Making sure that the structure of your watch is intact is vital to protecting the inside from damage from outside factors, such as water. When you take the back off a watch then you should make sure that you replace the watch back correctly when reassembling the watch after replacing a battery, for example. Some watches are equipped with watch backs that simply snap back into place. You must align these correctly and use the correct tool to ensure that this is done properly.
Attach a plastic die piece large enough to support the watch face into the bottom of the watch case press. Attach a die piece slightly smaller than the back of your watch into the top of the watch case press.
Place the watch face down into the watch press. Ensure that the clamps are holding the watch firmly before beginning the work on the watch back.
Line up the rubber sealing gasket in the back of the watch around all of the edges. Close the back of the watch.
Close the watch case press to snap the back of the watch back into place.