How do I refinish a porcelain bath tub? It doesn't clean up well and the finish is rough.

What is the best way to refinish a bathtub? There are several possibilities. You can use a chemical spray or a tub surround and the third option is a custom bathtub liner.this option has a longer warranty.
Answer : Let me paste up a little "how to" I ran across, >> Refinishing old tub messy project for amateur
Q: We are fixing up our bathroom, and the biggest problem is our old tub. Replacing the tub looks to be too big a job, and having it professionally refinished will cost us over $250. Is there a way we can refinish the tub ourselves?

A: You can buy a refinishing kit for about $75, but many people report a high failure rate with these kits. The problem lies in getting a good bond between the new epoxy coating and the old tub finish.

To get the best bond, you must get the bathtub as clean as possible. Although the tub's surface may appear to be smooth and unbroken, it actually has many tiny pores that collect dirt. The pros handle this problem by giving the tub a strong bath with industrial-strength acid. You can, however, get fairly good results by using a very strong solution of TSP (trisodium phosphate) available at paint dealers and home centers.

Follow the directions for mixing a solution at the strength required for removing paint. Wear eye protection and rubber gloves when using this solution.

Clean the tub with TSP solution and a stiff-bristle scrub brush or sponge. Scrub the tub repeatedly - this is the most important step of the job.

If you fail to get the surface clean, the epoxy will peel off. After washing the tub, rinse it with clear water to remove the TSP.

The next step is to sand the surface to break the glaze of the porcelain finish. Use 80-grit wet-dry paper to wet sand the tub.

Again, this must be a complete job - any section left unsanded is a candidate for a peeling finish. The final step is to apply the epoxy. This comes in a resurfacing kit that contains the necessary tools - rollers and brushes - plus the epoxy finish and instructions.

Because professionals use heat to cure their epoxy finishes, they estimate that the new surface will hold up for as long as seven years.

With a careful and complete cleaning and sanding job, you should get at least five years service from a refinished tub before the process has to be repeated.
Or, if you would be interested in relining, click on back and I'll turn you on to a site that sells liners. Hope this helps and thank you for rating my reply. TOM