Check Out These Self-Soldering Sleeves from World War II
hackaday.com
hackaday.com
I was in the signals division of our school CCF (less drill and more playing with radios!) and it was our job to lay communications lines on field day. I have vivid memories of laying (what seemed like) miles of field telephone wires over heathlands and through woods and soldering them together with these self soldering sleeves.
They had a part on them like a match head which you could strike to set them off. They would get very hot and melt the solder inside the copper tube allowing you to push the two bared ends of wire in which hopefully you'd manage before burning yourself or the solder solidified again! I think they were something like thermite - they certainly smelt like it.
The CCF had lots of WWII surplus stuff, like massive radios with valves in and really leaky canvas tents!
What now seems completely surreal is that we also had all sorts of weaponry: rifles, Sten and Sterling sub-machine guns, Bren guns and even a couple of mortars. These were locked away in gun safes and anything automatic was supposed to be disabled, but anyone could have got in using an angle grinder and I'm sure that many of the guns could have been activated again. A more innocent age, I suppose.
I chose RAF over Army or Navy, thinking I'd get to fly at some point. Nope, just a co-flight in a glider once a year. Lame.
The army kids got to go to action camps, do paintballing, and regularly go to firing ranges. Again, all kids (~14yrs old) in the UK, in the middle of a London offshoot town with the rifles locked behind a rickety door.
For maybe 30 minutes, and lots of waiting around, but was fun. Got to do a fair bit of aerobatics as well. Obviously we weren't flying solo (although there were a handful that did a course that culminated in a solo flight)
Also went gliding once.
Just strip an identical length of insulation from the wires to be joined then form a U in each by bending them halfway thru the stripped section. Join the bent ends and give them a twist for a mechanical connection as you would in forming a Western Union twisted splice. You should put a heat shrink sleeve on one wire if you have one with you.
Take your ordinary solid core solder strip about 3X longer than your splice and use a hammer, the side of some pliers, a rock, etc to pound it flat so that it is then enough to bend easily.
Wrap the splice with this thin strip of solder across the whole splice and trim so that it doesn't overlap the insulated ends. Take a strike-anywhere match, a camper's match, a small butane torch, cigarette lighter, etc and hold it close to the solder until it melts into the splice. Then pull the heat shrink tubing over the splice if you have it and shrink it with your heat source. If you have no heat shrink tubing coat it with some 3M waterproof sealant, some rubber tape insulation, or plain electrical tape if that is all you have.
This works great and requires ordinary tools like a pocketknife, matches, and some sort of sealant.
I'd imagine the terminals to be more reliable under difficult weather conditions, slightly less likely to set off any explosives you might have right next to you, do not produce any sound/sparks/smoke when you might want to stay undetected, recoverable/reusable if the non-blown-up parts could be recovered (exercises, guerilla warfare), longer shelf-life, the only tool you need is a pocket knife, etc.
Watch 30 seconds from here and skip 6 minutes of useless chattering.[1]
The instructions say that the last step is "Insulate", so you need a roll of tape, too. Not like modern insulated splices.
I've tried the sleeves, but they are bulky, and it is difficult to see if a good connection is made.
I've also tried manual soldering but it is always difficult to align the wires with grippers, and the temperature causes the grippers to go through the insulation. And you need shrink tubing.
However, as a pictoral reference the newer documents arent as clear for me, so this online database is still very useful.
If it's just low volt, low current, low mechanical stress stuff indoors - just twist and solder and wrap a bit of elec tape around it. But if it matters, break out the crimp tool.
From what I have read high current connections shouldn't be soldered (heat may melt solder) so you crimp not solder.
Far less bulky than they appear because they shrink while being heated so they're barely thicker than the wire. They can also be bent while hot which lets you get joints into tiny places.
So far, haven't had a single one fail, although I'm still dubious at using them on corroded or non-copper wires.
Alternatively, use self-vulcanizing silicone tape instead of heat shrink. That stuff doesn't need to be put on first, and doesn't need a heat gun, but is harder to apply on small wires due to the need to stretch it as it's applied.
Don't use the shitty metal alligator grippers you get on "helping hands", they're terrible even when not heating the wire much. A small smooth-jawed vice or two is far better for small work, e.g. a PanaVise model 201.
Eg https://www.toolstation.com/ideal-industries-in-line-push-in...
For conductors with robust enough insulation (i.e. at least 105 degC rated), and assuming you're not beholden to RoHS, they make for quick, permanent, production-worthy splicing with just a heat gun...and you can actually buy them today.
Your question kind of answers itself - if they could run the wire all the way between detonator and blasting cap then they wouldn't have to splice it.
I guess you could use them for a number of other options, like tapping a line, although you'd probably be better off just twisting the wires in that scenario.
https://www.amazon.ca/Kuject-Connectors-Waterproof-Electrica...
You do need to provide external heat though.
https://www.youtube.com/watch?v=5uxsFglz2ig
I assume it would be too difficult to trigger the thermite reaction in the field with WWII tech, among other problems.
I have no idea what the composition on the outside actually is - it’s pretty slow burning at least.