In article Xns95B371897FDFAgeoffschultzorg@
204.127.204.17, says...
I recently purchased a Questus self-leveling radar mount off of Ebay.
Unfortuantely this unit was designed to be mounted on a backstay, and my
boat (a Freedom 40/40 with a carbon fiber mast) doesn't have one. I've
designed an adapter for it, which I will machine out of 3" round Al stock.

It seems that there's primarily 2 types of Al stock available: T6511 and
6061. The part will be painted. Which of these (or some other varient)
should I use considering the salt water marine environment?


T6511 is a specific heat treat designation for 6061. 6061
does fine in a marine environment. IIRC 5086 is the
preferred alloy for fuel tanks, etc, but is more commonly
seen as sheet and plate.

Ned Simmons