Many wristwatches show not only time, but also the day of the week and date of the month. While these little numbers are handy, they can be hard to read. Adding a crystal magnifier will enlarge that portion of the watch, making it easier to tell the date and day. You can pay a watch repair person to make this adjustment, or do the job yourself. All you need is the right equipment and a steady hand.
Clean all surfaces that will be bonded. Use a glass polishing cloth to wipe down the surface of your watch and crystal magnifier. Make sure there's no dust or fingerprints.
Place a tiny drop of UV glue on a piece of paper.
Pick up the crystal magnifier with the tweezer and dip the flat side on the glue. All you need is a small dot of glue on the magnifier, an amount about the size of the tip of a ballpoint pen or just a little bit bigger.
Place the crystal magnifier carefully on your watch. Put it on the exact spot where you want the magnifier to rest. You must get this right on the first attempt. Press gently on the magnifier. It's OK to have a little ooze.
Place your watch under the UV lamp for about five minutes. Scrape off any excessive glue with a razor blade.
You can find most, if not all, of the supplies you need in a home improvement store or department store. There are also many options on the Internet. Choose a UV glue tube with a fine tip as is found on brands like Superglue, as opposed to choosing the kind that employs a nail polish-style brush. Crystal magnifiers come in various sizes. Practice with disposable glass beforehand. Test the amount of time it takes for the UV light to dry the glue. Readjust the small hand and big hand of your watch to guide where you want to place the magnifier.
Do not look at the UV light directly. Adding a magnifier to your wristwatch may void its warranty. If in doubt, contact the manufacturer.