Custom bottom engine bracket

The bottom firewall mounting channel CF-CHL-023-C-A- is 1.2mm thick. It fits between the lower engine mount and the floor skin at the front, yet these two meet at the rear. It creates quite a large gap for rivet stems to (unsuccessfully) pull the layers together immediately behind the channel. I filled this 1.2mm gap with stacked layers of 0.63mm sheet, with some tapering at the aft ends of each of these pieces. Using 2 layers was much more consistent with my attempts to taper a single 1.2mm shim. When assembled the "fill" is much better.