I had a boom arm that was industrial pipe, and it worked, but even with a stabilizer cable, and with a much shorter arm, it still had more flex than the much longer one that I got from Andrew. I just waited until he had a good sale, then picked it up and sold mine. It was definitely worth just getting it from him, so I didn't have to worry about it. I had already upgraded the rest of my kit, so all I needed was the boom arm.
I made a good stabilizer cable myself, and a much better pull cable also.
I have a magic arm also, but it is nowhere near as good as my Matthews extension. This is it - gives me tons of extension and its strong. https://www.bhphotovideo.com/c/produ...Extension.html