Or some 5/8" square stock.
I've answered posts in the marketplace and started a thread, I'm just dropping this here hoping someone who doesn't frequent the marketplace can help me out.

I'm wanting raw steel.
It's gonna get welded to.
I'm building a rack for the milk crate with a upright and a shelf over the tail light.
I've got the square tubing, but I don't want to wreck my sissy bar. I need about two or three feet of 5/8" square stock, that should be enough to cover the losses of the learning curve while I try to get it right. I really don't want to buy 24',, which is what I had to get for the tubing.

It's not 5/8". And it's not solid. The bike shakes. Hard.