Anyone ever re-enameled a bathtub?

[Eireann]

Now, you're probably thinking, why ask this question?

It just so happens that I damaged the bathtub by using rather radical methods to clean it. I thought that the bathtub had hard-water deposits on it; looking back, I think it was just ordinary wear from an old tub.

Tip: Don't use straight vinegar to clean an old tub.

Now, I have a tub that's scratched on the bottom and where other parts of the enamel have been damaged due to my efforts. I must say, I did a pretty thorough job.

So, has anyone out there tackled the job of re-enameling a tub, and if so, how did it work for you? Any tips?

[wolfie]

What kind of tub is it (cast iron, stamped sheet steel, fibreglass, thermoplastic, etc.)? For the first 2, the original enamel is actually enamel (baked on). This is the most durable finish available. Fibreglass uses a gel-coat finish, while with thermoplastic (ABS, acrylic, some others), it's the actual plastic.

The "re-enamel" kits you can buy are actually an epoxy paint, which is less durable than baked enamel (i.e. risk of scratching). They'd be the way to go for metal tubs. For fibreglass, I'd go with gel-coat (go to a major plastics supply place - if they don't have it, they can tell you where to get it) because that's what the original is. Get a waxed gel-coat (waxed is for when the finished surface is exposed to air during cure, unwaxed is for when it's against a mold), and be sure to clean the surface thouroughly (get the plastic place to tell you the proper procedure for cleaning old gel-coat before applying new). For thermoplastic, I don't know.

[Imprl59]

I tried it before I redid my bathroom. If it's just one clean person using it then it's decent but if you have kids or tend to get really dirty (I work on old cars) then forget it and just replace the tub. The end result is no where near as good as the original enamel was.

[tropicsgoddess]

When SO and I (along with MIL and her BF) moved into our new house, we got this tub resurfacing kit from home depot to re-enamel our tub (it was this salmon pink color from the 60's or late 50's) white. It's a ton of prepwork and takes a while but it's worth it! It was around 50 bucks for te tub resurfacing kit.

[Eireann]

This tub is an old one, so I doubt very much that it's fiberglass. My guess would be, either iron or steel. It looks as if it may have been re-enameled in the past, or maybe it's just clumsy enameling from the manufacturer. There are some gray areas along the sides near the bottom, which I suspect are caused by the metal showing through.

Pain in the butt. It wasn't broken, but I tried to fix it. Now, I REALLY have to fix it!

[Mikkel]

This tub is an old one, so I doubt very much that it's fiberglass. My guess would be, either iron or steel. It looks as if it may have been re-enameled in the past, or maybe it's just clumsy enameling from the manufacturer. There are some gray areas along the sides near the bottom, which I suspect are caused by the metal showing through.

Pain in the butt. It wasn't broken, but I tried to fix it. Now, I REALLY have to fix it!

You know what they say, if it ain't broke...
If the tub ring when you knock on it, it's metal. It sound like it has been repaired before. As others have said, the repair won't be as strong as the rest, that's why it came off. Vinegar shouldn't hurt enamel, it was probably loose already.

[Eireann]

Well, the vinegar definitely damaged it, so I don't know what the hell it is. This tub is probably decades old, and as I mentioned before, it looks like some metal is showing through. I just want to get it fixed before the owners of the house see it.

[Mikkel]

Well, the vinegar definitely damaged it, so I don't know what the hell it is. This tub is probably decades old, and as I mentioned before, it looks like some metal is showing through. I just want to get it fixed before the owners of the house see it.

I found this. If it's just small scratches, you can probably manage with the touch-up stick. I admit that I have never tried it, but it can't be much different than mending scratches on a bicycle, and that I have tried. If you use spray, make thin layers and let it dry between spraying. It doesn't matter if the first three layers don't cover the damage, it will work out fine. If you use too thick layers, it will drip. If you use a brush, fill the scratches with thin layers of paint and let dry between painting. Stop when the scratches are a bit, just a tenth of a millimetre, higher than the rest and polish it down. If you don't want to do the whole tub, it's very important to match the colour.

Oh, and when using spray, cover everything you don't want painted. You won't believe how far spray paint can float on just a little draft.

[Eireann]

Wow! That might just be it!

Thanks so much, Mikkel!

[Magpie]

Were you using a cleaning vinegar? i.e. the 20-25% kind? Or were you just using plain white vinegar? Because there is no way a 5% acetic acid solution should be able to kill enamel. (Of course, I wouldn't have thought that a 20% would either, but that, at least, is strong). (I am trying to avoid doing the same, and as I definitely have hard water deposits I was considering using some high-strength vinegar).

[Eireann]

No, not cleaning vinegar. I think it was the apple-cider variety. It definitely ate into the surface (which may or may not be real enamel; I don't know), because I can see and feel where it has happened.

[wolfie]

To the best of my knowledge, no nonferrous metals have been used to make bathtubs (at least within the past hundred years or so). Does a magnet stick to it? If so, it's either cast iron or stamped steel, and the factory finish would be enamel. If the magnet doesn't stick, it would be some kind of plastic.

Can you take off the chrome trim at the overflow? If you can, do it, and look to see what happens to the original finish near the actual overflow hole. This would also be an inconspicuous spot for testing.

The grey undercoat may be metal, or it may be the original enamel. I'd advise taking some very fine (400 grit or so) sandpaper and taking a SMALL spot near the overflow hole (that would be completely covered by the chrome trim) down to bare metal (you'd be looking for shiny, not just grey). You'll see the layers of finish going as rings. Try to scratch the grey area (of your test spot) with a mild steel point (dollar store safety pins are great for this). Enamel is harder than mild steel, so if the grey doesn't get scratched, then you know it's been refinished. Also try scratching each of the other rings - if the current finish doesn't scratch, then it's enamel, otherwise it's a refisnish. Enamel is basically a ceramic that's melted onto the metal (which is why you can't refinish with real enamel). It's unlikely to have gone on over a primer coat, instead going on over the bare metal.

Don't try any scratch tests (or sanding) without doing the magnet first - they're for enameled metal only. Try rubbing the test area with a cotton ball dampened in acetone - if it's a gel coat finish, that will come off. Solvent cement (the liquid cement for plastic models) will soften acrylic (acetone might affect it too, since it's from the ketone family, and solvent cements contain ketones, usually MEK). Don't know any paint suitable for bathtubs that is attacked by dilute acetic acid - maybe someone used an alkyd house paint (labelled as "enamel", but not the same thing as a factory finish).

Let me know what the test results are, and I can suggest further action. Note that if an unsuitable paint was used, you're better off cleaning it off completely before refinishing, because the weak point in the bond of the new finish will be the old "refinish" sticking to the original finish.