I need several fans and have found a bunch of good ones with no broken fins, but they are rusty or the paint is worn, some aluminum pitting and are dirty.
I was always told not to take them apart, but I can't see why not as long as I mark them. Most of these engines are getting balanced anyways.

So I'm going to take them apart and PC the pulley half.
Should I PC the fan half? Or is that asking for trouble? Worried about the mounting surface, PC is kind of thick.
I could just blast the aluminum clean and leave it raw.

BTW in my hunt I tossed about two dozen fans on the scrap pile due to broken fins.
Friends don't let friends use screwdrivers on fans.

I powder coat the ring and mask off the groove for the pulley. Keep the bolts as they are 7mm and hard to replace.
I blast the fan them wire wheel to to make it shiny. I would not powder coat it.

That's what I've done in the past, except it was one at a time and usually just rattle can.

Just a point of note, the pulley ring and fan are balanced as an assembly.

Need to mark them to re-clock them properly upon re-assembly. I filed a tiny mark into the pulley ring that still shows up after powder coat. (opposite timing marks & scribed the aluminum fan).

I've powercoated my pulley rings. Lot of folks have powder coated pulley parts (motorcycles, hot rods, etc.). Not really an issues anymore than painting a pully. PC will have more mass than rattle can paint so that is a disadvantage of PC. I'd say any effect of rattle can paint mass changes would be negligible.

I also will have entire rotating mass dynamically balanced before final engine assembly. I'm not worried about PC mass canges to the pulley since they will get balanced out.

Not yet used, so I'll report back someday.

When you get a NOS assembly it is balanced. Comes with fan, bolts, spacer washer and crankshaft hub. I have one still in cosmoline. Try and get some pictures later.