In an emergency you can make a hiking boot water resistant by dripping candle wax onto the welt where the sole joins the upper. But to do the job properly, use boot wax.
Set the boots and the tin of wax in the hot sun until they are warm, or you can warm them with an electric hair dryer. Then apply the wax evenly and rub it in with your bare hands; put an extra-thick application all around the welts. Warm the boots again until the leather has completely absorbed the wax. Repeat the procedure, then remove any excess wax with a dry cloth. If the boots are likely to be exposed to moisture often, reapply boot wax frequently. (A small amount can be carried in a 35mm film canister.)
