Buy a set of feeler gauges and make sure that your z-axis home is set to 80% of your nozzle diameter. I have a .5mm nozzle and I home z at .4mm from the bed, measured by gauges. I’ve had much better consistency when I stopped using paper as a measuring tool.
Just use hairspray!
After I started using a first layer thickness of ~150% in Slic3r I found it sticks better, but you still need temp/levels etc dialed in first.
Try hairspray. A light coat of tresemme or aqua net on plain glass works awesome for me. The hairspray on glass makes the bottom of your part really smooth versus the lines left behind by the seams of kapton tape. I usually print in a room that’s 20-22C, with the bed at 90C and extruder at 225-230C. Mirrored glass also helps as the metal foil on the mirror helps transfer heat to the glass.
Also make sure your plastic is getting squashed onto the plate. It is better to trim the bottom of your part after printing than having it come off of the bed. And do not use extreme hold hairspray because it will bake your parts to the glass and you have to scrape them off after the plate is cooled and might break the plate in the process
My experience with hairspray on PET tape over glass is that it shrinks the bottom layers. By a lot (1mm less on 32mm wide). The @LulzBot people noticed the same thing. Maybe it doesn’t on Kapton, I’ve never tried it. Since switching to ABS juice I have no adhesion problems.
@3dpod_3D_Printing_Se yes there is a lid and it does not effect the belts or motors. I got the plans from soliforums. Will post the link this evening.
@3dpod_3D_Printing_Se here is the link to the enclosure I built.
http://www.soliforum.com/topic/1588/my-easy-and-relativley-cheap-sd3-enclosure