I work at an Aviation company and see quite a bit of aluminium sheet and stainless off cuts thrown in the scrap bin if you have a need drop me a line and I will endevour to see whats around. Mostly the fasteners are UNF threads so not alot of good. Solid Aluminium rivets. sheet alli is mostly "clad" meaning there is a soft pure alli coating about .004" thick both sides(scratches easy but corrosion resistant) Not for sale just need to cover postage. Andy P