Grades of aluminium

hi all

im looking in the near future to buy some aluminium sheet, however i dont understand the graades they have? can someone help?

also could someone recommend a grade to me that will be suitable for a base? and where it is avaiable from?

thanks alex

6082 T2 (also called HE30T6) would be about the best, HE15 is softer. Also anything with a 6 or 7 at the start is a good bet.