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Removing old concrete/cement from tiles and tools


Alan Zoff
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I have lifted a number of very thick old tiles in our hallway, some having sunk. They are a nice original feature which I wish to retain but I am having difficulty removing the concrete that came up with them and is now firmly bonded to the undersides. I have already broken 2 tiles trying to remove it with chisels, angle grinder, etc and wonder if anyone out there has suggestions. (I would have relaid them with the concrete attached but I have already put in a new level concrete base, leaving just enough for the thickness of the tiles and a mortar bed, so that's not an option.)

While asking this question, it seems appropriate to ask if there is something also which will remove old concrete/cement from metal tools. I have a spade and shovel which were top quality tools but the previous user allowed concrete to set on the tools before cleaning them and it is resisting all attempts to remove it now - the shovel must weigh four times its original weight! I had an idea there was a chemical designed for this job but haven't been able to find it.

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I am also very inteested to know if this is possible!

I am shortly to re-do a shower room and the previous owner, as is common in France, grouted the tiles around the lovely white porcelain basin with cement, not tile grout!

I have a suspicion it will have to be an acid, since cement is basically baked limestone, which is of course, calcium.

Edit: This might assist! http://www.flexco-nz.co.nz/pdfs/organo_cement_emulsion.pdf 

http://www.google.co.uk/search?hl=en&q=Dissolving+hard+Portland+cement&meta=[:D]

 

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[quote user="Alan Zoff"]

While asking this question, it seems appropriate to ask if there is something also which will remove old concrete/cement from metal tools. I have a spade and shovel which were top quality tools but the previous user allowed concrete to set on the tools before cleaning them and it is resisting all attempts to remove it now - the shovel must weigh four times its original weight! I had an idea there was a chemical designed for this job but haven't been able to find it.

[/quote]

 

There are chemicals and gizmos galore in this world that sell hope and deliver dissapointment, one day I will invent a word for all these useless products, they are usually described by the seller as "its brilliant, we sell loads of them" translated as we make loads of money from selling it to soon to be dissapointed customers.

Put the shovel head in a bonfire.

It is what I have to do to the drum of my cement mixer after people have borrowed it and to their mind have returned it clean.

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We used to have a sign in the workshop which read,

          " Sorry! The mechanic who used to lend out our tools was just fired!"

I will only ever lend my kit to a few close and trusted people, these days JR: invariably, it comes back cleaner than it left.

It is possible to dissolve set cement, chemically: either Muriatic (Hydrochloric) or Sulphuric Acid, at about 10%. I am still trying to find out which is best.

 

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I had been reading up on muriatic acid (which apparently is weak hydrochloric acid) and wondering where I could buy it. As far as the tools are concerned, I will give the bonfire trick a try first, and will hope that the handles survive.

The acid may still be the answer for the tiles, if I can find a supplier in suitable quantities. (So far, I've found industrial suppliers and someone selling it in tablet form for medicinal purposes - not something I would choose to swallow.)

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[quote user="J.R."][quote user="Alan Zoff"]

While asking this question, it seems appropriate to ask if there is something also which will remove old concrete/cement from metal tools. I have a spade and shovel which were top quality tools but the previous user allowed concrete to set on the tools before cleaning them and it is resisting all attempts to remove it now - the shovel must weigh four times its original weight! I had an idea there was a chemical designed for this job but haven't been able to find it.

[/quote]

 

There are chemicals and gizmos galore in this world that sell hope and deliver dissapointment, one day I will invent a word for all these useless products, they are usually described by the seller as "its brilliant, we sell loads of them" translated as we make loads of money from selling it to soon to be dissapointed customers.

Put the shovel head in a bonfire.

It is what I have to do to the drum of my cement mixer after people have borrowed it and to their mind have returned it clean.

[/quote]

I quite agree about products which promise the earth and deliver moondust, JR!

A word (I'm always inventing 'em!) that sums up, for me, the combination of ersatz science with modern marketing smultz is "Technography" which means Technological Pornography!

Sadly, far too many mainstream blue chip products are affected: you know, "Try new, improved Silky Scene Soap, with magic ingredient MX 13-40!!!" Adverts are normally screened with pics of desirable female "scientists", (you can tell they're scientists, 'cos they wear white lab coats and have thick framed tortoiseshell glasses and are holding a testtube up to the light and trying - and failing! - to look intelligent!).

