I don't see how solder could improve a crimped joint.
I've some theory behind it-higher conductivity area ~ lower connection resistance
![Wink ;)](https://www.eevblog.com/forum/Smileys/default/wink.gif)
Preparing welder transformer secondary connector on 6mm in diameter copper strand wire and for testing purposes I've used classic (old) vice , and patent pending
![Evil >:D](https://www.eevblog.com/forum/Smileys/default/evil.gif)
screw cut into two pieces, so when copper pipe was pressed by screw forming copper connector into circular shape and prewenting flat pressing, I've got decent results:
![](http://s30.postimg.org/e6ydzr44x/6mm_strand_wire_copper_connector_pressed_in_vice.jpg)
However (it is not cleary visible) I've made also ~1.5mm hole in front of connector, to be able fill empty space from connector hole side by solder inserted throuught this small hole, while connector is heated from hole side.
I expect, strand small wires soldered to connector from front and not too much penetration to wire after connector since there will be lower temperature, so solder will rather be kept in front of connector.
Additional connection area made with solder this way, I hope, it will lower down total connector resistance even more and while this wire will not work in high vibration environment I do not expect any flexibility issues-of course thermal heatshrink will improove rigidiity w few centimeters around connector.
I will have a chance test this connection during test welding tomorow and meantime I will make this experiment with 2.5mm2 connectors in crimped vs crimped and soldered version
![Popcorn :popcorn:](https://www.eevblog.com/forum/Smileys/default/EatingPopcorn.jpg)