We used to use these in the 1980s on our combined cadet force field days.
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!
That brings back a lot of memories. I too laid a lot of cable, and as well as field telephones we had 18, 19 and 88 sets. My first introduction to radio communication.
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.
CCF, what a fever dream that was. Give a bunch of teenagers guns once or twice and they will march in formation every Tuesday after school for reasons unclear even to the teacher-organizers.
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.
My school had the option of the Duke of Edinburgh's scheme instead. I chose this because I didn't want to wear itchy uniforms once a week and be shouted out by teachers who seemed to have fond memories of National Service. I eventually got to meet Prince Phillip, who asked me whose heavenly bodies I looked at using the telescope I'd made on a D of E project.
We had DofE too! Did my Gold in the Black Mountains. Didn't bother to meet Prince Philip as I was/am staunchly antimonarchist, much to the dismay of my mother.
I think this must have been dependent on the school/location as I was also in an RAF section and we flew in (small) planes maybe once a term.
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)
My cousin chose RAF and got some single-engine flight training. This was early-90s. I don't recall exactly how much of his private licence it helped with, but it was a fair bit.
i had my days like that too, every 2weeks the big boys would arrive in a couple deuces full of thier own toys, so they would go on maneuvers and we had more to polish and clean up.
I've used a similar technique I learned in the oilfield to join or repair solid conductor and stranded wire breaks.
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.
Wow, a mystery solved 40 years later!! Found some of these in a box of
bits on an RAF base when I was a kid. They were on some signalling
gear with headphones made of electromagnets and thin circular iron
plates in the ear-pieces. The cotton braided wires had been joined
with these weird copper pipes and then wrapped around with electrical
tape. Obviously a field repair thinking about it now. They were surely
the same tech.
Pardon my ignorance, but how would this fare against a simple, purely mechanical connection, like wiring terminals, like the ones used for home electrical installations? (Or more specialized ones, since we're talking Military Grade.)
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.
Resistance of the soldered connection will be consistently lower compared to terminals, also terminals with screws, especially in WW II quality, will oxidise quickly in a wet environment and thus the resistance will go up over time. Plus you get a very nice visual feedback by the self-soldering joints. Terminals look all the same - you need tools to control the quality of the electrical connection. So for longer lines with several joints that are needed for more than a few days, I‘ll definitely put my money on the soldering team.
So, today, what is the most practical way to solder two wires in a straight line?
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.
Not to solder, but to use a crimped connector - the good ones come with hot-glue-lined heat shrink so you crimp the wires for a great connection, then heat the connector and the shrink glues itself down, making a totally sealed connection.
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.
Just use a Wago connector no soldering needed. Not everything has to be or should be soldered so maybe the question should be what to use for which situation?
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.
Not sure if that's what you meant, but there are small heat shrink plastic sleeves with low melting point solder in the middle. You can heat it with a heat gun and the solder will melt, joining the two wire together. They're often used to fix lawnmower robot perimeter cables. I find them very useful, reliable, waterproof and they are barely wider than the wire itself.
I recently used those to repair a friends scooter (a cheap knock off of the Xiamomi M365). Water ingress through the charge port seems like a foregone conclusion and it shorted some wires running from the motor controller to the dashboard PCB, frying both. I swapped out all the JST connectors for marine grade solder sleeves. It's less "repairable" now, but hopefully a lot less likely to need repair in the first place.
Yeah, that's what I meant, but I don't think they work well if you have to solder more then a few parallel wires because then it gets really bulky. Not really good for production work, imho.
I've tried to make a thinner splice on a four-wire cable, by staggering the joints. But I found it was too difficult to cut, strip, pre-load heat shrink, twist wires, and solder without melting the adjacent heat shrink. I think it's doable if you really need it, but I was just experimenting, so I gave up on it.
Put heat shrink on first. Then make a lineman's splice. If appropriate (solder can cause a stress riser in some cases making vibration problematic) solder. Then slide the heat shrink tube up & shrink it.
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.
Reminds me of SAE AS83519/1 series shield terminators, which contain a Sn63 solder ring preform and flux in the middle of a translucent PVDF heat shrink insulation that seals on both ends on application.
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.
You are a saboteur trying to blow up nazi assets in occupied territory. The only equipment you're able to bring to the site of detonation is stuff that will be unobtrusive under your street clothes, since the enemy and collaborators are everywhere. Wire itself is considered war materiel and not readily available.
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.
Not necessarily for explosives, or you might want to wire your explosive into eg a switch to ensure it triggers under the correct conditions. From TFV, they are an invention of a saboteur division.
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.
I actually have some of these kicking around in a parts drawer for the last couple of years! I picked them up as a curiosity, need to get around to trying one out on camera, see how strong the joints are, if they are still viable, etc
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!