I recall that there were reasons why some processes benefited from 6061 aluminum while others preferred 7005.... and why 6061-T6 was decent.

My wife has just acquired an aluminum Cannonade ST600 built in 1987 and I checked out the vintage Cannonade catalogs from the 1980s curious to see what grade of Aluminum the frame is made of.

No information. I am supposing that it is probably the 6061-T6 but I'd like to know.

Do any of you vintage Cannonade owners know what aluminum alloy Cannonade most likely used back in the 1980s ??