One the jobs I had in my youth was working as an installation tech for the Australian Broadcasting Company. Our main job was hooking up everything for each new studio. Like @biminiroad, I’ve probably soldered hundreds of thousands of connections in my working life. Every audio, video, intercom etc. connection had to be soldered, and there are more than you can imagine for a large studio. I would spend weeks working on each patch bay. It’s definitely a skill that takes some practice.
Yeah, I have some friends whose day job is studio equipment installation and they are by FAR the most proficient with a soldering iron.
Are you an Aussie??
My family moved there from the States when I was 17, and I stayed till my mid 20’s. I lived in Sydney, went to the University of New South Wales, worked for a music store, the Australian Broadcasting Company and Sony. I came back to Louisville because I had family here, and worked for a hi-fi store the went to work for Xerox where I stayed until I retired a few years ago.
I’ve done quite a bit of soldering in my day, but most of the recent stuff has been working on the guts of guitars. I currently have a set of pickups that I want to swap out on one guitar, but haven’t done it yet as I only have 50/50 solder and no flux.
Everything in that video is pretty much relevant today still though, and while it seems easy, there’s a lot more to doing a good job soldering than just putting an iron and some solder together as the video points out.
Often solder has built-in flux. Not the case with yours?
I really want to get some more Curtis chips and make a polyphonic analog bank of oscillators 
You just like the curtis sound?
I usually don’t get flux core solder as I’d rather get the flux on first rather than at the same time.
When I was a kid I used to watch my granddad solder - he would dip the solder in flux paste and apply it with the tip of the solder before soldering, and I like that workflow and it makes a good joint.
I don’t like using the 50/50 as the extra heat isn’t good for the insulation on very thin gauge wire, but I like to get a good coverage of flux on the exposed wire before tinning it so it doesn’t become a sleeve that the wire can later become detached from.
Probably personal preference more than anything else as I know a lot of people who will always use flux core.
Yeah I like flux core - it’s convenient and you can be really quick with it when manufacturing. If you’re careful you can make sure it doesn’t spit everywhere. But totally it’s all about what works for you! 