Riveted side hinges
I put some high-temp RTV between the firewall and side skin and riveted on the side hinges. It was a little difficult to get the RTV in there. I used a popsicle stick to open up the gap, and a strip of scrap aluminum as a putty knife. Worked really well. The only hinges left to attach to the firewall are along the top. Those will wait until the forward top skin is ready to attach, which is after all the wiring is done–way down the road.
There was a suggestion on the forum about using extruded hinges for the cowl. They are a bit more expensive, but I guess they are less prone to cracking. I’m not sure if I’m going to stop progress and order some of them or not. Some people have had trouble with hinge loops breaking off. A couple of suggestions I’ve read are to make sure the hinges are not pre-loaded and to deburr the corners between the hinge loops. Decisions, decisions.