Who does parkerizing / phosphating ?

[oafpatroll]

So you gunkote yourself? That sounds like an interesting prospect.

Yes. It is but isn't really worth buying for coating a single item as the minimum quantity will do dozens of handguns.

How does that work?

Grit blast and/or chemically etch according to their spec for the substrate, degrease properly, heat parts to their spec, airbrush on extremely light coats, bake to spec. From what you described it's likely that whoever did your 75 FUBAR'd most if not all of the steps.

Where do you buy the paint/finish?

https://www.kal-gard.co.za/coatings/sck-range.html