Plating Question
 

I recently had some parts zinc plated and when I got them back they were VERY shiny--they almost looked like they had been chromed. I had expected a much duller, grayish appearing finish. When I questioned the plater he stated that when new my parts would have appeared the same way, but had become dull and gray from almost 40 years in the engine compartment. Should I believe him? If he is correct, how can I get the shiny new appearance toned down so that it looks more original? Thanks!

Re: Plating Question
 

Are you sure your parts were originally zinc plated and not cad plated? Cad is much duller, and is what was originally used on coil brackets, alternator fans, etc. When zinc was used, it tended to be a dull zinc, not a bright shiny zinc like you see in hardware store bolts. I'm speaking only re: GM cars. Ford and Mopar may be different.

Re: Plating Question
 

Kevin
I feel your pain, I personnally do not like Zink plating. On all the cars I have done I am lucky to still get white and yellow Cad done here in Akron at Berringer Plating. Man they do a great job for me, but I really prep well for them.
This first picture of the Booster and MC cover is Zink. Notice the shine. This was done by Steve Gregori in CA. Great job he does by the way.

http://i18.photobucket.com/albums/b1...ke/copo228.jpg

These next shots are Cad I had done on the last car.

http://i18.photobucket.com/albums/b1...ke/copo229.jpg

http://i18.photobucket.com/albums/b1...ke/copo227.jpg

You can tell the finish is not as shiney. The Cad coating is far better for corrosion protection too.

Hope this helped
Mike A

Re: Plating Question
 

http://img.photobucket.com/albums/v4...s/image032.jpg

Re: Plating Question
 

I take boosters apart and have them plated and the inside of the booster that has the original plating still looks shiney just like the parts mike is showing, and they are 30 years old.

Re: Plating Question
 

Had a feelong Chuck would chime in here !

Re: Plating Question
 

Zinc is so fragile and the cadmium is so much more durable, I'd do the cad in a heart-beat. If you could see Mike's (M22Mike) work, you'd go with the cad. Just my $.02 worth.

I have also had Beringer's do some black-cad plating for bolts/brackets and the results are very good.

Phil Woj.

Re: Plating Question
 

Thanks for all your opinions on my plating question. The part I am referring to is a bracket that holds the anti-dieseling solenoid. I have a copy of the original GM blueprints for the part and they very clearly spec "zinc" plating for the bracket. The original plating sure does look like cadmium though.

Re: Plating Question
 

Mike,
Your parts look great!
Can you share just what is involved in your "prep work" that gives those results?
thanks,

Re: Plating Question
 

Aluminum oxide blast, acid etch with phosfuric acid such as "Ospho" brand. DO NOT use Muratic acid, it is real nasty. Rinse in close to boiling water with some backing soda mixed in Then blow dry with shop air or a heat gun on a terry towell. Rinsing in really hot water gets the stuff dry real fast and keeps the flash rust to a minimum. And keep in mind the plater is going to re clean again but the nicer he gets the stuff the better off your job will come out, there not into doing your detail work.
I will also wire brush alot of the stuff that shows, such as Intake bolts and other bright hardware. It just smooths out the effects of the blast process.
Also on larger brackets and sheetmetal stuff I will use scotchbright wheels in a die grinder to polish up the parts.
Just keep in mind any defects or scratches you can see in the base metal will show up through the plating.
Then bag the stuff in good zip lock bags.

More and more on the new bright Zinc plated junk hardware I buy, I have been stripping the zink off the blots in acid and sending them to the plater for Cad as well. Some of the new Zinc plating starts getting fuzzy as soon as you touch it.

Mike A

Re: Plating Question
 

Kevin, The plating looks great.

I have a question re the 69 camaro front park light housings. Can you describe the process of removing the socket and pigtail wire harness to allow zinc plating the metal housing. I would appreciate any advice.

Thanks,
Jim

Re: Plating Question
 

It was my plating, and the process is do not remove anything. The plating is a cold process and will not harm plastic ,rubber, wiring etc.
If you wish to keep plating off the outside of the copper lamp sockets you must mask with a liquid mask. My plater showed me the stuff they use in a gallon can, and I sure do not remember what it was.
But what I used that worked well was a aerosol ruberized tool handle spray I got at the Box Depot store. I think it is made by Dip It ????
Anyway mask the wire lead and housing, then spray 4 to 5 light coats and cure with a heat gun. Score the edge with a Exacto Knife and carefully remove the tape, now your ready to plate, and don't worry about the contacts inside the light socket,the light plating won't hurt anything.
I also did some rear license plate lights and front 69 Nova and 66 Chevelle turn lamps, they came out awsome
Mike

Re: Plating Question
 

I think a little summary is in order here as there appears to be some confusion in terminology and finishes.

Zinc plating can appear dull to shiny, rough to smooth - depends on the surface finish of the part AND plating time and current.

Cadmium plating (Cad) is applied OVER the Zinc base. There is YELLOW cad (most brake boosters) and WHITE cad (Zinc appearance). As mentioned, Cad is applied to increase durability of the Zinc. Polish the zinc plated part before cad and you'll have shiny cad. Bead blast or wire wheel and you'll have a more subdued cad. Etc.

You can finish the part to appear virtually the same with Zinc alone or with the addition of Cad. Plating time and current does affect finish as well. I do my own zinc plating and use "copycad" from Caswell. Some photos are on my website. Real Cadmium is nasty and is not something a home shop wants to mess with.......

Dave

Re: Plating Question
 

[ QUOTE ]

Cadmium plating (Cad) is applied OVER the Zinc base. There is YELLOW cad (most brake boosters) and WHITE cad (Zinc appearance). As mentioned, Cad is applied to increase durability of the Zinc. Polish the zinc plated part before cad and you'll have shiny cad. Bead blast or wire wheel and you'll have a more subdued cad. Etc.


[/ QUOTE ]

Not many plater's apply Cad over zinc.

I think you are confusing the "YELLOW" Zinc (/or Cad).
Finish TYPE II (ASTM-B633)

Zinc plating with the yellow Tint is obtained via the conversion coating process by post plating treatment with (di)chromate acid. The length of time the item is immersed in the solution creates the color, in addition to the pre plate surface condition prior to plating as you stated. Think of the Yellow zinc (Cad) as a additional layer of protection from crossion and abrasion. (Example: The thick layer of skin on Pudding left in the fridge UNCOVERED!)
These additional treatments are intended to provide some corrosion protection or a better surface finish for additional coatings (Could be CAD?).

I had purchased a caswell set up and could only get smaller parts plated at home. I still prefer to send them out to vendors who are willing to run small batches of zinc.

I work near a plate shop for the NAVY.
To many fumes for TODAY!
https://www.yenko.net/ubbthreads/imag...emlins/eek.gif

Dave is Right Get your tanks set up soon!
Plate on!

Jim