Your trying to set a bevel with a 12k!? No wonder you went blue in the face. I wouldn't be using a slurry made from 2k sand paper either, coz you will possibly do some micro chipping with the sandpaper. Slurries are made with the same or higher grit stone. Though nowadays a diamond hone can be used, which speeds things up and avoids cross contamination of lower grit particles.
A bevel
can be set with 1k sandpaper, but I'd recommend you get yourself a 4/8k hone. That is unless you do have nothing but time on your hands and like to try setting bevels with 12k, but I imagine that novelty would soon wear off.
EDIT: OK so Russel said the same thing, but its always good to emphasize stuff.