I did some larger prints a few days ago ( size of about 200 x 100 mm).
The prints were quite hard to remove from the bed, even after it cooled down.
It seems like the large print is causing the warping as it shrinks while cooling down.
Now, the heated bed seems to be warped a bit. It was warped a little bit from the beginning, but it looks like it´s getting worse.
When i home the extruder (XYZ), the nozzle already pushes the bed down a bit, but when i print in the middle of the bed, it´s just barely low enough to extrude a well-sticking 1st layer. (I didn´t even print 1 kg of PLA

Is this a common problem of the 3.0 aluminum-bed?
I heard of some people who use glass as a printing surface, but i have some questions before i start to mod my printer:
- Where are the best sources for glass beds? Can i buy it somewhere with custom dimensions (covering the whole bed of the Felix)?
- How do I get the heat from the heated bed up to the glass? With a warped bed, the glass only touches the bed at the corners, so there´s just a very small amount of heat transfered. Is it recommended to use some kind of thermal grease between the glass and the bed?
- Do i need special glass, because of the high printing temperatures?
- Should I use kapton tape on top of the glass?
What are your experiences?