My actual professional life is the conservation of metals. Where they have been around a few hundred years, but retention of original surface polish and metal working concepts can, after treatment, still be visible.
When I first built my Hugh P's neo magnet 12 footer, I was surprised at the poor condition of the so called new neo magnets. The plating was poor with staining from the original plating bath acids, and poor plating adhesion.
I therefore treated each of the 32 magnets separately, and in total took me about 20 hours.
Using a stiff bristle brush and a soft 8 row brass brush only where corrosion was present.
First, all magnets. Corrosion chemically and physically removed. Stiff Bristle brushed with a rust removal jell, (normally a hydrochloric solution)
Cleaning.
1. All magnets, totally immersed and then bristle brushed in 8 deionised water to 1 Horolene (Concentrate of Ammonia & detergent, sniff it and your on your back) fluid for 18 minutes, this removes any corrosion or oil residues.
2. All parts rinsed with light bristle brushing in Isopropyl Alcohol (a water neutraliser), for 13 minutes, Excess fluid removed with cotton swabs.
3. All parts immersed in fine grit-o-cobs, synthetic absorber.
4. All parts warm air-dried, for a minimum of 20 minutes.
5. All parts soft brushed with French chalk, all parts then soft brushed.
Now the magnets are chemically so clean that even your finger print moisture will mark the magnet and corrosion will start.
This process repeated over and over again until no corrosion present. If you look at metal with a microscope you can see the surface is normally like a sponge, so the more you polish a surface correctly the less likely you will get ingress of moisture etc that then causes corrosion.
Ultrasonic cleaning is not recommended, as at very microscopic levels the metal can be damaged and more metal becomes porous.
I also treated my main magnet discs with the above treatment.
Once treated handle with cotton gloves and assemble as normal, I use Vinyl ester resin, but have stopped using Epoxy resin as this has caused problems where loading takes place, i.e. washers bolts etc, as the epoxy resin just chatters and then moisture can get in.
I have fume cabinets and all safety stuff, but please wear protective gloves and eye protection.
Results 3 years later;- Magnets look okay but staining colour present but no actual corrosion protruding from the magnets. Light Corrosion around the parts where the Epoxy resin has stressed/cracked due to mounting bolts.
My later turbines have the black coated Neo's and i could not find any problems with the coating.