Polishing and Plating a Thrashed ZIM Russian Base Metal Case

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Positional timing is my favorite watchmaking task, but a close second is metal polishing and finishing. Polishing is an art all its own. I’m not bad at it, but I recently started investing in more equipment and training. With the help of some local friends who work in jewelry repair and metalworking, I’ve started experimenting with new methods to buff up my polishing skills.

For example, here’s an experimental test subject: the case to the Russian ZIM 2602 watch I recently serviced. It looks sad and bedraggled.

This is a base metal case: solid brass with chrome plating. The chrome is tarnished, worn, and flaking, and the brass is scraped and pitted. The back (not shown) is solid stainless steel.

You find cases like this all the time. Nice watches in bad cases sell cheap on eBay, so it would be nice to know how to restore these cases. What can we do with this little fellow?

Removing the Old Chrome Plating

For chrome plated cases, the first task is to remove the chrome plating. If you own a pool, you might have some muriatic acid handy. For some watch cases, the chrome will quickly dissolve when the case is submerged.

But I don’t recommend the acid, which raises all kinds of safety issues. If a case is heavily scratched, the chrome plating will get buffed and polished off during the process of smoothing.

Polishing the Case

Metal polishing and finishing is one of those things that can be picked up reasonably quickly but takes a lifetime to master. I made a lot of mistakes with this case, which looks better in the photos than in real life.

This case was the victim of my mad-scientist approach to polishing. I tried every trick and tool suggested by my friends on this guy. Behold the implements of torture!

When a case is scratched and pitted, you can either add material (such as filling the holes via soldering) or remove material (such as sanding down to the level of the scratch). For this case, I sanded down to smooth the case surface.

I’m already pretty handy with a bench buffer, so I did most of this case with flex-shaft attachments. Many were useless, and some made things much worse, but I learned a lot through these experiments.

And here’s the “finished” version, you might say. I finished it in the Rolex oyster style: the bezel and sides are polished to a mirror shine, and the tops of the lugs have a satin brushed finish.

Here’s another angle.

Although visually striking, this case suffered from many of my more experimental attempts at polishing. Because I was trying out many new methods and tools, far too much material was removed from the case, and the final product lacks the edges and contours of the original.

Alas. Learning isn’t pretty. But that is why this watch case is literally a “test case.”

Electroplating the Case

Once the bezel and case were polished and finished, it was time to replate them. I opted for nickel plating, which is easy, inexpensive, and predictable compared to chrome or rhodium plating.

If you’re curious to try nickel plating, here’s a good guide to it. You can make your own plating solution, but an easy way to get started is to buy some. I used a pure nickel anode and a liquid plating solution from Caswell.

The idea behind electroplating is simple. The positive lead is connected to the nickel anode; the negative lead is attached to the watch case; and both are submerged in the nickel solution.

Nickel plating, like BBQ ribs, is better when done “low and slow.” You’ll get better results if you use a low voltage, keep the anode and case far apart, and submerge a small area of the anode in the solution.

You can see the case bubbling here.

Good electroplating requires an absurd commitment to cleanliness. Any leftover grit, buffing compound, fingerprint oils, or cleaning solution will prevent good adhesion or contaminate the nickel liquid solution. You need to scrub the watch case to within an inch of its life, degrease it, and rinse it in distilled water before plating it.

The watch case might come out dull and tarnished. If so, you should reduce the voltage or increase the space between the anode and case next time. The dull, hazy covering will come off with a quick buffing with a soft cotton buff and red jeweler’s rouge.