The skin for the left tank seems to be harder to work with than the right tank skin was. This required a totally different approach in assembly. It worked out that it was simplest to put ProSeal on the skin and ribs, then clecoed the bottom of the ribs to the skin , insert the skin into the jig and then clecoed the top of the ribs to the skin. Did ribs 2-7 at the same time (one shot) worked great Kevin and I finished riveting the ribs in 2 hours.
