To reglaze a bathtub, take out the trim plumbing, caulking and grout from the tub, ensure that the area is well ventilated, clean the bathtub thoroughly, and apply a body filler in the tub. Then, prime the bathtub, apply glaze over it, and apply caulk and grout on the borders of the tub.
Begin reglazing a bathtub by ensuring that the drains and plumbing around it are functional. If required, make any repairs before reglazing. Then, remove all items kept in the bathroom, take out the spout, overflow cap and shower head, and remove the grout and caulk on the borders of the tub. Also, open all the bathroom windows, and switch on the ventilation fans.
Now, clean the bathtub using an industrial cleaner, and sand its surface using a sandpaper of 120 grit to remove deposits of calcium and paint. Then, rinse the bathtub with cold water, and blow dry using a compressor. Clean the tub with hydrochloric acid, leave it so for about 10 to 15 minutes, and rinse, sand and dry the tub as before.
Next, fill body filler in the tub's bottom and ledges, and sand to smooth the surface. Prime the bathtub using an epoxy material as per the manufacturer's directions.
Cover the floor and borders of the bathtub with masking tape, spray glaze on the tub as per the manufacturer's instructions, and dry the glaze for 24 hours. After reapplying caulk and grout on the borders of the tub, replace the items in the bathroom. Use the tub only after 48 hours.