: I had this idea bouncing around on the back burner
Ken,
It's a national sickness I tell ya. Folks running around thinkin' up ways to do strongbacks. Why durin' the recent thread on aluminum strong backs I started cogitatin' on steel studs myself. Cheap and straight, only problem's that open side of the "C" channel which permits twist. The bouncer in my brain was to spot weld short lengths of light weight plate lip to lip, say every couple feet. No welder, use epoxy.

I build docks with 3" by 8" 16 ga. "C" channel. The channel is part of a system which together with angles and brackets is designed to be bolted together with 3/8" fasteners. As I got the material "used" by the dumpster, I didn't want to spend money on all that hardware. I found by welding the channel together I got a lighter and more rigid structure than the bolted up sections. I think this is because the bolts can move laterally in the prepunched holes that are slightly oversized. I think you'll find welding or bonding the studs together cheaper and stronger than all those rivets.
Be well.
Geo. C.