Soldering, brazing, welding, getting two pieces to stick together. Clean, clean, and if you think it is clean, well clean it again.
The material you are using plays a big part in what you use to stick it together. I have irons from a micro pencil tip to a 120 watt stained glass iron, I have (3) micro torches that run on Butane, (2) gas torch sets and the small Burnzomatic Mapp gas oxy torch
Each has its best use and some you can get by with. I am also a tool junkie
I had to do some 5/16" piano wire. I tried my electronic solder, it was right there not good. It would not stick. So I grabbed the acid flux, 1/8 diameter 70/30 solder. It was sort of OK. I was using an 80 watt iron. I switched to the burnz and brazing rod. Much much better. Only issue I have with the set is those cans are not cheap and they do not last that long.
I might have had better luck if I would have used the micro torches. The solder just would not flow, if I took the iron across it, it would flow, but it seemed the heat just did not penetrate that far. When I used the torch, you could see the brass flow to the other side and fill the area between the wires.
The surface area of the irons tip plays a big part in how it give up the heat. Of you have the pencil point, there is not much area to send heat into the material. You can add to the area by letting a puddle of solder form and that will help send the heat into the part. On the bigger iron, they have the chisel tips with a big flat area to send the heat.
https://www.amazon.com/dp/B000GR3NMY/
Here is the burnz torch set. Took me a couple of bottles to figure out to use it.
https://www.lowes.com/pd/BernzOmatic...h-Kit/50126405
I bought a set from HF when they were $99.99, but it did not come with the tanks.
https://www.harborfreight.com/portab...nks-65818.html
Depending how much a set of small tanks costs, would make simple work out of brazing 3/16 wrapped wire. Actually, would be over kill. But I have used it for other things so it has paid for it self in reduced frustration.
https://www.amazon.com/ARKSEN-Acetyl...+acetylene+kit
I have the older version, mine is orange. I must have gone through 5 or 6 of the butane bottles with this. Best heat shrink shrinker I have used.
https://www.harborfreight.com/Butane...rch-63170.html
I once had the bright idea I would mig weld the 1/4' Piano wire. I turned it down as low as it would go. Lowest heat setting, lowest wire feed speed. It would blow through if I held it for more then .00000000003 second. You would need to be a lot better welder than I am. I am sure it could be done, but not at my skill level.
Buzz.