Working on aluminum tear drop trailers, vintage cast items and epoxy counter tops, I've found some things work, some don't. This is the bar top I maintain
https://mountainhouseestate.com/mend...ery/#iLightbox[gallery_image_4]/14
Take a look at
www.perfectpolish.com. There's video there to help understand the techniques they use. You can accomplish the polished surface without the Cyclo polisher, but they are worth the investment if doing large trailers or airplanes.
I have found that using a random orbital (DA) sander will cause problems, no matter what how fine the grit. The circular micro scratches a DA leaves will not allow the polished surface to reflect the light as desired. This is remedied by simply using a sander that sands in a linear direction. This problem was more pronounced on the epoxy and cast aluminum than 5052 aluminum sheet.
After getting it sanded, you change to different grits of polish, using the advice of your favorite brands. I've used multiple, and they all work about the same in the end.
To get perfectly aligned linear scratches a friend of mine used an Eastwood Contour SCT
https://www.eastwood.com/eastwood-contour-sct.html on his mini teardrop that he pulls behind his motorcycle. You go one direction only, and have to keep it all perfectly parallel to have it look right in the end. I plan on using a device like this next time I polish out the bar tops.
Personally, I'd recommend Kent's solution, as it's repairable.