Service manual

STP 11-25R13-SM-TG
A - 7
c. Solder fillet
is a smooth concave buildup of solder between connected metal surfaces.
d. Wicking
is a condition in which the capillary action of a metallic surface causes the flow of
molten solder.
e. Wetting
is a condition in which molten solder properly flows, covers, and bonds to metal
surfaces.
f. Tinning
is coating metal surfaces with a uniform layer of solder.
A-9. Preparation of Wires.
Prior to soldering a wire to any terminal, the wire must be prepared. First the wire must be stripped
and then tinned. The procedures for stripping and tinning a wire are listed here.
a. Stripping
. Remove insulation from wires using an approved stripper. Determine the length of
stripped wire by the type of terminal, whether maximum or minimum wrap is used, and the required
amount of insulation clearance. Insulation clearance is the length of exposed bare wire between the
insulation and the terminal after the connection is complete. Minimum insulation clearance shall be one-
wire diameter (including insulation) and maximum clearance shall be two times that amount. The desired
insulation clearance is one-wire diameter (including insulation).
b. Checking
. When insulation is removed using a precision cutting-type stripper, check the cutter
to ensure that the correct stripping hole is used for the corresponding wire size. During the stripping
operation, twist the stranded wire in the direction of the lay in order to maintain the original form and
prevent separation of the individual strands.
c. Examination. After stripping, examine the wire for insulation damage. Do not use wires with
cut, split, or burned insulation. However, slight discoloration from thermal stripping is acceptable.
Examine wire strands for stretching, nicks, cuts, scrapes, or other damage that degrades connection
reliability. Figure A-12 shows acceptable and unacceptable wire conditions after stripping.