Well, it's really not that important, but I was just wondering. Probably 316 I would imagine for marine use.Sorry for the delay to reply (was off a few days!)
Well what grade of aluminiu I used is a really good question because I just don't know.
The only thing I know is that those aluminiun is coming from my brother who use aluminium to make boat (a pretty big boat fact) i dont know the grade is needed of alluminium for boat, so... Next time i see my brother I'll ask