you could also drill a hole through the pcb, and route your wire through
the hole before soldering it to the pad. Then the strain is on the wire
and not the solder joint. or route it through two holes. or one hole,
but a knot of wire on either side of the hole.
I've seen sealant/glue used before in devices i take apart so I'm sure
that works too
Since silicone sealant requires a setting and curing time (and contain
acetic acid, formaldehyde, and other icky stuff) why not get one of
those cheap $1 glue guns and some glue sticks. These heat up in a
minute, and the glue sets in 30 seconds. The "glue" is not really glue,
but a thermoplastic. But test first to make sure the glue has no
electrical conductivity. Most don't, but obviously the stuff with
glitter mixed in is not for PCBs!
Obviously you don't want to use this near components that will get
really warm, like a power transistor.
You may also find it helpful that if there is more than one wire from
the PCB to bunch them all together, and tie them with a tie-wrap. That
way all the wires act as their own strain relief. Sort of share the
strain thing. And as Andrew notes, if there's a free hole in the PCB, or
you can drill one without wrecking it, that's a good choice, too.
Generally, it's better to use header pins for connections rather than
soldering directly to the board, if there's any wire motion expected.
You can use stranded wire into a header connector. (If you're
using solid wire and are having wire break problems, going
stranded is the first step.) Header connectors with crimp pins
or insulation displacement connectors are what's generally used
to solve this problem.
Good advice. Another advantage of a header over solder is that it
is easier to disconnect and reconnect. That can be important on an
Another option is to use an FFC (flat flexible cable) or some other
cable/connector combination that is specifically designed for a
high vibration/shock environment. I have used FFCs with locking
headers for board interconnects in several designs and have
never had a connection fail.
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