posted by [identity profile] metahacker.livejournal.com at 10:48pm on 2007-03-09
This is all theoretical. I have no hands-on welding knowledge, but I know metalworking otherwise.

3 is easiest to do, and fastest. Cut, clamp, weld. The square edges help you line it up. at 90.
2 is hard to hold steady while you weld it. I'd be sure to screw it up and get a 88 degree bend or one where the two pieces are twisted with respect to each other.
1 may be weakest if you've deformed the metal to the point where it is weaker at the flap.
"4", which is "cut a line halfway through, fold at 90 degrees, weld", i.e., sort of 4:3::1:2, strikes me as even easier. But depending on gauge you may get a ripple at the end of the cut that you have to hammer smooth.

 
posted by [identity profile] dglenn.livejournal.com at 11:16pm on 2007-03-09
I was looking at stock 1/8" thick -- in any case, it'll need to be thick enough for the threads I tap in it to hold the stuff I want to mount securely. (I'd really like to use aluminum for ease of cutting, ease of tapping threads, and lower weight when finished, but I understand aluminum is a major PITA to weld. So I figured I'd use steel.)

The sides can be ugly as long as the front lines up -- pretty would be nice just because pretty is always nice, but isn't important enough in this case to worry about -- I'll grind off dangerously sharp bits left over.

I hadn't thought about the bending making the metal weaker than a weld -- but that sort of thing is why I'm asking folks with a clue for advice instead of just guessing.

My brother pointed out the difficulty of getting #2 straight; I was thinking that there ought to be a way to clamp the pieces in place beforehand (maybe using a pair of vices?). I thought of #1 as a way around the difficulty of keeping the pieces aligned in #2 and the offset resulting from #3.

Your suggested #4 does sound easier than accurately cutting the notch needed for #1, and has the advantage of a lapped joint to work with for more contact area, if that matters.

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