I'll tell you my little secret - I have a local professional shop do my clear and gold zinc plating. We have an "arrangement". That "arrangement" includes me providing the shop with clean, bead blasted parts untouched by human hands (I use gloves), a minimum lot size order (75 pieces), no "due by" date (it's usually 4 to 6 weeks, my stuff is fitted in the shop's schedule) and no arguing. There's other "things" in the mix. I operated in bulk to get minimum lot sizes, I did have four cars most of the time, 65 and 66, so I got ahead of myself. Gold zinc was the most difficult to get minimum lot sizes as those years didn't have a lot of that type finish.
Bottom line - real good zinc plating needs techniques that are expensive and dangerous. There are a few members here that I have supplied with zinc plated parts using my method. I've received no complaints.
Jim
My experience is the professional shops over do the zinc chromate finish. The look is way to shinny to match anything done in the 60's. Think production not show car.
As for "real good zinc plating needs techniques that are expensive and dangerous" I beg to differ.
The technique is the same, its basic chemistry. I knew nothing about it when I started. I did the research and followed the instructions to the letter.
Temperature, constant voltage and the correct amperage are crucial to success. I handle my part with bare hands all the time because the very first step is time in the heated degreaser prior to being plated. Once they pass the "water test" they are good to go. I have done both yellow and black chromate. I had no need for the olive drab green, but the process is similar.
I will start a new thread later in the week. Please be patient as Q4 is my busy time and I am stretched thin these days, customers come first.
Chris