Following up a post from Leav:
Reporting on a new (?) bed material for printing on without a heated bed and an improvement on an old extruder design:
I believe that the paper that was used is known as construction paper, which is used for making architectural models.
I have managed to get some good prints with no warping using ABS on this paper. There is a small amount of paper residue attached to the print but this can be removed with a little water.
I have found that adding an extra half a layer height between the first and second layers ( because the first layer is very close to the paper surface) adds to the quality of the print.
