I recently purchased a Glimakra 2 shaft band loom so that I can weave narrow bands more easily. I have been experimenting with how to also weave pickup patterns on this loom.
Although there are only 2 shafts on this loom, resulting in a tabby type of weave structure, you can also add another warp thread that does not go through one of the heddles. The warp thread rests on the front and back beam and does not move when the sheds are raised and lowered. The extra pattern thread sits in between the 2 threads that go up and down. This makes it possible to manually pick up or raise the pattern thread so that it shows above the ground weave. The pattern threads that are dropped, then move below the surface to the underside of the band.