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TM 9-254
4-13.
Soldering Techniques - Continued
(8)
When the temperature of the sleeve bushing (3) and the bellows (5) rises to a point that will cause the
solder to melt and flow into the joint, discontinue heating with the torch and apply solder (2) to form an
even-continuous fillet around the sleeve bushing and the bellows.
NOTE
Heat applied to the bellows during the soldering operation will cause the bellows to change
physical length.
(9)
After the solder joints have cooled, measure the distance from the shouldered shaft (1) at the threaded
end, to the sleeve bushing (3). The distance measured (A) must be between 0.468 and 0.500 inches.
CAUTION
Do not score the sleeve bushing when using pliers to make adjustments to the bellows.
(10) If the measurement taken in step (10) is not within tolerance, reheat the bellows (5), do not apply heat to
the solder joints. Grip the sleeve bushing (3) with a pair of pliers and either compress or stretch out the
bellows.
(11) Measure the distance (A) again and if necessary repeat step (10) above.
(12) Allow the bellows assembly to cool completely and then remove all flux residue from the solder joints
with a medium stiff bristle brush dipped in alcohol.
4-14.
Desoldering Techniques.
Solder may be removed from conductors and terminals by mechanical vacuum devices, wicking with a stranded
conductor, or shielding braid and flux. The stranded conductor or shielding braid method will be discussed in this section.
(1)
A well-tinned soldering iron tip shall be used to melt solder connections when conductor wires are
removed from component terminals.
(2)
To remove conductors from solder joints, preclean joint to be desoldered with a noncorrosive solvent
such as alcohol.
(3)
Choose a size of stranded wire or shielding braid that is large enough to do the job properly but not too
large. The larger the stranded wire or shielding braid, the more heat required to desolder the joint and a
greater possibility of damaging the circuit.
(4)
Dip approximately 1/2 inch of the stranded wire or shielding braid into liquid flux or use a commercially
available desoldering wick that already contains the flux (app B). Shake off any excess.
Change 4 4-35
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