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Greetings,
Regarding the recent discussion of solder connections vs. crimped
connectors, we ought to look at the physics. The claim is often heard that
a soldered joint is rigid and that vibration flexes the wire back and forth and
work hardens the copper at the point where it becomes rigid, which will then
make the wire break at that point.
But think about a crimped connector. Where the wires enter the metal
barrel, the individual strands are squished into basically a single piece
of copper, as rigidly as if they were soldered. (A crimped connector has
to squeeze the strands so tight that it makes the joint air tight.) The
AMP PIDG connectors add a second barrel to crimp the insulation to reduce this
risk, but it seems to me that there is still a transition point where the
flexible, stranded, wires become essentially a single, solid wire.
So both soldered joints and crimped ones have exactly the same
physics: in both cases, flexible multi-strand wires are turned into a
single, rigid piece of copper. As someone has already said here, the key
is to support the wire near the connector to minimize vibration-induced
flexing. Good advice.
I believe soldered connections aren't used in factories any more because
soldering requires more skill than crimping. An aircraft factory uses
calibrated crimpers that are relatively insensitive to operator
variability. I use both soldered connections and crimped ones, depending
on whichever seems more convenient for that particular connection. For
crimped connections, I use low cost ratchet crimpers and high quality AMP PIDG
connectors. Harbor Freight sells a crimper that works great;
B&C and SteinAir also sell great ones at affordable prices. For
soldered connections, I use a fancy soldering iron I bought on EBay, but
just about any soldering iron will work if you spend the time to learn how to
use it.
Dennis Johnson
Legacy #257, connecting millions of tiny instrument panel wires to millions
of tiny airframe wires; hoping for first flight in February.
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