: : : My bathroom sink has a crack/indentation in the middle near the drain. I believe it is porcelan or ceramic in nature.: : Without replacing it for now, can I plug up the crack with some type of corking/epoxy that will not disappear immediately from the water and that will seal the crack for now.: go to your local automotive store and get a can of fiberglass repair kit. if the crack is all the way through the sink, apply it to the bottom and the inside. works great on boats…: we have a complete repair kit that you can purchase direct from the factory for $55.00 (includes S/H). Our kit has all the materials and instructions for doing minor repairs and there is enough material to do 10 quarter-sized repairs. Please email or call 800.498.7093 for information or to order a kit. This is exactly what you need to do your sink repair. Our kit is specially designed to work on fiberglass, porcelain, cultured marble and acrylic. Thanks. R. Dale Fussell, President