Hydrochloric acid to remove rust

This blog post will answer the question, “hydrochloric acid to remove rust” and cover topics like how to remove rust with hydrochloric acid, and frequently asked questions related to the topic.

How does hydrochloric acid remove rust?

Rust can be removed with hydrochloric acid by following the steps given below:

  • First, make sure you’re wearing gloves, eyewear, and other protective gear. 
  • Dilute your hydrochloric acid solution with 10 parts of water, always putting acid into water and never the other way around. 
  • Scrape the rust with an acid and a scrubbing brush until the corrosion is gone.

How to Get Rid of Rust Using Hydrochloric acid?

Hydrochloric acid is a powerful chemical cleaner that is used to smooth ceramic and fiberglass objects by housebuilders. Surfaces may be eaten away by the powerful acid. To eliminate rust spots, dilute the chemical and take the necessary measures to ensure that it does not harm your surface, hurt your eyes or lungs, or aggravate your skin. To remove corrosion from porcelain, fiberglass, brickwork, and tiles, use hydrochloric acid. It should not be used to prevent corrosion from stainless steel.

1st step

Put on protective gloves, eyewear, and a dust mask. Hydrochloric acid fumes may irritate your eyes, and contact with the substance dries up your skin.

2nd Step

To air the workstation, open the doors and windows in the area.

3rd step

Fill a 12-gallon bucket halfway with water.

4th step

Fill the other half of the container with muriatic acid. To blend, stir everything together.

5th step

Put a brush into the mixture and use it to apply the paint. Do not allow the solution to come into contact with your skin.

6th step

The solution should be applied to the rusted area.

7th step

Allow at least 1 hour for the solution to settle on the rusted area. If the area dries out, reapply the solvent with the brush. If you have children or pets in your house, never leave the hydrochloric solution or the area alone.

8th step

Remove the corrosion by scrubbing it away.

9th step

To avoid the hydrochloric acid from eroding its way through the surface, quickly wash the area with clean water.

10th Step

Allow for total air drying of the area.

Materials Needed
Rubber gloves
Dust mask
Hydrochloric acid

How hydrochloric acid removes rust from metals?

When muriatic acid is used to clean rusted metal, two chemical reactions occur. The first happens when corrosion, which is ferrous (III)oxide (Fe2O3), comes into contact with the acid:

6 HCl + Fe2O3 → 2 FeCl3 + 3 H2O

When dissolved in water, FeCl3, or iron (III) chloride, is a yellowish chemical that washes away readily. However, washing it reveals the underneath iron to the acid, resulting in the following reaction:

Fe + 2 HCl → FeCl2 + H2

The light blue complex FeCl2, or iron (III) chloride, lacks the structural integrity of iron and remains as a kind of rust while the hydrogen gas (H2) rises up to the surface and leaves.

If you’re going to use hydrochloric acid to eliminate corrosion, use just enough to initiate the first reaction without initiating the second, then wash and dry the steel as soon as possible. If the second reaction happens in excess, the acid might easily do more damage than benefit.

Dilute hydrochloric acid is also known as muriatic acid, and it has the same chemical formula: HCl. Prior to the early 19th century, when French scientist Joseph Louis Gay-Lussac invented the phrase hydrochloric acid, all HCl solutions were referred to as muriatic acid, which refers to the brine solution used to make hydrogen chloride gas.

Hydrochloric acid may be used to eliminate corrosion on rusted metal, which is why steel pickling, a technique for removing patina from steel prior to marketing, uses it.

Steps of removing rust from metal with hydrochloric acid:

  • First, make sure you’re wearing gloves, eyewear, and other protective gear. 
  • Dilute your hydrochloric acid solution with 10 parts water, always putting acid into water and never the other way around. 
  • Scrape the corrosion with an acid and a scrub brush until the corrosion is gone. 
  • Finish by neutralizing the acid with sodium bicarbonate and water mixture before rinsing with clean water.

Advantages of hydrochloric acid:

Hydrochloric acid has disadvantages, but it cleans rapidly, and it’s often used to clean vehicle components and other items that can withstand a certain degree of rust without being destroyed. You may use it to wipe the rust from a wrought-iron gate, a heavy-duty chain, or old outdoor metal furniture around the home. Keep in mind, though, that it’s only recommended for stainless steel, not cast iron.

Cleaning Rust in a Safer Way by using hydrochloric acid:

Because it won’t harm brickwork, hydrochloric acid is ideal for efflorescence and brick acid corrosion removal, but it’s harsh treatment for metal. Phosphoric acid, on the other hand, is far less harsh and is used in several commercial corrosion removers. The chemical interaction between phosphorus and rust is as follows:

2 𝐻3𝑃𝑂4 + 𝐹𝑒2𝑂3 → 2 𝐹𝑒𝑃𝑂4 + 3𝐻2O

Iron (III) phosphate and water are the end products, and since iron (III) phosphate is miscible in aqueous, it simply dissolves. Because the reaction is slower, the secondary interaction between phosphoric acid and iron is easily avoided. Phosphoric acid is also easier to work with, and since it’s a marketable product, all you must do is follow the directions.

