@Oliver_Seiler consistency is great. They are giving the tolerance of what they are providing. So they guarantee it will be 0.040" thick, -0.000" (i.e. not undersized), but up to as thick as 0.065". But that is a CYA tolerance if you ask me. Mine is spot on 0.042" everywhere I can measure.
Good to know.
I have recently printed large item using the PEI sheet and was extremely happy with it. I wanted to know if the glass is really needed? I have 1/4 aluminum tooling plate which is very flat and will try applying the PEI sheet directly. I too notice the extended wait for the PEI to reach stable temp with glass in between. I also tried PEI on a .060 aluminum sheet and place over the aluminum head bed, it heated up faster than on glass but both 060 aluminum and PEI warped during large ABS prints.
@Vic_Catalasan when measured with a dial indicator I still get cupping on the 1/4" cast aluminum tooling plate when heated to ABS temps. That’s why I stick with the glass. But YMMV.
Need a bigggggg chunk of aluminum to not change shape with all that heat.
@Ashley_Webster http://i.imgur.com/77PnIXU.jpg
They are my hinged corner clips. They are on the github but you will need to tune the thickness to meet your needs based on the as-built thickness. Mine are designed as a snug fit when closed, but easily open to remove the bed.