This is a follow up to an answer someone gave you concerning purchasing product to reglaze your tub.
Even most warehouses for plumbers will not carry the reglazing material. Plumbers do not reglaze. It is a specialized procedure. Very detailed, mistakes can happen at the blink of an eye, then you have a mess.
Also, doing it yourself can cause you potential health problems, unless you utilize safety procedures, such as a resperator.
Do yourself a favor an seek out a qualified applicator.