mkhargrove

Many of the original parts under the are alloy with a yellowish finish of some type applied (sometimes is has a green hue, sometimes you can see a violet hue...when it's new).
I have no clue what that coating is. I don't know if it's electrostatically applied, or if it's just a paint, or what....but it's pretty much halfway gone from just about every piece under my hood, and when I clean up a bracket, or fuel rail, or whatever I can count on ending up with almost none of it left.

I've googled....and I have found nothing about what type of coating it is. I would like to apply it to pieces that I've wire brushed, sanded, etc.

I've found some raw metal coatings on the Eastwood website, but they are all supposedly clear....I prefer to go back to something closer to stock if possible.

Any thougths?

mkhargrove

i think i might have just found it. zinc chromate. i think it's an electroplate.... bummer

Adk46

My understanding is that the original parts were cadmium plated, then given the coloring treatment that makes them yellow, the "zinc chromate" part.

Some go to the trouble of having them re-plated as they were originally. Sources are rare, since cadmium is hazardous. Burbank Plating will do it since it's still specified for aerospace parts. They'll do a bucket of parts for a reasonable fee - but that's the minimum fee (around $200-300 last I knew). Most platers will only do zinc. They don't look different, but cadmium may last longer.

There was a miscommunication, so my bucket of parts ended up colored white instead of yellow. I decided I liked them that way.

Petza914

I believe Greg Brown replates a lot of the underhood parts on his engine builds. He can probably tell us what that finish is (but I believe it's cad plating) and maybe even share a source that does that type of work.

worf928

The OE pieces are zinc (electro)plated. Cadmium plating for mass-market applications stopped in the 70s. The chemical recipe for what was done at the factory is lost to the ages. The modern yellow-chromate on zinc or cad processes do not result in the same longevity. You can make the parts look good, but the ‘yellow’ part of the finish is much softer and more easily damaged than the OE finish.

dr bob

For a lot of those plated parts, there's a reasonable case for adding a layer of clear satin paint over the fresh plating. The pulleys and fan. brackets and such are great candidates. Bolt heads suffer from wrenches so are not the best short of spraying after installation and masking. Good news: It's OK if the clear paint yellows a little as it ages. Just know it isn't fuel- or brakeclean-proof.

I'm thinking about just buying a few buckets of hardware from Mark and dropping them off at Burbank plating. Then pick an area on the car, and start swapping out old for new.

----

A while ago now, Rob Edwards shared a bunch of help and support for my intake refresh project. Part of that was a bucket of yellow zinc chromated hardware for the engine bay. My hardware was good-or-better original, but it still paled next to the bright yellow stuff in the care package. Since I didn't plan to replace everything, I kept the original stuff so it all looks the same. Fast-forward a couple years, and some of the pieces installed on Rob's car were fading to silver color from the bright yellow. Rob has since updated his bits with cad plated pieces, but there's a lesson in here somewhere. Rob lives in a dry and temperature-stable climate area in SoCal, far enough from the ocean that salt vapors don't condense on engine bolts. His GTS is typically stored under a cover in a seldom-disturbed garage several more miles inland. Yet the yellow chromate still did its job, sacrificing itself to keep the rust devils away from the underlying parts.

Rob Edwards

My stroker motor will be 10 years old next May, and I'm less inclined to show the car with the hood open these days, the yellow zinc has faded a great deal. About 10K miles of driving, rained upon maybe once. Hood up after almost every drive to hasten cooling, doesn't matter, the plating still fades.

Minerva's hardware was all done in real yellow cad, with proper prep, to a very high standard by an aerospace-certified shop in Santa Ana. That will be the litmus test for longevity.

karl ruiter

I have my own Zinc plating, yellow 'cad' die setup but I have stopped using it since I don't feel the longevity of the results justify the effort. What I would like now is some high temp rattle can paint in the same color. Seem like it should be possible.

Petza914

The problem with rattle cans, even the ceramic ones, is that it doesn't do well with exposure to petroleum as it reactivates the paint.

I painted some hard fuel lines in my K-Jet setup and when I was working on the fuel distributor of I had any gas in my hands and they came in contact with the lines, the paint would come off immediately, even after full cure time.

When I refinished a fuel distributor I sourced a 2-part paint product - paint with a activator/hardener and that worked great and is super durable.

mkhargrove

you guys are seriously bad to the bone.

Dr. Bob-
Check the Eastwood site....they have a clear metal finish that's supposedly pretty durable and stays clear.....or at least they did at one time.

GregBBRD

Agreed.

There"s no possibility that the German government allowed cad plating by the late '70's. Heck, the cars had to be "electrostatically" painted way before that, to keep paint vapors out of the atmosphere....

Definitely some sort of yellow zinc, on all 928 pieces.


I've found Burbank Plating virtually impossible to do business with. No rhyme or reason to their pricing...not by weight or by anything logical....just whatever mood they are in, when they get it.

mkhargrove

I found this....
https://www.eastwood.com/eastwood-go...SABEgLNpvD_BwE

I assume this is really just to try to get a similar cosmetic appearance....something tells me it's not going to do well with a squirt of throttle body cleaner on it



I just searched for pics....this stuff isn't even close to the real thing. It looks like gold paint.

chart928s4

There is an ambient-cure Cerakote (Glacier series Gold) that I tried as a candidate for a durable coating. I used a brush to put some Glacier Gold on some hose clamps as a test and it looked good but could not sustain wrenching in its thick quick and dirty application. I think someone needs to try an airbrush after full disassembly and tumbling to test it fully.

My avatar intake and cam covers are sprayed with Cerakote Glacier Titanium. It is extemely durable and solvent resistant.

voskian

When I got he 91 GT 7 years ago (24K miles), which had been stored properly for 12 years prior to be buying it, I wanted to preserve the plating and found that WD40 wiped on the plating (usually twice a season) has kept it looking fresh.

The car has seen an additional 26K miles in the last 7 years and the plating still looks good. When Dave C (worf928) and I did the intake refresh on my 91 GT this past spring, we decided to just clean them up and keep it original. All the plated parts were given a good "cleaning" with WD40 and all look great.

Just a data point for anyone trying to keep original plating looking good.

Kiln_Red

Just a clarification..

Electrostatic coatings don't apply to topcoats. The raw unibody and bolt-on exterior panels were e-coated as this process was the best way to apply the first undercoat film. The reason is because no other process will displace 100% moisture and the raw substrate interface will oxidize, unlike the successive coating interfaces.

928s were top coated by hand. Transfer efficiency was less (more overspray) than the robot and more catalyst (isocyanate) was required for the manual spray gun paint jobs = more VOCs / more waste. The quality of the finish was superior for utilizing this methodology, at the expense of the environment.