I am looking to purchase some 6mm aluminium plate for repairing my scholar modified Zetec sump. Can anyone give a guide as to what grade would work best? What I need is a grade that will weld on to the original sump as well as the modified base. Anyone know of a good supplier? I am currently looking at ebay!
Regards, John.

From memory grade 5083 has the best welding properties, alternatively 5251 although that tends to be in more sheet form as opposed to plate.