this is probably a very stupid question
can u mount the controllers directly on metal
probably not
can you use just little plastic (nylon) washers or do u need to mount it completely on a piece of lexan
can u mount the robot controller and breaker panel directly on metal
can u just us small plastic ( nylon) washers to mount or do u need mount it completely on a seperate piece of lexan
They are in plastic, insulating cases, therefore, you may safely and legally mount them on metal.
Try not to double post, you question won’t get answered any faster. 
Your question was answered here: http://www.chiefdelphi.com/forums/showthread.php?threadid=33821