I looked for a filament splicer “thingi” without finding much. So I knocked this one up. Surprisingly - it seems to work! It’s based on having a hot tongue to lick the filament ends and butt them up while they are hot and sweaty. The re-shaping of the filament takes place by being forced through a PTFE tube while it’s still malleable – basically at the same time as the buttering up takes place.The first splicing set-up made a very good bond but left a flange. The next version seems to have moulded the flange back into the desired 3mm circular profile.