Filament Welder

I've printed some pieces to use as part of a rig to weld scraps of filament together:

The scrap filament enters the PTFE tube from the left and the filament from the takeup reel enters from the right. A few seconds of lighter flame in the center of the tube, followed by pushing the two filament strands together and they become one. Wait for it to cool down and push and pull till the welded bit comes out (which is thicker than normal, but just where it is welded), then you can feed the rest of the fragment through the tube and wind it up on the takeup reel.

A close up of the PTFE tube support where the welding happens:

The M6 nut trap holds a nut very securely. I had to use an M6 bolt to drag the nut down to the bottom of the trap. The PC4-M6 coupler then screws into the M6 nut from the other side. I cut the PTFE tube and shoved it into the couplers first, then located the right place for screwing down the supports to hold that length of tube straight.

I also use these spool rollers for both reels of filament.

I tried various sources of heat do do the welding, but a few seconds from the butane lighter worked infinitely better than anything else, so I'm sticking with that.

Because this produces thick spots in the filament, it probably won't work with a bowden setup, but a direct drive should be OK (so perhaps I can use these reclaimed scraps in my old solidoodle.)

When I'm done welding fragments, I can pack up all the bits neatly: