Pocket watches crystal glass scratches removing

Removing scratches from watch glass can be a long and tedious job. But if difficulties don’t scare you, here are some suggested techniques.

The standard approach is to grind the whole surface down to the bottom of the deepest scratch and then do the same process with each successively finer grit of diamond compound. Generally it’s simpler to slightly dome the surface like a shallow cabochon, but if authenticity is important for the value of the watch you should keep a flat crystal flat – which is much harder, requiring a hard lap; it’s like cutting one large facet.
On a positive note, there no need to remove the glass from it’s case bezel, although this took lots of patient care not to mar the metal.

The use of the “Watch Crystal Scratch Repair Kit for Plastic and Glass Crystals” is not effective, according to users. The kit is $25. One person has tried the kit with little success. This is what he said: “I’ve use that same kit purchased from Cas-Ker and was very disappointed. The sanding discs wore through on the first attempt to polish and left the surface wavy. The plastic polishing compound seems to work but I get better results from a buffer charged with a crystal polishing compound. I haven’t yet use the glass polishing system but fear I will get the same results.”

The easiest way is to find one of the “eyeglasses in an hour” stores which has some mighty fancy eyeglass grinders busy grinding away, and ask them to polish the crystal.

If you feel you have the potential to do this work yourself, you’ll need a flat surface on which to put, grit side up, a piece of emery paper of, say, 250 mesh grit. Using a figure-8 motion, grind off the scratches. The crystal will then appear somewhat milky. Carefully clean off any residual grit, set up a 400 mesh paper at a separate location, and polish the milkiness off. There are polishing wheels lubricated with water to do this work, but they cost lots o’ money. One undesirable outcome of the hand method will be that the edge of the crystal face will be a bit rounded unless you rig some way to keep the crystal from tipping randomly as you grind and polish.

For the same purpose, you can use a compound called cerium oxide which is sold by automotive parts houses for the removal of scratches on windshields. It is used in a buffing process after mixing with water. It does work but requires endless hours of polishing. If the crystal gets too hot in the process it can crack. The chemical is also toxic.