How to stiffen 1/2" aluminum tube?

[intarsiabox]

I would just brace the bend with two pieces of aluminum flat bar. Just put a piece on each side of the tube at a 45° angle so the bend now looks like a triangle, drill a say 1/4" size hole through the bars and tube at both ends and put a 1/4" bolt through the holes and tighten up with a nylock nut. This method does take up some real estate on both the horizontal and vertical part of your tube and I'm not sure how much you have to spare. Hope this made any type of sense at all.