There is a MIL and ANSI spec procedure for soldering wires for this
purpose. It calls for the following steps ( if memory serves me
correctly ):
1. thoroughly clean the wire with a fiberglass contact cleaning brush (
any electronic supplier ). This removes any oxidization.
2. clean the wire with denatured alcohol. This removes any other
contaminants.
3. clamp the wire with a special heat sink clip at the edge of the
insulation. This prevents the solder from wicking under the insulation.
4. apply liquid flux to the wire ( most flux core solder doesn't contain
enough flux to do high quality work and it is frequently dried up in the
solder from sitting to long before being used )
5. tin your soldering iron and shock it clean by wiping it on a wet
sponge
6. apply heat to the wire with the iron
7. apply solder to the opposite side of the wire to the iron never
directly on the iron, apply just enough solder to flow through the wire
but not so much that you can't still see the individual strands of wire.
8. clean all the flux off the wire after it has cooled with denatured
alcohol
Some additional notes:
- always cut the end of the wire to be tinned so it is just long enough
to go in the connector flush to the edge of the insulation and do this
BEFORE TINNING not after.
- always leave enough wire so there is a strain relief loop
- always support your wiring harness with cable clamps don't leave it
hanging by the terminals
- if the wire is going to be in a high vibration environment ( most
connections on your LBC ) such as a coil wire, a small piece of shrink
wrap should go over the end of the terminal and be long enough to reduce
the strain on the solder joint about 2-3 times the length of the
shoulder of the terminal.
- when installing ring or spade terminals always tin both the terminal
and the wire before joining them together follow the above steps 1-8 for
both parts and repeat them before joining the wire and the terminal.
- every solder joint should be shiny as a new dime when finished if not
it is dry or cold redo it !!!
If you follow these guidelines you should be able to make very reliable
solder joints that will tolerate even a ride in the space shuttle.
Doug Hamilton
17 years of repairing military and scientific equipment
2 week course on mil spec repair of circuit boards ( 3 days would have
covered it !!)
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