Canoe wrote:< 50 VDC
LED or other lights, eBike drive, swamp cooler fan & pump, Photo Voltaic, wind power, ...
both wire splicing and for sealing the wire/conductor connections to the back of plug-in connectors
hot glue gun - hmmmm.....
when cured, is this rigid or flexible for thermal cycling under use?
happen to know the temperature of the glue for application? (wonder if it, like soldering, would affect a quality crimp)
With so many different applications in mind, I don't think there is a single correct answer.
For wire to wire connections that wont be submersed in water, and pretty protected from the chance of rain/spilled beer, I'd say solder and normal shrink wrap is great.
I'd say the same for most "plug in connectors". Especially if your not going to be plugging in and unplugging often. If it is a connector that will be unplugged often then try to find connectors with some sort of strain relief. Another option to create extra strain relief is to layer really small shrink wrap over just the wire but not over the actual solder joint. Then layer thicker shrink wrap over the actual solder point, and the layered shrink wrap.
For photo voltaic panels and wind power turbines I have no experience, but figure you'd probably want to follow 12v auto mobile wiring practices.
As for using hot glue as an insulator/separator it works great. Hot glue specifically for "fabric" is very very flexible, I like it a lot more than the clear-ish 'normal' hot glue. I don't know about gluing over a crimped connector. Most crimped connectors I've used have some sort of boot or other means of protecting/insulating, or I'd just use shrink wrap.
I don't know what temperature the glue melts at. Though, when you're at the store there are 2 options what temperature the glue gets to, High Heat and Low Heat. A 40 watt soldering iron tip will melt the "high heat" glue.
Do you have any specific connectors in mind?
Can you find them with factory attached leads, that you can solder to?