Yes, I'm wandering the same thing. Can someone help us out?

 

I have worked on a multitude of electrical systems from Navy aircraft, TomaHawk Cruise Missiles, MX Missile, Space Shuttle flight hardware and a varieety of other things including Wastewater Treatment Plants, Atomic Reactors, and cotton mills as well as gigantic Amusement Parks. And also have been certified to NASA Soldering Specifications for Flight Hardware.

You could do anything from just forming loops in the wires and bolting them together with a nut and bolt insulated with good tape or a variety of other nonconductive materials.

You could use a good solid uninsulated butt splice and insulate it.

Or you could do a good solder job. Any solder job is supposed to have a firm mechanical connection and not depend upon the solder to keep it joined. The solder is just to improve electrical conductivity as a solid conductor.

Most modern connections are crimp type going to a fixed terminal board or strip. This ensures both mechganical and electrical connection is maintained.

It really depends on what you have available.