
Strike a Solder Joint Behind Enemy Lines - fogus
https://hackaday.com/2020/06/19/strike-a-solder-joint-behind-enemy-lines/
======
doodlebugging
I've used a similar technique I learned in the oilfield.

To solder a splice - 1) strip both conductors to be soldered about 1/2" and
form a loop on one. 2) Stick the second conductor through the loop formed in
the first and bend a loop around to join the wires. 3) Cut or break about 1/2"
of solder/flux and lay on something flat, clean, and hard - 2 out of 3 is good
enough here. 4) Use a hammer, flat rock, end of pocketknife, etc to flatten
the solder until it is about 1/8" wide and maybe twice as long. 5) Wrap the
flattened solder around the loops so that the join is covered by solder. 6)
Strike a match, use a lighter, a torch, etc to melt the solder and flux into
the joint. 7) Cover with weather-tight electrical tape and go on about your
business.

It never failed for me.

~~~
Animats
Here's the US Army field wire splicing technique, pre-WWII.[1] No soldering at
all, just tie the two wires together with a square knot, put a single copper
strand through the middle of the knot, and wrap the strand around the wire on
both sides of the knot for better conductivity. Then tape. When splicing a
pair, the wires are spliced with the splices staggered about 6" apart.

[1] [https://youtu.be/XGO9dboctkc](https://youtu.be/XGO9dboctkc)

~~~
magicalhippo
Watching old training videos like this and documentaries[1], it's striking
just how much better they are at conveying information.

They take their time. Shots linger, no jump cuts. No-one is driving around
while talking, interspersed with random unrelated scenery shots. There are
periods of silence.

At least on TV, most documentary style shows try to be so flashy and "cool",
with lots of unrelated content that serves no purpose except to make it harder
to think about what is being conveyed.

[1]: [https://vimeo.com/11932120](https://vimeo.com/11932120)

~~~
enriquto
The difference lies on the purpose of the videos. Sometimes you want to convey
a message, sometimes you want to sell ads. Each type of video is optimized for
its intended use case.

~~~
magicalhippo
But Horizon, made by the BBC, suffers from the same symptoms these days. BBC
has no ads to push. So I dunno. I hate it though.

------
flobosg
This is similar to solder seal wire connectors:
[https://www.youtube.com/watch?v=pGKsXSiFww4](https://www.youtube.com/watch?v=pGKsXSiFww4)

~~~
redis_mlc
Great link.

You know, that would be a great way to fix most intermittent headphone
problems, where you mainly need a strong mechanical result as much as the
electrical connection.

------
pugworthy
I can't be the only person who read this as, "Strike a Soldier Behind Enemy
Lines"

~~~
jakear
My initial parse made me think it was something about a particular type of
weed-cigarette soldiers used behind enemy lines.

------
nickcw
When I was at school I was in the combined cadet force, and being interested
in electronics I gravitated to Signals as it was known.

On exercises it was our job to provide communications and quite often we would
lay miles of copper wires in the woods for the field telephones and join the
wires together with these devices.

The black powder is some kind of thermite I think - lighting it would melt the
solder in the copper tube, you'd push the copper wires you'd pre stripped into
it and you'd hold it long enough for it to solidify, which was sometimes long
enough to burn your fingers!

In the UK in the 80s the CCF had lots of surplus WW2 equipment. Beautiful
valve radios and classic 303 rifles!

~~~
4gotunameagain
Thermite burns at around 2500 °C, copper melts at 1085 °C. Solder melts at
around 190 °C, and gunpowder burns at around 130 °C.

I believe that it quite improbable that it was thermite, probably gunpowder
with some additives (maybe a pinch of magnesium?)

~~~
analog31
Afaik there's a variation on termite that produced molten copper instead of
iron. Don't remember the chemistry.

~~~
Gibbon1
Still used for bonding ground rods in high power systems.

[https://www.youtube.com/watch?v=bBnbB3fiux0](https://www.youtube.com/watch?v=bBnbB3fiux0)

------
jasonjayr
Reminds me of rail road thermite welding:

[https://www.youtube.com/watch?v=5uxsFglz2ig](https://www.youtube.com/watch?v=5uxsFglz2ig)

------
metrokoi
What would actual use case for this look like? The post mentions
communication, but the usefulness of laying communication lines behind enemy
lines seems like it would be minimal. Lines would be easily discovered and
would lead right back to the spy or scout. The other use could be for
demolition which I could see, but if I were a saboteur I would just twist the
lines together as it's very temporary and time is of the essence.

~~~
sandworm101
Scout positions have hidden antennas. Demolition charges. Also probably useful
in cold/windy areas where dexterity is hard.

~~~
metrokoi
>Also probably useful in cold/windy areas where dexterity is hard.

Excellent point, hadn't thought of that.

------
praptak
There's a similar technique used in plumbing when you need to solder together
two pipes.

There's a pre-made fitting (H cross section) which has solder rings inside.
You press the pipes in and heat it until the solder comes out on both ends.

The technique needs an external source of heat but that's not generally a
problem in civilian plumbing.

------
bigdict
I can smell it from here.

------
zem
that sounds like it should be a cryptic crossword clue (:

------
ip26
Now that's a type of fusible link I'd never seen before.

------
ddrt
Is this a rap lyric somehow?

