If you do any reasonable amount of 3D printing you will accumulate short pieces of filament from the ends of rolls. The pieces will be too short for another print job but too long to throw out. This filament splicer jig allows ABS pieces to be rejoined into useful lengths and/or rearranged for interesting colored patterns in printed objects.

Print the “Filament Splicer” and “Cutter Guide”. Clean out the hinge holes using a 3/16” drill for the base and a 7/32” drill for the two top pieces. Cut a section of 3/16” dowel the length of the base for the hinge pin and press it into place connecting the base and the two top pieces. A pair of binder clips will be used for the clamps. Clean out the filament holes in the Cutter Guide using a 1/8” drill for the 3mm hole and a 5/64” drill for the 1.75mm hole. (If you have a numbered drill set or a metric set that could be a better option).

Using the “Cutter Guide” a controlled 75 degree cut can be made in the end of the filament piece. It’s useful to rotate the filament so the natural curl from the roll will tend to hold the cut faces together when splicing. Cut the ends of the two pieces to be joined. A single edge razor blade is used for cutting. It may be useful to tap the razor blade through the filament using a piece of wood or a mallet.

Slide the filament into the clamp with the cut faces lined up and clamp with the binder clips. Then using a toothpick add a drop of acetone to the joint. Flip the clamp over and add a drop to the other side. Let the splice set while the joint fuses and dries.

Note: The spliced joint won’t be as strong as a continuous piece of Filament so take care when handling a spliced piece. The splices do feed through the extruder nicely.

Note: I’ve only tested the splicer with 3mm ABS, but it should also work with 1.75mm ABS.