Dennis,
Just use standard lead-tin rosin core solder. It isn't for mechanical strength, but for good electrical (and non-corroding) contacts. There should be no stress on these solder joints, and to some extent, they are supported by the heat shrink tubing. I always extend the heatshrink tubing a cm or so past the place the insulation stops. This is to stiffen up the very flexible wire so that the rock solid solder joint near the edge of the insulation isn't a stress point.

Remember to tin everything first (wire and pins), then solder. This gets the wire nicely wetted (especially the many-stranded stuff), and makes it a lot easier to make a good contact with the connector.

As long as you get a good connection, the resistance will be negligible. Remember your motor probably has a 1/2 meter or so of 18-20 gauge wire in series with this very short solder joint.

Clancy,
Actually before I posted I checked my solder roll, but the label had fallen off. I vaguely remembered the 60-40 but didn't want to give the incorrect %. However I defer to your expertise!

Has anyone tried working with a conductive paste in a non soldered joint? One of the problems I've had was with the stranded wire becoming very stiff once soldered making neat short run wiring difficult. Just wondering if there was any alternative that works for our loads?

Best,     Dennis

A tip.  If you are worried about the solder wicking up under the insulation, try clipping a metal heat sink (forcups or any metal clip) to the wire against the insulation.  This will retard the solder wicking up the wire and leave you with more flexable leads.

Clancy