I know that the plating of today is a lot different than the plating which was done back in the 60s and 70s. I have seen NOS pieces where the plating was more dull for the "gold cadmium" stuff vs. the shiner stuff of today. I've found a place which can replicate this process and is approved to do this through Fed and EPA as it seems not that many places still do this type of plating due to toxins and carcinogens and such. Is the duller finish for the "gold cad" plated parts correct for OE or factory finish? Or do places like OE "accept" the shinier finish as that is all that is available today?

CAD plating is still available at houses around the country. Generally what you refer to as shiny and dull is refereed to as type I and type II CAD plating. In order to achieve the bright finish plating shops will add brighteners. This is just a visual preference by the OEMs unless they are plating higher KSI steel, usually above 160-170. Materials with high strength are susceptible to hydrogen embrittlement and brighteners add to that effect, This is why you hear people talk about post plating bake (embrittlement releif)

The brightness of a detail is not a result of date, but a result of base material finish and engineering drawing requirement.

I think a good analogy here is an old NOS gas tank that is dull colored compared to a brand new tank that is shiny. The old tank is dull from atmospheric exposure, and the new tank looks shiny, because it is simply not old. Both were made the same way, of terne sheet (steel sheet hot dipped in tin-lead, same as solder). The NOS tank was shiny when new, but it is no longer shiny now.

"I know that the plating of today is a lot different than the plating which was done back in the 60s and 70s." AFAIK, the plating of today is done exactly the same as it was back then, except cadmium is used much less, and the handling and disposal of the hexavalent chromium found in the chromate dips and other bad stuff is done more carefully under better safety regulations.

"I have seen NOS pieces where the plating was more dull for the "gold cadmium" stuff vs. the shiner stuff of today." Although there are wide variations among batches and among vendors due to differing times, temperatures, chemicals, etc., old stuff looks old and dull from long atmospheric exposure. By and large the old stuff was just as shiny back when it was new as todays new stuff.

"Is the duller finish for the "gold cad" plated parts correct for OE or factory finish? Or do places like OE "accept" the shinier finish as that is all that is available today?" I can't say what others accept, but if you are wanting to make a car look brand spanking new and as it was when just delivered from the factory, then your gas tank and your cad or zinc plated parts should look new and shiny. If you want your car to look just like a 40-year old survivor, then the paint and everything else should be slightly dull from 40 years of atmospheric exposure.

Never heard of cadmium cyanide. You might mean chromated cadmium - cadmium plating followed by a dip in yellow rainbow di-chromate? In my limited experience with this topic, I have one original heater valve that is yellow rainbow chromated cad. It is way more eye popping and shiny than anything I have ever seen in yellow rainbow chromated zinc. (However, when I put wax on it, the eye popping luster partly went away.) From this I suspect yellow chromated cad should be quite a bit shinier than yellow chromated zinc, almost spectacularly so.

I hope Mancini does not mind if we admire his car.

I think everything that is silver colored here is zinc plated, not cad plated. (Except the aluminum alternator.)

No yellow rainbow chromate in the photos, only blue chromate.

Blue chromate is put on "clear" zinc and is very subtle, often overlooked. If you look carefully, you can see the hint of blue on the zinc plated stuff at hardware stores.

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Sorry no yellow rainbow chromated zinc or cad in these photos. #8

But you can compare new shiny zinc on this car to the survivor that follows. #9

This is from a survivor car. The zinc is dull from age. The same would be true of cad or yellow cad. A 40-year old NOS part will usually be dull from age too - just maybe not quite this dull, depending on how it was stored. #10

This is the survivor heater valve. Compare it to the '70 Duster.

This is the same part I have that is yellow rainbow chromated cad. Possibly this survivor is cad also - hard to tell. Anyhow, it is old and dull looking, simply because it has not been restored to new condition like it was when delivered new and shiny from the factory.

Cad plating is still available, but I suspect most folks, even the OE contestants, re-plate in zinc and skip the cad.

I can agree that some stuff will oxidize over time. However, stuff that is not in a climate controlled environment will obviously oxidize faster than something that has sat on a shelf in a climate controlled setting. Perfect example would be an NOS part on a shelf vs. a part on a car. Even a part on a car where say that metal clamp that is mounted to the inner fender would have little to no oxidation once you removed it from the fender. The area where it was in contact with the fender should exhibit the same characteristics (color, shine, etc) as it would have been back when it was new. This is also true for the 1/4" return fuel line I found on the keystone clamp on oru 69 GTX. Outside that was exposed to the elements made it look like clear zinc while the part that was "sealed" up to the rubber line showed a gold cad colored part. To me, that would state that the part was originally gold cad and not clear zinc like the outside had shown.

I also agree that there would be different colors, shine, etc as the chemicals were used up and replaced during the process. Same as tint and color of the primer during the body structure when it got dipped in the vats at the factory.

Here is an excerpt taken from the plating service that the place I used had written up about the Cadmium cyanide:

Cadmium Cyanide
Cadmium Cyanide plating offers a unique combination of benefits to many desired automotive components. Cadmium is in its own league with characteristics from corrosion resistance, ductility, solder ability, anti-static and anti-galling. Where dimensional tolerances must be maintained, such as threaded parts, etc. Cadmium can be applied in a very thin layer (plating thickness range of 0.0001 to 0.0002). Type I finished have a natural silver appurtenance, while Type II chromate conversion leaves an iridescent or gold look. Although it was applied during the Muscle Car Era and beyond, this process is no longer offered commercially — only for industry specification contracts and restoration application!

another.

Are your sure the part your looking at is cad ?

Earl,,aka member Snoopy did a test a few years ago on every plated item on his 1970 Cuda and nothing was cad except the antenna retainer under the fender.
Everything else was Zinc. I am NOT saying every model and car line was the exact same plating process. But it brings to question ,,,do your homework.

Also, plated items color and shine can vary greatly from nothing but how long it was in the plating tank. AND the age of the solution in said plating tank



In regards to the fuel line clamps everyone I've seen have been
1/4" - yellow zinc dichromate
5/16" - clear zinc
3/8" - black zinc

Type I, Type II, with or without brighteners, hexavalent vs trivalent chromate, CAD Vs Zinc, base metal finish and prep, strength of bath, dwell in solution (particularly for the chromate conversion coating), and amperage applied during electro deposition. All these items affect the final appearance of the plating.

Survivor or not, the plating will not appear as it was when delivered, but may certainly give you an idea what the original finish was when installed, provided it was sealed against a surface that eliminated moisture or dissimilar metal contact.

I believe you do the best you can to finish the item as best can be determined, actual sheen and depth of color from chromate will vary from lot runs even when Ma MOPAR was ordering parts.

Bill,

So what is the difference between zinc plating and cadmium plating? And would that effect the shine?