QUOTE(Mikey914 @ Jul 19 2023, 09:38 AM)
Black paint maybe. Black oxide will turn rust. I thought these were cadmium plated.
If it is coated with a wax it could work for that application, but everything else was a cad coat. Not to say they didn't do it, but why?
FWIW - When I was at Luftgekult I had a chance to speak with the person running the technical side of Porsche Classic Restorations from Atlanta. I asked him about the plating used on hardware for 60s and 70s cars. In general, he indicated Zinc was used. Not cad. Clear chromate (silver appearance) for 60s and yellow chromate (gold appearance) for 70s. I asked the question in the vein of what was original, but it is possible he meant that is what is used today when restoring.
This seems consistent with the 356 parts catalogs I have which lists coating for a lot of the parts (e.g. gal zn 12). I've not found similar detail in 914 catalogs or references to cad.
I've done quite a bit of homework on this and realize the plating debates will probably never end. Other than the PCNA discussion, the most definitive discussion I've found is on the
Early 911S Registry forum. Its sounds pretty convincing and applicable to all Porsche’s regardless of model.
With regards to black, in the 356 catalogs there is reference to both black phosphate and black zinc. I don't know if you can tell what is on a part just by looking at it. I will probably err towards zinc as I understand it is more durable.
- gal zn 9 (zinc - black chromate)
- phr e (phosphate, black in appearance)