In the first test the Kapton is unsanded. The printed object sticks pretty well during the build and pops off easily when reaching the conveyor belt’s end.
In the second test the Kapton is sanded with 220 grit sand paper. While sanding clearly works well with the Kapton in the MakerBot heated build platform, I could not tell if it improved anything with my belt Kapton.
During both of these tests the belt was not under much tension. This allowed the edges of the belt parallel to the direction of belt motion to bow up. I believe the air gap between the belt and build platform due to bowing left the kapton belt at a lower than ideal temperature, reducing the adhesive force.
Further research questions:
-Does sanding help with this material?
-Does thinner aluminium help?
-Does thinner belt material help?
-Does tension solve the bowing problem?