The crystal of a wristwatch is easily damaged. A small chip or light scratch can usually be buffed out by an experienced jeweller, but if the crystal is cracked or broken, it must be replaced. High-end watches are difficult to open and have safeguards in place to hold the crystal near the casing. A do-it-yourself replacement is not recommended for these models. Many vintage model watches and casual, inexpensive watches have easy-open cases that allow anyone to replace a crystal. This guide offers step-by-step directions to replace a watch crystal.
Buy a replacement crystal. This may be the most difficult part of the replacement process. Look in the local city directory or online for a jewellery supply house. The local jeweller may carry replacement crystals. Bring the watch and the broken crystal, if possible.
Place the watch and tools on a thin towel in a dry, dust-free place.
Light the work area. The interior of the watch may have recessed areas that are difficult to see to do the intricate applications. Use the loupe for magnification.
Wash your hands to ensure hand oil does not damage the watch movement. Dry your hands completely.
Take the appropriate case opener and open the watch case. If the back has a screw opening, carefully unscrew the back.
Do not take out any seals (round, ring-shaped metal or plastic discs) or spacers (metal or plastic frame) at this point.
Examine the interior of the case back for any imprinted directions for removing the movement.
Look for "pushers" next to the watch movement. This is one or two small springs or levers near the watch stem that assist in pushing the movement from the watch. Push on the pusher while lifting the stem. This should remove the movement from the case.
If printed directions and pushers aren't seen, go ahead and carefully remove the seal and spacer.
Examine the stem to determine how it lifts out from the case. The stem will usually lift straight up from the casing, but sometimes it is held in place by indentations on the case. Avoid just pulling on the stem to remove the movement. You may break the stem, especially on a vintage watch.
Place the movement in a clean, dry location where it will not be bumped or dropped.
Remove the old crystal, or remnants of the crystal, from the case with a toothpick. Work slowly and avoid rubbing the exterior case on the face of the watch.
Keep the new crystal clean by using the tweezers to insert the crystal into the watch case. The crystal should fit snugly into the watch case.
Remove the crystal and place an extremely small amount of glue into the ridges that hold the crystal on the watch case.
Replace the crystal.
Allow the glue to dry at least six hours. Overnight drying is best. Cover the watch works with a lint-free cloth, if drying the glue overnight.
Replace the watch movement, seal and spacer.
Replace the watch back.
Use a small amount of Rodico to remove fingerprints from the case of the watch. Follow the directions on the container. When the watch case is open, clean the interior before installing the new crystal. If your watch is an unusual shape or design, the watch crystal may need to be modified to fit the watch. Experiment on a plastic crystal using a small Dremel-type tool with a sanding wheel. Once the shape is perfected, take this prototype to the jeweller or watch supply store to purchase a new glass crystal that best matches the handcrafted shape.
Purchase a case opener. Watch cases have slots, grooves, dimples or round holes allowing entrance to the case. Match the opening on your watch with the case opener. This tool, depending on the type of case and the quality, is priced from £6 to £130, as of 2009. Without the right tool, opening the case can severely damage the side and back of the watch.