Thanks very much for the compliments. Yes, welding would be the obvious choice here. And while I do have access to a buddy who's a professional welder, I wanted to try this w/ just some common tools instead. Like I said in the initial post, I could have reduced the number of rivets from 6 to just 2 in the top of the half-pipe. Especially if I used slightly thicker sheet and a little epoxy or JB Weld to bond the sheet to the arcs made of flat bar. I don't know if I'd trust it to last long once in operation w/ the heat the bulbs put out if I just used epoxy and w/o at least 2 rivets. You could use smaller rivets though, for sure. I chose larger as I thought they actually might detract less, being flatter than smaller ones. Personal preference though. The 3 rivets in each end cap would probably be unavoidable but I used smaller ones there anyway.