[68commando]

A2Carat,

I too am new to this polishing. Several things you may try, polishing a wheel poses different problmes than bike castings too, you have issues getting in the lip and other tight places I don't have to deal with. I am using a rotary orbital sander I got and start out with 220 paper, the finest they make for it. That seems to get out all my old file marks and most of the imperfections of the castings. If you have a really rough casting you will have to start out with a coarser paper. Then I go right to hand sanding with 360 and at this point, I see low spots come out after the 220 scratches go away, I don't seem to be able to get out all these low spots, if I get them out in one direction, others come back while sanding in the other direction, so I leave it to just getting out the 220 marks. Then of course I go on to the 400 or 600 wet and dry. You will probably see 220 marks coming back out you missed with the 600, just go back to the 360 and get out the 220 marks, you get the gist. Then I go to 1000. I didn't get any 1200 and am not sure it would do any better, my castings are not such good material. Then I buff with black compound using an 8" wheel on an old oil burner motor I mounted an adaptor on. It doesn't have a lot of HP (1/12) but it turns plenty fast (3600) and it is not much of a job to get a shine to come right up. I use the black, brown and then the white compounds on different wheels, but to tell the truth, I don't see that the white does that much. Look at the "Sandpaper vs Greasless compounds" thread and you will see pictures of what I have done and recommendations from others that was quite helpful. You can see that I do not get a true mirror finish, but I do get a good reflection if a bit blurry, see my pictures in the other thread. I don't think it is possible to get a true mirror shine with my castings unless I plate them which I don't want to do. I have shown it to others and they are impressed, they are really impressed when I tell them it is almuminum, they think it is polished stainless right off. The work looks plenty good from 3 feet or farther away, but who is going to get up to my bike and look at it from 3 inches with a magnifying glass to see the imperfections.

If you are only going to 400 with the compounds, you may have to go to a finer grit (sandpaper) before polishing. I would try at least to 1000, try a section and see if it makes it up to your standards. See the top thread about the Motorcycle polishing 101, which is a good reference too.

Dave