There's an ad at present, which shows a geezer extolling the wonders of the new fairly dishwasher tabs.

He places a white china oven dish, encrusted with well baked cottage pie (so he says) and with the addition of one magic tab, the oven dish comes out like new!

Anyone who believes that, has never made cottage pie; unless, of course, loading a foil container of ready-made pie into the oven to warm it counts! [6]

Thus, George, without wishing to look a gifthorse in the mouth or become curmudugeonly, after your kind posting, I think JR and I and possibly a few others, will keep looking for the correct acid which will (guaranteed!) dissolve the baked limestone or if you like Calcium Oxide (see here: http://www.britannica.com/eb/article-76639/cement#609156.hook).

Once the Calcium Oxide is dissolved out or "Reduced" the material should be friable and crumbly.

 

 

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I've cleaned up loads of tools, tiles, bricks etc using a cheap 4 1/2" angle grinder I bought from Screwfix. I haven't broken a single tile yet using this method.

The trick is to take your time, and ensure that the item to be cleaned can't move easily, otherwise it can be flung off by the rotating disc.

Don't press too hard with the disc, use it at as near to 45 degrees as you can, and let the disc do the work.

 

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[quote user="Gluestick"]

Thus, George, without wishing to look a gifthorse in the mouth or become curmudugeonly, after your kind posting, I think JR and I and possibly a few others, will keep looking for the correct acid which will (guaranteed!) dissolve the baked limestone or if you like Calcium Oxide (see here: http://www.britannica.com/eb/article-76639/cement#609156.hook).

[/quote]

No problem, considered something of a cynic myself, it took me a while to remember the name, do a search and was pleased to find it.  I do remember it being recommended to me by contractors, along with warnings about not leaving it near tools.  Eventually they gave me some to try, but don't honestly recall actually using it.  A couple of moves along the way, I've no idea where it went, so obviously can't actually endorse the product. 

Perhaps someone else has tried it? 

 

 

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Thanks for your understanding, Geo! [:D]

Over the years, I have suffered huge disappointments with "Magic" fluid guaranteed to cure all ills and remove all stains! Hang on a mo? [8-)] As Jc says, it's called Snakeoil! [:D]

105E: yes, the small high speed angle grinder is aces: have one too.

However, my prob is cleaning off hard cement from around a lovely white bathroom sink which some idiot (previous French owner!) has grouted in with cement. Around the curves and edges; and not just a little thin line, in places it's half an inch wide! [:@]

If I try and chip it, it's bound to crack the surface of he glaze.

 

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For cleaning up similar things when restoring cars machinerey etc I have used a scotchbrite wheel either mounted on a pigtail shaft on the bench grinder or in the chuck of a diegrinder.

It has certainly removed cement and other accumulated gunk, paint, rust etc from metallic objects for me without (visibly) scratching the metal although I also use it for sateen polishing stainless steel.

I recommend that you give one a try (underneath the sink first) as I know that it will remove the cement and am fairly certain that it is soft enough to not damage ceramic basins or tiles.

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It's a good idea, JR, thanks.

It sound rather pedantic but it really is a lovely basin; white china and a very engaging shape and perfect for our use when this room is updated.

I know that many would simply junk it and fit one of those glass mixing bowls on a stand, instead!

Even my son said, "Dad! Don't you dare get rid of that basin!"

 

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[quote user="Gluestick"]

I know that many would simply junk it and fit one of those glass mixing bowls on a stand, instead!

[/quote]

 

When anyone mentions anything like that I say sternly "the "C" word is interdit in this house" - "what? I didn't swear did I" say they.

To me "contemporary" or "contemporaire" is worse than using the "C" swear word!

Will people really be wanting to keep frosted glass bowls with nowhere for soap etc to rest, supported on sharp edged stainless steel frames in their bathrooms in a few years from now?

And don't get me started on those stupid square edged chrome taps that look like they havn't even been deburred and would make a great lethal weapon, where will it all end? Bedrooms that resemble industrial slaughter houses with polished granite floors?

TV makeover programs have a lot to answer for!

GRRR - Rant over!

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