Got my Prusa as kit build from my nephew.. it has from what I can tell a 8.5x11 " bed..had to replace with
200x200mm.. but would love to get the same one again.. but I cant find one anywhere..
I got a silicone heater pad 300x200mm from robotdigg and bought a 320x220x6 cast aluminum plate locally. The plate is heavy, maybe to much for a moving bed. But a thinner rolled aluminum plate of this size is most probably warped and difficult to print on.
