Fiberglass repair kits usually include resin and a hardener that, when mixed together, can easily fix a hole in a bathtub and be sanded to create a smooth surface. These kits can be found in a hardware store.
Once the hole has been repaired, refinishing the tub may be necessary to create a consistent texture, color and finish throughout the area. If this is the case, purchase a bathroom refinishing kit along with the repair kit.
After thoroughly cleaning and sanding the tub, paint or spray on the finishing material. Alternatively, many bathtub resurfacing or reglazing companies will provide a free estimate for their services if professional help is needed.
If the tub is made of a material other than fiberglass — such as porcelain or cast iron — but the hole or crack is small and thin, a repair kit may still work to fill in the hole and blend with the original material. If the hole is too big to be repaired with a fiberglass repair kit, or if water continues to leak through the hole even after a repair, the tub may have to be replaced.