I picked up an epoxy SUP for cheap from a buddy awhile back. At the time, I didn't have a spot in the garage for it, so it lived on my surf rack for about a month (or more).
In that time the bottom got pretty sun damaged.
Fast forward to now, I'm fixing a bunch of dings and cracks on the board, and figured it'd be a good time to sand down the bottom and reapply a hot coat.
There is a bunch of tiny white "blisters" and of course the edge of the peeling resin.
How much do I need to sand so those don't show on the new hot coat?
I already hit a good portion with some 500 grit (second picture), but do I need to be more aggressive and get rid of the entire original hot/gloss coat?