A common problem with bathtubs is for a hole to develop. This hole can be almost anywhere in your bathtub, but it is not difficult to fix. With a few basic tools, you should be able to fix your bathtub hole quickly.
Determine how large your hole is. If the hole is larger than 3 inches by 3 inches, it will be difficult to patch, and you should consider replacing the tub. However, if your hole is still manageable, you can begin by applying the body filler over the entire hole.
Leave the body filler to cure for anywhere from six to twelve hours, depending on the size of the hole.
Go back and file over the hole with sand paper to make it feel like a natural part of your bathtub. After sanding and removing all excess automotive body filler, paint the entire patch with a color that matches your bathtub. Use a tub and tile refinishing paint or use a fiberglass paint. Your bathtub should look as good as new in as little as seven hours of your spare time.