1967 Rallye Wheel Center Cap Ornament Restoration

[John D.]

Re: 1967 Rallye Wheel Center Cap Ornament Restoration

inst the gold hue your trying to replicate just the base in the flashing chroming wearing though after all these years in service?

Look at post #18 from the thread from 2009. it's not called out on the part drawing to have a gold hue in that area...

[Richard M.]

Re: 1967 Rallye Wheel Center Cap Ornament Restoration

Look at post #18 from the thread from 2009. it's not called out on the part drawing to have a gold hue in that area...

John,

Thanks for getting in. I was hoping you would.

I have to admit I'm thoroughly confused, as the consensus of many in that thread was inconclusive. I did read your input on Post#18 (also in text below) and I understand. But if it wasn't called out on the print to have any gold hue, I guess a rhetorical question is how are there so many originals with it as others stated they have seen?

Is this a issue of what the "factory intended" versus what "manufacturing produced"? That is another issue which we've had when having other marques judged, in particular Jaguar. This gets tricky. Maybe this is why the JG says it could be both finishes.

Maybe it is lighter chrome on some original ornaments and some copper showed through. Now that I think more about it, those 20 grooves are very narrow and the chrome may have just been sparse, or was the chrome light on the ridges and we see the copper on them. I think it's been proven that sharp corners are platers worst trouble. I have a set of '57 tail lights that can attest to that.

But as I mentioned before, why would it be lighter chrome just in that center concentric circle area and not the rest of the ornament? (rhetorical again)

I just called my chrome shop to see if the person that stripped these originals could verify copper was used on them and had to be removed. The person that did it is away. Is copper called out on that spec.....(GM 4372-M)?

Thanks,
Rich

The drawing for part number 390175 drawn in January 66 and last revised in November 66 shows no specific gold color callout and has the following comments:

-part number 390175 must appear on the inside surface of this part.

-Chrome plate per GM 4372-M.

-Plate thickness on significant surfaces must meet minimum requirements of specifications.

-Finish must be bright on indicated surfaces equivalent to that obtained by buffing and surface must be free of imperfections.

The area that appears to be gold on known originals is not specified as a surface requiring bright finish on this drawing....so it probably wasn't buffed or held to that appearance spec during regular production in my opinion (and jacks).

material: zinc die cast alloy

hope this helps

john

[Gene M.]

Re: 1967 Rallye Wheel Center Cap Ornament Restoration

You have to understand the details of electro plating of any kind. The metal will deposit on the most readily available surface it comes into contact with. The deeper set areas and negative (inside cavernous) pockets will be least able to attract the metal deposit. There for the recesses and depressed areas will receive the least if any of the electro deposited metal. Today's modern platers will set up for recesses to get coverage in areas of this type. But understand back in the 60's GM was in the business of not wasting even one cent on a manufacturing process if it could be avoided. It has nothing to do with age or a lot of polishing, it was made that way. Poor production plating practice yield chrome of lesser quality coverage thus the goldish hue in the grooves. And yes some were better than others.

[Richard M.]

Re: 1967 Rallye Wheel Center Cap Ornament Restoration

Thanks Gene. I understood some of it before, but I understand more now.

I would still like to know if the spec included copper on the cast parts before chrome. I think it would kelp if we knew that.

Rich

[Bob J.]

Re: 1967 Rallye Wheel Center Cap Ornament Restoration

Thanks Gene. I understood some of it before, but I understand more now.

I would still like to know if the spec included copper on the cast parts before chrome. I think it would kelp if we knew that.

Rich

Rich,
I doubt GM specified copper. I think the gold hue you're seeing is nickel.
Most GM plating is chrome over nickel.
Bob

[John D.]

Re: 1967 Rallye Wheel Center Cap Ornament Restoration

richard

GM Spec 4372M which is still used to this day does call for copper, then nickel, then decorative chromium....

hope this helps

jd

[Leif A.]

Re: 1967 Rallye Wheel Center Cap Ornament Restoration

And, as far as the gold hue on the side of the bowtie on my center caps, it may very well just be a reflection of the gold on the concentric rings. Just a thought.

[Gene M.]

Re: 1967 Rallye Wheel Center Cap Ornament Restoration

And, as far as the gold hue on the side of the bowtie on my center caps, it may very well just be a reflection of the gold on the concentric rings. Just a thought.

Leif, I would tend to agree with you. As the bow tie does stand proud of the adjacent rings and should attract the electroplating pretty well.

[Richard M.]

Re: 1967 Rallye Wheel Center Cap Ornament Restoration

richard

GM Spec 4372M which is still used to this day does call for copper, then nickel, then decorative chromium....

hope this helps

jd

Thanks John, Hmmm, that's interesting. Okay, so that could explain it. Keith mentioned way back about that as a possibility, that the copper could show through.

So maybe some had it, some didn't just like the JG describes.

Since I'm a "restorer", I tried to emulate what I thought was the thing to do. I suppose I ended up replicating a possible "manufacturing flaw" in these ornaments, or some age effects. If so, I think I'll just leave them as is.

Quite frankly, I think the light slight gold hue looks better than plain old chrome anyways.... especially on a Black Car.

Thanks for all of the interest in these little details.

Rich

[Keith B.]

Re: 1967 Rallye Wheel Center Cap Ornament Restoration

I only came to that conclusion knowing when GM had parts chromed they did It as cheaply as they could. When you do that some things get compromised and that would be a very thin layer of the top chrome. So there for after 50 years of people washing and polshing thin spots would develop in areas. I could be wrong. As I am not old enough to remember these cars when they were new