Author Topic: Chrome 101  (Read 5541 times)

Richard Madison

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Chrome 101
« on: February 23, 2003, 07:13:55 »
Just had the rear chrome on the '71 280 re-done. Thought I would share what I learned.

Triple Plating: I thought this meant that a good chrome job dipped the pieces into the chrome bath 3 times for good protection. No. Triple Plating means that the parts are dipped into three different metals: copper, nickel, and chrome.

First the pieces are cleaned, dents removed, old chrome removed. Blisters are either ground down or if really bad, drilled out and plugs inserted. The cleaned up, smooth piece is then dipped in copper. A good job will leave it in the copper for several hours.
Cheaper shops will cheat here and give a shorter copper bath.

Pieces coming out of copper look weird, imagine a pure copper plated 113 bumper.

At this stage buffing is done. Buffing cannot be done after the next plate is on so after Copper is the last chance for good buffing. After the piece is really nice, it goes into the Nickel bath.

Nickel has a yellow cast to it while Chrome is blue. If you have some old chrome and can see some mottled yellowish stuff showing through that you can't buff out, that's where the chrome has worn off and the Nickel is showing through.

The Nickel bath takes about 30 minutes. All the baths use electrodes and anodes to do the plating with wires connected to each piece. The anode gives up its metal and eventually has to be replaced.  All this stuff is a real bear now with environmental issues, good for the air and water but it has increased costs.

After the Nickel and inspection, comes the Chrome plating. Believe it or not this takes very little time, as little as one minute even less. The chrome is the easy, quick step. Then comes inspection and finishing.

Should last many years, reputable shop will give a lifetime warranty.

Costs vary but will increase if the parts need manual repair such as dents, warts, rust. A small complicated piece like a trunk star can cost more than a larger, smooth piece. I bought a new Star and trunk handle from MB for less than the rechrome charge.

Mine came out real nice and makes a big difference in appearance.
Rear bumper about $175 each; tail light surround $110 each; Trunk mold strips, $65 each. The trunk star and handle estimate $65 each. (MB cost for new Star and Trunk handle is about $35 each.)
These are Philadelphia prices.

Richard M
P.S. If you think a re-chrome for a 113 is expensive: The re-chrome shop was re-plating all the chrome parts on a 1950's fire truck from Long Island. Estimated bill was approaching $75,000.

'71 280 SL, Tobacco Brown, Cognac interior, Tan top, Jump Seat, 80K orig miles, NYC.
« Last Edit: February 23, 2003, 17:29:26 by 280SL71 »
1969 280 SL, Tunis Beige, Euro Model (Italy).

Tom

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Re: Chrome 101
« Reply #1 on: February 23, 2003, 08:03:57 »
Richard,

Nice summary.  So do you have a recommended vendor?  It would be nice to add a section to the site where vendors with whom people have a positive actual experience are listed.

Best,

Tom
« Last Edit: February 23, 2003, 08:04:59 by Tom »
1971 280sl Tunis Beige Metallic

Richard Madison

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Re: Chrome 101
« Reply #2 on: February 23, 2003, 10:27:38 »
Tom:

Suppliers are listed on the LINKS page. The rechrome place I used (Charger Metal) is on the list.

Richard M
1969 280 SL, Tunis Beige, Euro Model (Italy).

Cees Klumper

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Re: Chrome 101
« Reply #3 on: February 23, 2003, 12:18:50 »
Some years ago I had a motorcycle and I decided I wanted a lot of the parts chromed. The shop did all of the wheel spokes (that's a a lot of spokes), several supporting brackets, the air filter housing, the headlight housing, the brake and shift pedals, and several miscellaneous body parts. They did a super job, and all for ..... $25. Those were the days. By the way, the restoration video by Culp Productions has quite anice feature on re-chroming, showing all of the steps outlined by Richard.

Cees

'69 white 280 SL
Cees Klumper
1969 Mercedes 280 SL automatic
1968 Ford Mustang 302 V8
1961 Alfa Romeo Giulietta Sprint Coupe 1600
1962 FIAT 1500S OSCA convertible
1972 Lancia Fulvia Coupe 1.3
1983 Porsche 944 2.5
1990 Ford Bronco II

Longtooth

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Re: Chrome 101
« Reply #4 on: July 24, 2003, 13:32:21 »
The Copper plate layer may be done several times to fill deeper scratches in the metal and/or pitting marks... sanding and polishing between each plating until the scratch(es) or pit marks are filled but remaining surface has uniform thick Cu.  There's also an option of multiple Cu, Ni, Cu, Ni, Cu layers, sanding and polishing after each Cu layer to fill small non-uniformities.  By the way, the reason for the Ni layer is that Chromium doesn't plate well (no molecular attraction) on Cu.  

The difficulty in layering up with Cu (or Cu,Ni layers) is that small sharp details are rounded off.... a good restoration plating shop will have a guy who specializes in detailing with hand tools (no buffers) after each Cu plate to maintain the original sharpness of the features.  The Star on the rear deck is an example.... the points where the star tips enter the surrounding ring should be sharply featured.... and since this is also a current concentration region (acute --- < 90 degrees --- adjoining angles) it's going to plate more in those 'corners' than on the flat sections, therefore radiusing... the obtuse angles (> 90 degrees) are the ones that plate up the least amount.

Longtooth
67 250SL US #113-043-10-002163
95 SL500