Because I didn’t want to mess around with several sticky pens or sprays on the glass side of the print bed I tried to adopt my solution from the FlashForge Dreamer to the J1. There I coated a borosilicate glass plate with a 60µ x 200mm self adhesive capton foil. This garants excellent adhesion to the print bed with nearly every material (except PP).
So I coated the plate of the J1 too and got a better adhesion than on the PEI coated side.
These parts were printed on the PEI side. To see is a remarkable warping of the corners.
These parts were printed on the capton coated side with the same G-Code under identical conditions. There was much less warping. The only little disadvantage is, that it is a bit difficult to remove the part after print. Even if the plate was cooled down there is much more force necessary to get the parts off the bed. But with a bit exercise this will not be a big problem.