Hi, I'm performing tension tests using a dog-bone specimen conforming to ASTM E8 on 6061-T6 extruded aluminum alloy. ASTM E8 says the surface preparation should be as the product specified. The material I ordered is low grade bar stock 2" wide by 0.25" thick. If I am going to reduce the thickness of the material from 0.25" thick to 0.125", I'm wondering how the surface should be prepared and whether surface prep really impacts the tensile strength of the aluminum. Any advice or references to literature would be very helpful!