Remove tile cement from enamelled bath

[Wesley]

Is there any easy non-destructive way to remove tile cement from a cast iron enamelled bath?

I've ruled out hammer and chisel and angle grinder :-)

[the_constructor]

Now this is something I have had experience of on the past. What I did was to get a rag and soak it in boiling water and then cover cement with rag and leave for about an hour, then using a piece of plastic, old door trim is great for this, just work from the edges until it is removed. It's a slow process and you may have to do it time and time again until it is removed but worth the effort. Jim G

[Andrew Gabriel]

... will wreck the enamel glaze/finish.

Even very weak acids will wreck it.

[Gib Bogle]

This reminds me of a question I have - how to remove tile cement from ceramic tiles? Some of it chips off reasonably easily, but most is very stubborn and with a hammer and chisel there is a real risk of breaking the tile.

[dennis]

Is it water proof or does it soften if you leave it wet for a few days?

[Andrew Mawson]

The glaze on tiles is very close to glass, you can leave brick acid in a glass bottle for years with no harmful effects. Brick acid is hydrochloric acid - same stuff in your stomach. If it takes glaze off tiles then they are particularly dodgy tiles. Glazed tiles are used to line the VATs in some acid production plants

AWEM

[Andrew Gabriel]

Ceramic tiles vary, but if they have a good glaze or a completely non-porous finish, then an acid will attack the cement bond. However, tile cement is not just cement - it also contains glues as a bonding agent, and may contain waterproofers too. So it may be a case of going slowly - dissolving the outer cement layer, and then rubbing the sand free of the glue, before getting to the next cement layer.

If these tiles are fitted in-place, you need to be careful of the grout, which in some cases will dissolve faster than the tile cement in the presence of acids.

Test any acid on one tile first, including cleaning it off and allowing it to dry. If the cement has not been there long, you may find you can get it off with quite weak acids such as vinegar or descaler, rather than brick acid. It sets significantly harder over time. Modern tile adhesives are _very_ much stronger than older ones, which were often little more than fine sand and cement.

[Andrew Gabriel]

Vitreous Enamel looks indestructuable like glass, but it's not. Hence the great care needed in selecting cleaning agents for it. It's very easy to take the glaze/finish off it by dissolving out some of the alkali components with acid cleaners and descalers. This will only damage the surface, but once that's happened, it's slightly absorbent and more likely to get dirt/stains on it, and the shine is gone, so it won't look new anymore.

[Martin Brown]

Apart from preferring a sharpened tooth brush for this I am inclined to agree that weakening it slightly by thermal cycling followed by gentle mechanical removal at the edges is the least worst option.

A very steady hand and a sharp wood chisel might be faster but with greatly increased risk of collateral damage.

[the_constructor]

Drop your tiles into boiling water and leave to go cold. Adhesive will come off easily Jim G

[John Rumm]

Soak it, for a good long time, then attack with one of those stainless scourer thingies that look like a handful of swarf.

[The Natural Philosopher]

mm. Of its vitreous enamelled cats iron, any acid will eventually do it

- i'd start with a de-scaler first and only go to hydrochloric as a last resort.

remove the bulk with a careful scraping as far as you can.

[The Natural Philosopher]

No it wont.

No they wont. Not it its vitreous coated.

Or descalers would ruin baths every day.

[Gib Bogle]

This isn't really feasible - these are 50cmx50cm tiles. I could pour boiling water over them.

[geoff]

In message , Andrew Mawson writes

It depends on the glaze - I buggered the enamel of a bath some years ago with HCl

[Andrew Gabriel]

I don't know what the effect of oxalic acid directly on vitreous enamel is going to be, but an interesting question is what's the stain in/on?

I rather doubt you'd get a rust stain on the polished surface of enamel in good condition which didn't wipe off with vitreous enamel-safe cleaners. That leaves a couple of possibilities; the surface has already been damaged by acid making it slightly porous, and the rust is in that, or there's some surface contamination (such as hard water scale, soap scum, etc) and the stain is in that. In the first case, the surface finish is already gone, and using acids probably won't make it worse (although I don't know about oxalic acid specifically). In the second case, you need to remove the surface contamination. In some cases (soap scum), this is easy with a vitreous enamel-safe cleaner. In other cases (hard water), it's really difficult as the chemicals which most effectively remove it also damage the enamel finish. This is why vitreous enamel baths come with dire warnings about avoiding dripping taps, etc. There's some advice on the Vitreous Enamel Association's website