I cleaned and refinished some black phosphate hardware recently so I thought I would post some pics in case anyone was curious.
I believe I posted a link to the process earlier in this thread but here it is again just in case.
http://www.southsandia.com/forum/web...e_etching.html
Really super simple. For nuts, bolt, washers etc....I simply put them to a bench grinder with a wire wheel and clean off any rust that may have formed. If the hardware is oily or greasy, then I put the parts in a tumbler with some degreaser and that usually cleans them up pretty good.
In this case, I was working on the rear wheel cylinders. These bolts have a silver cad type finish on 50's and early 60's Chevrolet models but the bolts from my '68 GTO were black oxide finish so I went with that instead. These were wire wheeled on the bench grinder then brushed lightly with a stainless steel brush to clean off any left over residue and then dropped in a small container of Klean-Strip Phosphoric Prep and Etch from Home Depot.
I then left the container in the sun to 'cook' for about half an hour but I lost track of time so it could have been a bit longer. I then removed the bolts and rinsed them very well. I rinsed my parts in a wire basket with a nozzle on the garden hose to make sure I get all the etching chemical rinsed away. Then straight into a quick bath of denatured alcohol and then dry the parts with pressurized air. Then I put them in a small sandwich bag and squirt some WD-40 in there. I leave them in the bag until needed. They can stay in that bag for days, weeks or months until needed.
When I am ready to use the parts, I just wipe off the excess oil and install them as normal. No worry about scratching them with the tools since it's not paint. The parts usually come out pretty nice.
I am not sure why the factory used a variety of different finishes for hardware (silver cad, dichromate conversion, black phosphate etc). I wonder if the black phosphate treatment was used for higher strength hardware or parts where the correct torque spec was more critical. The side benefit of "oil and phosphate" process is the fastener is lightly oiled when put in use so the torque specs might be more accurate. Just a theory of mine.....not sure if it carries any weight or not....
At any rate, here is a pic. One of these little bolts is missing it's lock washer.....broke off during the wire wheel process. I found another lock washer but it's not the same size as the original. This minor detail will bug me until no end so I'll end up searching my hardware stock until I find another one of these with the correct washer and head markings. I am sure that nobody else would ever notice the different washer but these types of things still eat at me anyway. Some sort of disease I guess....
