Quote Originally Posted by jpmassey View Post
I sanded and then SS wire brushed it. The edges are plasma cut, so that probably didn't help.
"Plasma Arc Cutting, Beveling, and Gouging:

This process has some limitations and must be carefully controlled. If it is used, it requires the power source to be set (DCEN) along with the use of small orifices to gain high velocity and concentrated heat. Heat affected zones will be crack prone particularly for 2XXX, 6XXX, and 7XXX series alloys and will require 1/8 inch or more of mechanical surface removal before welding. Series 1XXX, 3XXX, and 5XXX alloys are not as crack prone and can generally be welded as cut by this process."

From the Link