Hi Bernie, I have an aluminium bodied AC Superblower which I have given a brushed finish with the two polished stripes. I got this idea after seeing the Kirkhams finished this way. I started off using P120 grit paper on a DA sander to removed the main scoring created at the welded joints. Down the middle front to rear I went to P240 on the DA, then P400, P800 and then P1000 grits. I then used a cutting/polishing compound called Nuvite polish. I initially cut the aluminum with 'C' grade' then a finer Nuvite 'S' grade and that brought the mirror finish out. I then masked off the striped and casrried on with the brushing on the rest of the car. I used a finer grit, P240 but brushed this by hand front to rear. I finished the process with the red scotchbrite pads to give a silky sheen. The whole process took me many hours, I would estimate 400-500 hours in all. You need a lot of patience and it takes some commitment but gives you a great deal of satisfaction when finished. I hope this help you.
Below are a couple of links to images of my car body. Hope this helps you!
Regards
Gary