made my tray from some carbon fiber cloth scraps I had laying around ,depron foam and some good finishing epoxy...4 layers of 3.7 oz 80/20 cloth seems plenty thick .I made the bottom thicker with depron foam between the 2nd and 3rd layers so I could notch the bottom out for the mud guard nuts on my Cen MAtrix chassis. There are a couple pics here
http://www.rc-monster.com/forum/showthread.php?t=4994
pinolelst