How to Replace the Moisture Seal in a Bathtub

Cut the old moisture caulk seal away from the bathtub with a utility knife. Pull the old caulk out of the crevices around the tub and throw it away. Remove any stray threads of caulk left behind.

Pour some mineral spirits onto a rag, and clean the area where the new moisture caulk seal will be applied. Let the cleaned area dry for a few minutes.

Cut off the tip of the tube of silicon caulk at a 45 degree angle with a utility knife. Push the caulking gun's steel pin or a nail into the tip to open the caulk tube. Load the tube into the caulking gun by placing the tip through the hole in the end of the gun opposite the handle. Push the tube end into place until it clicks.

Run a bead of silicon caulk around the bathtub in the crevice between the bathtub and the wall by holding the gun at a 45 degree angle and applying a steady pressure to the handle. Release the caulking gun handle, and pull the gun away quickly when you reach the end of a crevice to prevent stringing or dripping of the caulk.

Tool the moisture caulk seal by running your finger over the caulk, pushing it firmly into crevices to create a tight seal. Let the moisture seal dry overnight.