A 3D-printed hollow tube has a wire ferrule inserted in the end, which serves as the tip of the device through which solder is fed. The tube has a cutaway, which allows the user to feed solder ...
The solder feeder uses a Bowden tube, with a 3D-printer extruder motor pushing the solder wire down a PTFE tube and finally into a fine aluminium tube from which it’s fed to the iron tip.