Useful Tips

Getting rid of limescale and rust: professional advice

Cement is a unique building material that has no analogues. One of the “products” based on cement is the so-called cement milk, which can be harmful waste in the construction work, as well as a specially prepared mortar for the implementation of various construction and finishing works.

What is cement milk used for?

As already mentioned, this material can be both “useful” and “harmful”, therefore, in order to fully disclose, we consider both concepts. “Cement milk” is a “useful” application in repair and construction practice:

  • As a protection of various concrete structures, primarily concrete platforms (paving, entrances, pouring poles, concrete yards, etc.) and tracks operated outdoors. The so-called "ironing" of concrete,
  • As a protection of the internal surfaces of steel tanks against atmospheric corrosion,
  • As an initial pouring step when using concrete pumps,
  • As a mandatory component in the preparation of the cement part of concrete for pouring light foundations based on granulated slag and expanded clay. Approximate proportions of "cement milk" - 1 part Portland cement M400-M500 in 2 parts of water,

It is worth noting that, since the proportions of “cement milk” are not regulated by any regulatory documents, this issue is solved in each case, “by eye”, based on the experience of a particular master builder.

Milk with cement - “harmful" factors

“Harmful” cement milk is released from concrete or cement mortar immediately after pouring the structure. In this case, it forms a film on the surface of the concrete, which creates an obstacle to the monolithic connection of the base with decorative coatings. And also leads to delamination of the surface layer of concrete.

If the basis of “milk” is an aqueous solution of calcium hydroxide, a water-soluble film of calcium carbonate forms on the surface of the base, which peels off, which leads to the gradual destruction of concrete.

In addition, "cement milk" can be formed as a derivative component of alkali metal salts, sucking in the composition of concrete or cement mortar. In this case, air carbonization of the surface layer also occurs with all the resulting "troubles" for strength and durability. In general, the expected strength of the concrete surface layer is reduced by at least 2 times!

Therefore, in these cases, "cement milk" must be removed in the following ways:

  • The chemical method of removing the film of "cement milk". The essence of the method is to use an acid solution that destroys the film. At the same time, the chemical method adversely affects “normal” concrete,
  • The mechanical way. It consists in the forced removal of the film of milk with special equipment: sandblasting or shot blasting machine. This is a rather time-consuming and expensive method, which cannot remove the milk film in hard-to-reach areas,
  • The method of a water-air or water jet under pressure. It is one of the simplest and cheapest method. The method cannot be applied when a water-insoluble film is formed on the surface of the substrate, since instead of removing it, an adhesive oil film appears on the surface of the substrate,
  • Manual removal with a universal tool: a metal brush or a metal nozzle on an electric drill, hammer or angle grinder (grinder).

Removing a film of cement milk using solutions of hydrochloric or acetic acid is an acceptable but technically dangerous method. In this case, there is a need to protect the base from the harmful effects of hydrochloric acid using a solution of concentrated alkali.

The solution is applied to the concrete base, after which it is thoroughly washed with running water. This process reduces coating erosion and requires strict adherence to Safety Rules and the use of personal protective equipment for workers.

The first and most important thing to understand: limescale is a stone

Acids work with a stone, and period. Hence all the advice on the Internet on the use of wine vinegar or citric acid to solve this problem, and along with many others. But not ammonia, not soda, and yet God knows what. Understanding this, you will not try to wash off lime with oven or skin products. The stone is removed only with acid.

But why then vinegar can not cope with a plaque-stone?

Homemade acids - wine, table or apple vinegar, citric acid are most often used. But they are hopelessly weak for difficult cases - try to wash real rust with vinegar. You will have to soak the bath for a week, and not the fact that after that it will survive. We even add vinegar to borsch. We do not think, in fact, that he is able to cope with serious stones.

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Removing rust from fittings

If for some reason a part of a metal element is found on the floor, which should be inside the concrete, rust spots will probably appear on the surface soon. It is recommended to solve this problem right away, without putting off the case in a long box and not contributing to the further spread of corrosion. Of course, rust must first be removed. This can be done by lightly grinding the floor. After that, with the help of a sealant, we abundantly coat the area above the protruding metal. The last stage of floor restoration is the application of a semi-dry screed on the floor with a thin layer. After drying, gently grind the problem area flush with the common surface.

Water rust removal

If rusty drips on concrete formed under the influence of water, as often happens, we use folk, but very effective methods. The main tools will be lemon juice, white or apple cider vinegar, a cleaning product with the presence of oxalic acid in its composition. Regardless of the selected tool, we focus on the following procedure. We apply the working fluid to the area with rust and let it stand so that the agent penetrates into the pores of the concrete. After that, using a brush for metal, we intensively clean rusty stains. With a large amount of rust, this procedure is recommended to be repeated several times. Upon completion, wash the area with clean water.

