First attempt at carving aluminum, finishing ideas

Projects
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Last night I made my first attempt at carving aluminum. I had a scrap piece and thought I’d make a 40mm diameter coin. At first it was going to have text, but after lots of warnings I drew a Mickey Mouse head instead. Using the default settings in Easel for a 1/16" bit and aluminum it took about 4 hours, then my right Y belt broke and the bit broke soon after. I assume the belt break caused extra load on the bit because it seemed fine for a long time before that.

2016-03-25 01.21.47.jpg3225×2419 2.18 MB

The surface finish seems pretty good, it looks worse in the photo because the light really enhances the lines. I was wondering what others thought. I was also wondering about any post processing steps to polish it up, do I need to sand, then buff? I’ve also got a rock tumbler and was wondering if anyone has tried a home brew tumbled finish? Someday I’ll take a spare piece and put it in the tumbler with plain old sand and water and see what happens.

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You can reduce that “ripple” effect in the bottom of the pocket by running a larger diameter end mill in the pocket at high rpm, very low feed , and just fuzz the surface (shave off around 0.005" - 0.01") (make sure the endmill is new, or relatively uniform and sharp!)
The slower the feed rate, the cleaner the surface finish.
Gotta say, looks really good!!

-=[ insert thumbs up emoji here ]=-

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Thanks. I didn’t notice until later that the features aren’t as symmetrical as I had drawn them. I tightened all my pulley screws and used Loctite blue. I’ve got some M3 socket screws on order which should be less strippy than the grub screws.