On the Blue Jeans Cable locking banana plugs I use, there's a "well" between the two set screws where one would solder the connection. It's used by them for their ultrasonic welding of the cables they make and sell. I have two 60watt soldering stations that use in tandem to get the soldering done on the cables I make. There's nothing but metal, no plastic to melt.
KEF R500, R200C, R100, R50, SVS SB2000 sub, NAD T758v3 AVR, LG UP875 4K BlueRay, Samsung UN55JU6500F 4K LED TV, KEF M500 headphones, Sony CDP-CE500 CD changer. Office: NAD M10, KEF LS50, KEF Kube 10b, E.A.T. C-Major TT w/Ortofon Quintet Blue cart.