Using 3/4" pipe, I made some 90° bends, and man was I pissed. Those aren't rust marks, it is orange paint off the die:
Brand new, 3/4" sch 10 from the Big Store. I figured I'd get the Chinese stuff to use with my Chinese bender. The results were as shown. That is beautiful. I don't understand all the talk about mandrel benders, who needs one with such nice results as this.
Anyway, here is the next attempt. Can you see why it is OK?
That's right, it's American pipe. Dang! i usually don't badmouth import stuff, you usually get what you pay for. But this stuff sure as heck won't ever be used on any more gas, or other piping, that I ever do. Son of a you know what!
So no, I am not badmouthing my Harbor Freight bender, it does exactly what I expected from it.