http://www.evga.com/forums/tm.asp?m=365730&mpage=1&key=&
And here is the reason why. I lightly lapped my OCZ Vendetta 2 just to flatten a raised middle heatpipe which was about .5mm higher than the outer ones. So I went with 400, 600 and finally 800 grit sandpaper and I wanted to polish it. as I applied the polish and lightly pressed on the base, it caved in and cracked. here is the proof:
And the image of the result.