This happens to most people eventually. Their Bathtub starts looking bad because the paint is pealing or chipping or maybe there is even some rust starting to form. Eventually all metal products will rust and the paint will fail if you put it in use. Bathtubs don’t see a lot of use continually but over the years with the moisture and cracking of paint the tub will need fixing.
Now the person asking for help wants to save their tub and they say that they are new to do it yourself repairs so they need some good advice.
My personal advice is to forget trying to repair what you have and just install a new tub. The repairs that are available to you are not very good. If you try to paint a tub while it is still in place you will need to use either spray paint or if you go with the best you can a mixed professional paint that just won’t hold up over time.
The best you can get from repainting is when you remove the tub and then have it sand blasted and then coated with a baked on enamel. This is the paint that the tub came with. Unfortunately the action of sandblasting to remove the rust and paint will leave the tub with a textured finish and unless the painter takes this into account you are likely to get back a tub that has a textured finish or maybe one that looks fine in some areas but has that texture in a small spot and they won’t repaint it for free to get it perfect.
The only type of tubs you should consider repainting is a claw foot free standing tub that is an antique. And then you should only consider this if you love the look of antique tubs and are restoring your home. You don’t do this to save money.
If you do want to go through attempting a repaint then you have two options. Purchase a resurfacing paint kit and follow the directions. Normally this means removing all the fixtures and tub drain and sanding the tub smooth with sand paper. Then you etch the pain that remains with a special acid liquid and paint a primer on it then paint their “special paint” on the surface. It will take you a good day or longer if this is your first time painting.
The other option you have is buying sandpaper and sanding the tub smooth and spraying engine enamel and then a clear coat over it. This is about as good as you can get from a spray can and it can be found in the automotive sections of big box stores or any local auto parts store.
However painting it yourself will not last very long so don’t have high hopes. It will look great at first and then about 2 years in if you are lucky it will start cracking and popping and looking like garbage. At that point you can do it all over again because you’re a pro at it.
Honestly replacing the tub with either a new steel or acrylic replacement tub is your best bet. The tub will last you 20 years and look really nice for about half that time.
And if you are going to replace the tub be prepared to replace at least some of the wood floor below it. Your tub may have never overflowed with a child and it may have never leaked but the chances are pretty good some of the floor has rotted.
You should also replace the valves and diverter and up tube for the shower head. Basically this means you are taring out three walls full of tile and the tub and replacing it all.
If I had my choice and the bathroom was over 25 years old and in poor condition I would go with ripping out the walls, replacing the tub and valves and retiling after I installed concrete backer board. It would take a bit longer but it would be done right and it would last longer than I would ever need it to last.