I used 400 then 800 and finished with a lite sanding of 1200 grit. Bought a set of polishing buffer wheels and bars of polish in a kit off ebay for $92.00 bucks and a cheap polisher from Harbor Freight for $50.00 bucks.
Time to sand roughly 3.5 hrs per tank, time to polish 2 hrs per tank. I have plenty of polish and buffer wheels are in good shape to be able to polish some other things too. Polisher speed 3,500 rpm.
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