Sounds like you've gone in too Heavy with that grit to me
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Best done by the Pro's with all the tools and materials (and know how) in house if you want a top job I'm afraid...shop around for best price is my advice...a very labour intensive process (even when you're used to doing it) to get 100% mirror if you've ever seen it done
If all fails (i.e you mess up) another option is to powder coat...then you DO want a rough surface to adhere the coating to