered:
(1) The correct size and shape of iron must be selected for the particular
work to be done, and the tip should be tinned properly.
(2) Solder will not stick to dirty, tarnished, or corroded metals.
(3) The correct type of flux and solder should be used.
(4) The soldering iron must not be overheated.
(5) The area to which the solder is to be applied must be hot enough-to
melt the solder, or poor adhesion will result.
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