Hey smoggy,
Sorry to hear of your problems -- but ,I may have some answers for you !!
Epoxy is one of my favorite products, but thru the years, it has also given me a lot of pain !!
My first question is -- how old was the epoxy paint ??
The stuff has a definite "shelf life", after which, it can give you a lot of problems -- one of the most noticable being -- the damned stuff, will either cure to soon or take forever ... Most of the time, it will take a long time to cure !!
Another thing I think I saw on your parts, was some spots, indicating, contamination !! Perhaps some grease residue, causing a thinning, or "fish eye", on the parts -- I clean, with laquer thinner, or MEK, before painting, but some substances, just don,t want to come off..
One other thing you might try in the future -- use glass beads in your blast cabinet, insted of sand -- they are, just what the name implies -- spherical, round beads !! These clean, without doing damage to the parts -- but use at or below 80PSI, or the beads are shattered into dust !!(NAPA auto parts stores)
As for removeing the magnets -- I think you could put a wood block, against the mags you want to remove and smack it with a hammer -- as you did not imbed them in resin, they should come off real easy !! In fact, most of us imbed them , almost to the top surface, and some, even run a layer of fibreglass cloth over them as they occationally come loose !! (check out Dan B,s rotors)
Going back to the epoxy paint -- I normally paint several thin coats, then put them under my heater, with warm air blowing on them -- go have lunch, and put some more on after the first has cured a bit -- the stuff likes to run !!
I think your problem though, was "old" epoxy !!
Other than that, I didn,t read your post to thoroughly, but I noted your use of aluminum to check for eddy currents -- perhaps I didn,t understand, or thououghly read, but aluminum is not magnetic, so would not react to magnitism !!???
Anyway, I wish you better luck in the future, and hope something I wrote, might help .. Bill H.....