Do you have lots of scrap lengths of (non-flexible) 1.75mm 3d Printer filament? Want to join them into a longer length?
Don’t mess about with those “fancy” jigs, they are a pain in the backside to use, never get it right. Instead, just get a length of this perfect sized silicone tube.
Take your filament and cut them square off (don’t bother trying to angle the cuts, square works fine), then stuff them into the tube until they meet, I find twisting the tube around helps screw the pieces in
Now lightly grip one of the filamertets with some pliers and give it just a bit extra of a push into that tube, this will help give the tube some tension pulling them togethor.
Grab your soldering iron, for PLA at least set to a typical soldering temperature about 320 degrees C and hold it against the tube right over the join, work it around in a bit of a swirl motion, all around the tube, with light pressure.
You’ll see that filaments begin to merge, once it looks like theyt have fully merged at the join remove the solding iron and let it cool. I find it helps to roll it gently between a wet finger and thumb or against the bench.
Now you can either cut off the tube, or I find it’s usually easy to just get your thumbnail behind it and pull ot off the length you’ve joined to use again.
Here arre some videos showing the process…
https://www.youtube.com/watch?v=kAv9FamwkxM
https://www.youtube.com/watch?v=ukN8L5rGWoI
From experience the joint filament usually feeds through just fine, but partuicularly with standrd pusher bowden tube setups it can get caught as it enters the hot end and need a helping hand, maybe my extruder is just weak, anyway, it’s best to babysit while you pass through the joint section so you can apply a bit more force if need be.