Safety measures while using hydrochloric acid:

Muriatic acid is a gas that contains hydrogen chloride. It has a foul odor and is utilized in an aqueous state. When discharged into the air, its vapors may be very poisonous. During explosions, volcanoes release muriatic acid into the atmosphere.

One of its principal purposes is to prevent corrosion since it is a powerful, corrosive, inorganic mineral acid. It may be used to get rid of corrosion on a broad range of items and materials. However, extreme caution must be used in doing so.

Concerns about safety

Because of the very caustic nature of muriatic acid, removing corrosion with it is not the simplest of operations. It is only safe for humans when diluted. It is, however, ineffective at high degrees of dilution. When utilized in its raw state, it is quite effective, although employing the acid in this form to eliminate affected rusts may cause skin irritation and eye burning. In addition to causing mortality when taken in its undiluted form, it may cause extensive burns in human tissue and substantial breathing issues. 

Useful Instructions

  • If you want to eliminate corrosion using muriatic acid despite the health concerns, dilute it 1 to 10 with water. 
  • Use black glasses and gloves and work in a well-ventilated area. Fill a spray bottle halfway with the diluted water-acid mixture and spray it on the corrosion. 
  • Scrape the rust away using a brush. The item must then be soaked in water to remove any residual acid due to the acid’s strength. If there is still rust, the procedure may be repeated. 
  • The acid’s action must be neutralized further with water and baking soda once the corrosion has been eliminated and the object soaked in water.


Because muriatic acid is so toxic, it must be disposed of in a secure and healthful way after it has been used. Anyone who has used this drug must follow the procedures for properly disposing of biohazards. While the requirements vary by state, it is normally required to be disposed of in a biohazard vessel and labeled as such. It must also be brought to a separate trash drop-off location and cannot be placed out with your normal rubbish for collection.

Muriatic Acid’s Useful Applications

If you follow all of the safety precautions listed above, you should be able to utilize muriatic acid successfully. Here are a few projects in which it could come in handy:

Rust removal

Muriatic acid’s usage to eliminate corrosion on metal is divisive since the material has the potential to accelerate oxidation in the future. As a result, the careful DIYer should only use it on stainless steel (not cast iron) that will be coated once the corrosion has been removed. 

How hydrochloric acid removes rust?

  • Scrape with a nylon brush after applying the acid at a 1:10 acid/water ratio. 
  • Neutralize the acid using a baking soda-water mixture as soon as the rust is removed (1:1). 
  • Apply the paste liberally to acid-washed surfaces and let soak for 10 minutes before rinsing with water, drying, and preparing for paint. (More detailed instructions may be found here.)

Maintenance of a swimming pool

Muriatic acid may restore the appearance of your swimming pool’s surface. Spritz a 1:16 diluted acid-to-water solution over the pool’s drained surface and let it rest for five to ten minutes. Scrape with a nylon brush to remove stubborn spots. Wash with plain water completely.

pH equilibrium in a swimming pool

Muriatic acid may be used to balance the pH of a pool if it is too high. For this assignment, you’ll need “swimming pool acid.” It will contain detailed directions and formulae for use in a swimming pool while being little more than dilute hydrochloric acid costing the same. You’ll put it in, re-test the ph values after a few hours, and then you’ll be ready for your dip!

Frequently Asked Questions(FAQs), “Hydrochloric acid to remove rust?”

Which acid is best for rust?

Phosphoric acid

Phosphoric acid is the most often used rust-removal agent. When sprayed on rust, the liquid causes a chemical reaction, turning it to a water-soluble molecule that can be washed away fast and simply.

What removes rust instantly?

White vinegar may be used to effectively remove corrosion. Rust interacts with vinegar and eventually disappears. Simply immerse the rusted metal item in white vinegar for a few hours before wiping the rust away.

How long does it take to remove rust with muriatic acid?

Allow at least 1 hour for the liquid to settle on the rusted region. If the surface dries out, reapply the liquid with the brush. If you have children or pets in your house, never keep the hydrochloric solution or the region alone.

Will hydrochloric acid clean metal?

Muriatic acid is another term for dilute hydrochloric acid, and the chemical formula is the same: HCl. Muriatic acid may be used to break corrosion on rusted metal, and that is why steel pickling, a technique for removing patina from metal prior to marketing, uses it.

Is hydrochloric acid natural?

The water-based, or water, liquid of hydrogen chloride gas is known as hydrochloric acid. It’s also the main ingredient of gastric acid, a digestive acid generated spontaneously in the human stomach.

How do you remove rust from steel?

  • Make a thick paste with water and baking soda and rub it all over the metal, ensuring sure rusty parts are fully coated. 
  • Allow an hour or so for the paste to dry on the item. 
  • Scrub the piece with steel wool or a scrubbing brush to eliminate the corrosion. Wash the paste with water and let it dry completely.





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