We are not there yet . The spar is not made from 6061-0 nor any other part of the plane. Only the channel stock for the ribs were made from the 0 stock. That would not be ether if I could have gotten the coil in tempered grade. I made my statement on the artificially aged process I used . That was based on my internet search for a hardening process back in 2007. I guess you can believe all you read on the net. I could not, find that info today. However it was stated as I post . So that was what I did. Because I was not completely happy with the final rib. [ the bottom straight area ,behind the spar] subject to impact distortion. and deformation even after covering. The future creations became foam cored wrapped in channel. Though there probably is not another plane in the future. After knowing the machines I built can form even an alloy of t3 or t4 . I would search for a supplier of that grade.