Zinc plating - is this "correct"
 

I've been going through my '85 Carrera refreshing suspension and other areas where I can easily unbolt, clean and/or have parts re-plated. I've found a shop locally that can do the zinc plating and is quite cost effective. The results are great for smaller parts in terms of the look, very consistent color without a lot of variation. But for the larger parts doesn't quite duplicate the factory appearance, there is some inconsistency and may be a bit lighter than the original finish. I've been told that my '85 had zinc plated parts, not Cadmium that was used on the earlier cars, although I could not find any information on when that switch was made.

I'm not building a show car, but would like to understand the "authenticity" of what I am doing to the car, and get any opinions on whether the work of my plating shop is acceptable. Photos attached for discussion.

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One more photo of the spring plates before re-plating. I didn't reinstall these on the car as I switched over to the Sway-Away adjustable units.

Bill
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It sure looks nice and correct by the way - could be yellow zinc / zinc chromate.
You can check me but our cars were in fact CAD plated, and while some places may still do it, I believe it was generally stopped due to the toxicity of the process. The yellow zinc is safer and just as nice.

Your color looks great. There is plenty of shade variation on factory finishes and yours fit well in the range. Besides, the suspension parts will get darker due to use in a few thousand miles anyhow...

Only the smallest amount of clear cadmium was used on SWB cars, anything yellow on a 911 has always been yellow zinc.

Thanks, I didn't know that yellow Zinc was the plating all along, feel much better about spending all the time and energy to get as far as I have. Interesting to hear that they will darken up over time as well. If you are in the SF South Bay area Valley Plating in Santa Clara did the work. All of the parts in the photos plus a bunch of smaller bolts, nuts and washers cost $100 with a three day turnaround.

Here's a shot of the suspension before I put it all back in the car. Need to get going on the front end next.

Bill


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We were discussing this here recently in another thread.

Apparently cadmium plating has some environmental concerns but is still used in aerospace where zinc isn't a suitable substitute.

But it's actually the yellow chromate that is used with both yellow zinc and yellow cadmium that is toxic. (Yellow chromate is what gives it the color.) So yellow zinc has some of the same environmental/health concerns. Yellow chromate is nasty stuff. You can buy it from hobby plating supply stores even though it is a known carcinogen.

I think I found the thread you are referring to, plus a couple of others which all had some great information. Looks like this can be done at home, but doesn't appear it's worth the risk if there is a competent shop nearby.

Bill

I tried my hand a zinc plating. (Have not tried the yellow chromate).

It requires a lot of practice and patience. Lot of art as well as science. The investment for the hobbyist is not trivial either. It was fun to attempt but this is one of those things best left to pros.

But on the other hand I have had trouble finding platers who are willing to work on small batch stuff.

That's why I batch things. I've done several orders of just 1 or 2 pieces over the years.

That's one reason I am very happy with Valley Plating. They do a lot of industrial sized jobs, but the guy I deal with is a car guy and said they don't mind dealing with hobbyists. I take plastic bags full of parts in, he holds them up to view and says "that will be $75". They don't loose my parts, and if I ask for them to be kept them separated into the batches/bags I brought in they do that too. Added bonus they are right on my way in to work. I wish they did powder coating...

Bill