Put on your protective clothing, gloves and mask.
Examine the shower pan for leaks. Locate the section that is leaking.
Use the utility knife to carve out a "V"-shaped notch in the crack in the shower pan: You want the crack to be able to hold the filler, so you will need to shape it. Take the utility knife and place it to the right or left of the crack. Hold it at 45 degree angle and push the knife in toward the middle of the crack. You will shave a little of the shower pan off and shape the side of the crack into a slant. Do this for the other side. The top of the crack should be 1/16" to 3/16" wide when you are done.
Wipe the crack with a paper towel.
Sand the area lightly with fine-grit sandpaper and wipe again with the paper towel.
Clean with acetone and a soft cloth.
Mix the epoxy resin or the fiberglass paste together according to the instructions on the packaging.
Apply an even, thin coat to the crack. You will need to work fast, as most solutions start to harden in two minutes.
Apply epoxy hardener if you are using the epoxy resin.
Let the area dry about an hour. You can use a hairdryer to speed the hardening process.
Lightly sand the area to blend with the surrounding surface. If you're using the fiberglass paste repair kit, apply the supplied rubbing compound with a soft cloth.
