Dry suits help keep scuba divers and snorkellers alike stay warm in extremely cold water temperatures. By keeping the water from ever touching your body, these suits allow you to stay underwater longer than normal. Unfortunately, a leaky seam can disrupt that system. With suits costing in the thousands of dollars, buying a new suit just because of a leak can be very costly. Have no fear, as you can repair a leaky seam; the new types of tapes and glues have rendered a leak no longer such a big deal.
Identify which seam has a leak. (Either note where water comes in when you wear the suit or check the seams for holes.) Turn your suit inside out. Then, with an erasable marker, circle the seam spot.
Place the seam tape on the seam from the inside of the suit. Use generously, covering every leak.
Seal the tape using the heat gun. It will self-seal when you apply heat.
Fold your dry suit back to outside out. Fold the seam, and check for spots you might have missed with the heat gun.
Hop into the water, and check for leaks. If you don't feel a leak, your job is complete.
Practice with the heat gun before performing the real job. This will prevent accidents.
Applying heat to the wrong area can seriously damage your dry suit; when heating the tape, only heat the tape and not the neoprene/rubber.