Or vice versa - “here I used vinegar, and it helped”

If your grandmother’s help helped, perhaps you didn’t have any raids? And all this you could just wash with water and soap and a sponge or any means from the store. Why transfer vinegar and spoil the air in the apartment? I often come across the fact that they try to wash everything with vinegar - building dust after repair, soap scum and even grease. And they say it helped. But just about the same way ordinary water helps to remove traces of whitewashing or soap deposits. And fat needs to be washed with alkali - this is generally the opposite of acids.

Maybe then try hydrochloric acid, is it more powerful?

Yes, there are such tips on the Internet - take hydrochloric acid and wash it. They may be interested in a mistress tired of the fight against a raid, but I categorically do not recommend this. Because it is a very powerful acid that will burn your hands, eyes, taps and bath without proper use. Why take the risk?

And if you rub with powder?

No need - from friction, the stone will collapse and mix with the powder. You will get a superabrasive mixture that will scratch everything. Often in this way they try to wash off the cement on the windows - rub with a sponge and powder so that it crumbles. Therefore, most of the windows in our country are scratched even before the owners enter the new apartment.

What to wash then?

Buy a good household product in the store for about 10 rubles. I repeat - it’s definitely not the cheapest, but the middle segment of household cleaning products will remove plaque for sure. Why not cheap? Because it contains the most aggressive acids or their combinations - these are the very products that destroy our faith in technological progress and at the same time our chrome-plated taps, acrylic, natural stone, marble, granite and matte tiles.

These tools can be used on very primitive and stable surfaces with very competent work with them. And not suitable for most modern interior solutions. It is about them that they write on the Internet - chemicals are very aggressive, vinegar is better. To summarize - cheap chemistry is very aggressive. And the good from the store is very good.

A good household tool - time. Time is two.

Usually they write - wait 5 minutes and rinse with water. Here, perhaps, marketers are deceiving us - apparently, to give non-existent superpowers and sell more. This is the secret - it takes much longer. When we entered the office, we inherited a toilet with rusty trickles - we applied our professional product on the five minutes indicated on the label - and nothing happened. And then they inflicted it again and forgot about it - after two hours they came to their senses, ran in, washed off with water and a sponge - and the toilet became white, as in an advertisement. So we learned the secret of getting rid of a raid, which we gladly recommend to everyone, and it helps - you just need a lot more time.

During this time, the acid crushes the stone and divides it into many small particles. Before the remedy, you try to remove the whole stone with a knife, and after that - already each small part individually. And it is much simpler - you don’t need a knife here, just a sponge. Therefore, the stronger the stone, the longer the tool should work.

And summarize briefly, without water

Here's what to do when flying:

  • Make sure that you really have limescale or rust, and ordinary soap and water will not help you.
  • Buy a good tool for plaque for 10 rubles - usually on the packaging it is written "to remove limescale." For rust, it is also suitable. If you think it’s expensive, I’ll say that it’s enough for a year. And when you get rid of plaque - follow the instructions, leave for 5 minutes - this will prevent strong stones in the future.
  • Read the instructions - make sure that it is suitable for your surface. If it is forbidden, then you cannot move further with it. But this is rare.
  • Additional check (except when prohibited) - apply to an inconspicuous area for 5 minutes. If nothing is spoiled - you can use it.
  • Put on the plaque zone - to start, hold the hour. During this time, the stone will crumble a little, and it will be easier to remove from the surface. Sometimes this time is enough. If not, apply again and rinse again, rubbing with a sponge. If the raid is strong, you will need to make several such approaches - apply, leave for a while, rub, rinse. Time depends on the severity of the plaque and surface material, but on an enameled toilet bowl and huge rust can be applied even at night - it will only benefit from this.
  • If all else fails and the rust is not gone, then it has corroded the surface. Here you either need to come to terms with this, or replace a bath or a toilet bowl - this also happens if you start the process hard. Then even professional tools will not help - only a replacement.
  • Following my advice, I brought my mom a household appliance of a proven brand that I have at home - when I run out of a professional remedy, I don’t go for an addition to the office, but go to the nearest store. I applied it to the bathtub and walls for an hour, then washed it off with water and a sponge - 80% of the plaque left immediately. She will remove another 20% from the second time. And without a knife.

Use good tools and these simple tips - and you can handle almost any plaque or rust. Good luck!

Elena Simonchuk, co-owner and director of Cleanny (cleaning houses and apartments)