This is a bench splicer or in situ splicer for Anet A8.
It is a rework of TrustFm's "Filament Splicer Joiner":
The head of the TrustFm's FSJ was used and placed in a C bracket. Make sure to have some M3 nuts and bolts.
The two photos above show the splice helper used on the bench with solvent welding and in situ at the printhead of an Anet A8 for heat welding.
Solvent welding with methylene chloride works, two minute set time and half hour minimum cure time. A bit fussy but it works. $9 gets you a quart of Jasco Premium Paint & Epoxy Remover at the hardware store, it's mostly MeCl2. Here's the MSDS:
Otherwise, for heat welding, I put aluminum foil on the tip of my soldering iron, set it to 650, and very carefully sculpt a weld. This is a lot faster than solvent welding. I say sculpt because the finished weld must not be wider than the filament and cannot be too narrow or the filament will hang in the wheel and gear and not feed. Any bulge can hang up on the guide hole to the gear and wheel and the spice will break or the gear wheel will grind the filament down and the splice will not move through the hole.
Thanks again to TrustFm's head design! Again, make sure to have 2 M3 nuts and bolts, at least 6mm long, to put in the head. The nuts fit snugly and make sure the hole is cleaned out to dimension, I used an eyeglass flat screwdriver to scrape off the excess filament fluff around, in, down, and at the bottom of the hole.
I really want an in situ splicer at the print head. The difficulty is the filament wants to bend and the two pieces do not want to meet up. You might want to try TrustFm's technique also, it does overcomes the bending problem, and it uses a heat weld.
Raft 12 mm, wall thickness 0.6mm, and a table with blue tape. The new blue tape, 3M Platium Painters Tape #2098, is plastic and needs to be applied carefully. I like it better for wear than painter's blue tape (I can only get about 15 hours and the painter's blue paper tape needs replacement). The surface finish is smooth with the Platinum Painter's tape, not rough like paper painter's blue tape.