Tub repainting

A. This is not just a matter of simply painting, Barry. Steel/cast iron tubs aren't painted, they are porcelained (a molten frit is sprayed on at thousands of degrees; it's much more like coating with melted glass than paint). I think you might need to hire a bathtub restoration service, not try to do this yourself. They specialize in the many steps necessary to do this reasonably well. Then you would have confidence that the refinishing was a somewhat durable change, not a peeling paint job that will come off in a month. If you attempt to do this yourself to sell the house, you won't know how unsuccessful you were until the angry buyer takes you to court :-(

If you intended to stay a while, then you might try it yourself after doing the necessary prep work. Good luck.

Good luck.

A. Hi Rae. Maybe try a kit offered for the purpose and follow its directions rather than trying to adapt other paints -- but accept that paint will never be porcelain. Good luck.

Regards,

A. Your best bet is to use an Aliphatic Acrylic Urethane and Spray it on. Sherwin Williams makes a POLANE, PPG makes a Pithaine, and Devoe ICI make a Devthane. They are the best. Whatever you do please do yourself a favor and Don't use an epoxy.

A. Normal stripper may work, you are dealing with a different kind of paint here, and a different surface to coat. I think you would be best off letting the people you rent the apartment from replace the tub. But if you are (as I'm guessing) a diehard DIY freak then start sanding. Due to the fact that your tub could be in any number of polymer families I would stay away from any paint stripper, it could conceivably eat a hole in the bottom of your tub. Sand the outer layer of paint off, prime it, paint it. I'm betting that you can't take it outside to paint so I would suggest bringing in more ventilation, some paints give off noxious fumes that will hurt you if you breathe too much of them.

A. Barbara, the thing about old steel tubs is that the finish was not paint (paint is applied with a solvent that evaporates), it's porcelain enamel (which is more like a coating of molten glass). Porcelain enamel is thicker, harder, and far more durable than paint. No paint, no matter how high quality or how skillfully applied, is the equal of porcelain enamel. But porcelain enamel can only be applied in a factory at very high (molten glass) temperatures.

There are services ('bathtub refinishing') who, with their knowledge and good tools, will come in and do a pretty good job of painting it if that approach interests you. Or you can paint it yourself with an bathtub enamel [affil link]. You may find sanding to be more difficult than you think because the porcelain is hard stuff; so thorough cleaning and very light sanding may be more practical.

But it sounds like what you are seeing is not the original porcelain; it sounds like someone already painted it and it's peeling. If you can get that paint off, either with turpentine or sandpaper, it would probably make for a better base.

A. Hi Despina. In addition to the options of having professionals try to paint it, or painting it yourself per the earlier entires in this thread, it is also possible (and perhaps better) to have an 'insert' installed. This is a thin plastic skin custom measured to your tub.

Regards,

A. Hi Rebecca. Try hydrogen peroxide on the stains, as described in letter 8229 before giving up.

Regards,

A. Try a magnet, Greg. If it's magnetic, it's iron/steel. But it's unlikely that the coating is "paint", it's probably vitreous enamel, which is more like melted glass than paint. No paint will approach the performance of such porcelain enamel -- but clean the tub, sand it, and try a paint as described in earlier entries.

A better alternative is probably to call a bathtub refitter. Some use a plastic shell exactly matching the dimensions of your tub, and drop it in and over your existing tub. Obviously, this would cost a lot more than trying to re-paint your own tub though.

A. No dust is good for you, Donna, but I don't know what satisfactory answer people can offer you if the leasing agent doesn't respond. It's not clear whether the dust is porcelain or fiberglass, but I'd bet on the fiberglass. Either way you're not going to pay tens of thousands of dollars to have people enclose the house in a bubble and come in in moonsuits and clean it up with specialty equipment and burn all your bedding as if it was anthrax. So it comes down to the fact that it has to be vacuumed up, and the only question is whether you want to do it, preferably while wearing a paint filter, and using a HEPA vacuum cleaner, or insist that the refinisher have their workers do it :-)

It's probably possible to wash hard surfaces rather than vacuum them, but that probably wouldn't make much difference regarding your exposure.

A. Hi, Cheryll.

Many people have reported easy removal of rust stains on bathtubs with Hydrogen Peroxide [affil link]. I am confident that it's the best thing to try. See letter 8229.

Bath tubs are not painted, they are porcelained (a glass-like powdered frit is melted onto them at a temperature of thousands of degrees). Paint is not likely to stick well, or wear well, but you could try Everbrite [a finishing.com supporting advertiser] clear coat for the dulled shelf areas. This is often used on aluminum siding to restore luster. It works by adding some smoothness to the surface so the reflected light comes back shinier rather than being scattered and diffused. Good luck.

Regards,

A. IMHO: (1) A trained chemist should be able to answer this question rapidly.
(2) Only a trained chemist should be working with highly concentrated hydrofluoric acid. It is dangerous stuff.

Spill some on your skin and the proper treatment is subcutaneous injection of sodium gluconate so that you lose only the tissue and not the bone. I hope if anyone wants to use this stuff they are completely prepared for an adverse outcome.

A. Thanks Tom. I was hoping someone else would say it because I've said it so many times :-)

It MIGHT be okay for professional tub refitters to use this mix if they've been carefully trained in it and they have the right equipment, and if there is no reasonable alternative ... but they should not be trying to formulate it :-(

Regards,

A. That is very scary dangerous stuff.

Wear your PPE. It'll burn holes in you that are very slow to heal.

Maybe just the ABF will do? Much kinder than HF.

A. Hi. Although HF and ABF do much the same thing, the ammonia in ABF is a "buffer" which slows the reaction. The semiconductor industry reportedly uses a range of ratios depending on how aggressive they wish the etching to be. It's very hard for people without experience specifically in porcelain bathtubs to suggest how fast etching you would prefer, or how much is too much, and therefore how much ammonia you should add to slow it down.

You can try commercial products like Armour Etch [←affil. link], XIM Etch-I-M [affil. link], Etchall Etching Cream, & several others, and see which is closest to what you want, and download their MSDS sheets giving their composition. It's probably a faster way to optimize than experimenting. Safe travels.

Regards,

A. Hi Matt
Ammonium bifluoride is used as a SLIGHTLY less hazardous substitute for hydrofluoric acid. I have never seen an application where they are mixed.

The warnings on this thread are SERIOUS. You need PPE and training. There should be a tube of calcium gluconate gel in your pocket at all times - there is not time to go looking for it.

You should seriously consider what happens WHEN NOT IF it goes wrong.

The fact that you have asked this question strongly indicates that you should not be using these chemicals.