The entire time was spent at the sander. First, I did the spring back 10 degree bevel on both sides of each rib. This took nearly 3.5 hours. The rest of the time was spent putting the relief crimps using the oscillating spindle sander with the table set at 25 degrees. Cleanup (not included in the time) was amazing. There was dust everywhere! This is one part of the project that I'm glad to have behind me. Now I can get back to working with aluminum and blind rivets. Yippee. BTW, I figured my total time to do form blocks for the nine ribs and discovered that it basically took me two hours per rib, from beginning to end.