Josh and Mark

Case Refinishing

April 12, 2019

For the aspiring horological pugilist, there’s always some wicked-sweet fight going on about whether or not to have your watch polished. I mean, people are pulling the knives out over this on sites like Hodinkee. Buckets of digital blood have already been spilled.

At JB Hudson, we like to think of ourselves as a full-service operation. If you have the time and the wherewithal to double-park your Bentley in the cycling lane on 9th Street, the least I can do is hear you out if you want your vintage Vacheron minute repeater “shined.” I serve at the client’s pleasure, and the value judgments obtaining within the collector’s province are not for me to denigrate or enforce. As a mere technician, I profess neutrality and anything else only under duress.

However! I can describe what actually happens during the refinishing of a watch case. After a short course in case polishing basics, you’ll be much better armed for the next on-line scrimmage. More importantly, there will be no need to shirk those difficult decisions before having your own collection attended to.

The Ugly Truth

Not everyone is prepared to embrace the cold facts: case refinishing is a basically destructive process. This is because when we polish a case, all of the various media and compounds are abrasives that do one thing: remove material. A polished watch case is technically smaller and verifiably lighter than before the refinishing was undertaken. I don’t remove the scratch; I remove the metal around it. And if it’s a deep gouge, I might have to remove PLENTY. The acme of true case artistry is to remove as little metal as possible.

That yellow gold President you inherited from your grandfather? The more aggressively it’s polished, the less gold you will have. The money you lost has been converted into a slurry of precious metals, wax, and abrasive compounds that will linger in my air filtration media until I go to the refiner to harvest it. More for me – less for you. It’s not a bad racket, all things considered.

The industry employs a regular pharmacopeia of abrasive compounds to charge any one of dozens of polishing carriers, usually some kind of rapidly spinning wheel of cotton, wool, or rubber. Even the more refined techniques like burnishing or flat lapping – techniques that attempt to move metal rather than remove it – still result in a net transfer of case material to the polishing tool.

It Gets Worse

“Fine!” you might be thinking. “I don’t need some crazy intervention on my watch. Just do a ‘light polish’ and I’ll be on my way.” Not so fast. Consider the modern watch case as currently executed. Your average Omega, IWC, or Hublot has more planes, angles, and facets than a museum designed by Frank Gehry.

What we think of as the more “non-intrusive” polishing techniques all involve the use of large, soft cotton wheels called “buffs.” A soft polishing buff won’t cause the lugs on your Big Bang to outright disappear, but as the cloth accommodates and “wraps” around the angles and vertices of your case geometry, it tends to soften every sharp edge it touches. The most distinctive features of the modern watch case are extra-vulnerable to a “light polish.”.

If we try to compensate through the use of a harder “felt” wheel, there are other problems. While they don’t soften sharp edges out of hand, these media cut aggressively and can rapidly alter the overall contour of a watch case – especially with flat planes like what we see on the flanks of the case, or on a lapped bezel. And once that metal has been removed, it’s almost impossible to replace in the same shape.

The Right Way and the Wrong Way

Don’t despair! There are appropriate refinishing techniques that can be employed by any competent watchmaker to improve the general appearance of your piece. Performed correctly, they do a minimum amount of harm while beautifying an already precious object. Let’s construct a brief primer on what constitutes good refinishing practice.

  1. Respect the Manufacturer: Any case refinishing should seek to comply with the original features and finish of the case. Things as subtle as attempting to fully remove a satin finish, or to apply a satin finish from the wrong direction, can have practical effects on case durability and water resistance. Be conservative!
  2. Dismantle the Case: Polishing done right relies on access to surfaces and angles of attack that are obscured by other components when the case is fully assembled. The esoteric coatings on watch crystals, if the crystals are not removed, are vulnerable to accidental contact with a buff or felt. Most importantly, polishing a fully assembled case can melt gaskets or displace the oils lubricating the movement. Don’t turn your “light polish” into an overhaul! When it’s time to reassemble the case, be sure to include fresh gaskets and the full suite of manufacturer-mandated pressure testing.
  3. Use Manufacturer-Recommended Equipment: The hacks and botchers among us are anxious to employ abrasives that are too aggressive with media that are much too hard. This hastens the work but tends to destroy sharp edges, regular planes, and fragile features like engraving or plating. It’s important to have access to equipment that can rotate at the correct speed. In addition, many cases have features created by a lapping wheel or belt sander, and nothing else can properly address these surfaces.
  4. Respect What You Can’t Change: If the incisor of your barroom nemesis leaves a millimeter-deep notch in the bezel of your Panerai Luminor, you are faced with a decision – and I mean the decision you make after you resolve to quit brawling at Applebee’s. Attempting to polish-out a divot that size might sound like a good idea, but will result in the essential destruction of the part. Replacing the bezel gives a perfect appearance, but at great expense. Better to reconcile yourself to a minor improvement and move on. The truly skilled case polisher knows when enough is enough, and that nothing is perfect.

Good News

In the recent past, a serious knock on a bezel or lug might be enough to force consideration of a full case replacement. Fortunately, we live in an age of wonders and the industry has begun to embrace the use of laser welding to fill holes and restore contours on contemporary cases.

While this takes a more specialized level of training than some watchmakers possess, the major brands have begun to make welding wire available in alloys compatible to the watch cases they sell. Barring other options, it is even practical to reduce the diameter of a spare link screw (if it came with the watch) to produce the wire necessary for minor repairs.