Tube Notch Practice

I'm doing some tubing notching practice before start building a fuse to see which method works best for me. I've done some whit my cheapy Harbor Freight tube notcher tool and some manually with a bench grinder. Result is the same! During progress i will post you how i do!
First of all i clean tubes, where cuts and welds are supposed to be, with a sandpaper. I use that has fabric on the back side and 180 grit. I use these sandpaper only for steel tubes and not with other materials to avoid contaminations. Than i do a mirror finish, with a dremel steel brush.