by DCASonex » Thu Aug 27, 2015 9:25 am
To add to Bryan's comment. Polishing while sheets are flat on table allows using more pressure which greatly speeds up the process. As Nuvite describes it polishing is a process of moving molecules of metal from microscopic high points to low points, which they call healing the surface. More pressure makes this go much faster. Discussed this with folks at Nuvite booth couple of years ago, and they confirmed that this works, but generally warn against using higher pressure for fear of someone doing so on a finished section and ending up with all the ribs showing. Did not pre-polish skins on my first wing, and seemed to take forever to get it to as good a finish as was quickly achieved when skins for second one were polished in the flat. Quality of polished finish is deceptively hard to judge. After just a couple of passes, the finish becomes so much brighter than stock that it looks pretty good, -- until you put it next to a part that has been more extensively polished. If you have not done much polishing, take a small sheet and CLAMP it on table (so polisher does not snag and throw it across the shop) and polish the heck out of it at least through grade C, then use that as your standard for comparison. Final polish with grade S seems to work well with lighter forces and can be done after assembly, and is what you will want to do yearly to keep it polished.
Once you have done some polishing in the flat, you will find it is so easy, that, while others admire your finish, you feel sorry for, and admire the skill of, folks who go to great lengths to get a really good paint job.
I used Nuvite pads with low cost conventional polisher for grades F and C, starting each application at lowest speed to spread smear of compound, then increasing speed as compound was worked in. Finished with Cyclo polisher for grade S.
David A. Sonex TD #1327, lazy man's polish, (painted undersides wing and tail, and all hard to keep polished moving control surfaces.)