>The latest issue of Sport Aviation has an article
>on wire termination. He recommends crimp and solder.
>The crimp for mechanical, and solder for the electrical.
For the life of me, I cannot understand why
folks recommend this practice. The companies
that make solderless devices and take the time
to get them Mil-Spec'ed and/or certified would
be equally confused. There have been hundreds of
thousands of airplanes and bizillions of cars
built with nary a solder joint in the electrical
system and they hang together just fine.
IF one is using poor tools then solder might be
useful, but if you're going to solder, why not
forget the crimp tools and solder everything?
Save some $.
>I thought solder caused a point of possible fatigue,
>and was not the best way to go.
Both crimp AND solder have ways of putting
stress risers into a group of wire strands
making them more likely to fail right at the
connection than anywhere else along the wire.
This is why crimp terminals have TWO places
to grab the wire . . . the ELECTRICAL joint
where the stranding is mashed into a homogenous
mass and the INSULATION GRIP where the wire
is supported to keep vibration stresses off
the electrical joint.
Soldered joints need heat shrink over the
joint for impoved support of the final
assembly.
In terms of overall reliablity, there is NO
difference between a properly soldered joint
and a crimped joint. The crimped joints are
prefered in a factory environment 'cause crimp
tools don't burn holes in the carpet and they
require less craftsmanship to operate than
a soldering iron. The folk who tout one over
the other or recommend BOTH as some sort of
reliability enhancement simply don't understand
the physics of the matter.
>Good quality terminals are a must. I use only "AMP"
>brand on the airframe. There are probably others out
>there that are good quality also, but I listened to
>my radio shop, and I haven't had any problems yet
>with my wiring, just the certified equipment connected.
Another myth propogated by folk who simply
don't take the time to understand the products
they use or recommend. AMP makes a full range
of terminals from open barrel, uninsulated
el-cheapos up through Plasti-Grip (automotive/
hardware store stuff) and topped off with the
pre-insulated diamond grip (PIDG) terminals
which have been standards of comparison for
decades. Dozens of other terminal manufacturers
make similarly scaled products in order to satisfy
the needs of a very large market. You can buy
terminals UN-SUITED for use in airplanes from
AMP or anybody else.
Bad or poorly supported advice is no substitute
for an understanding of how things work and why
we choose to use them.
Bob . . .
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