Desiccation with hydrochloric acid - what are the disadvantages?

Hydrochloric acid is one of the most aggressive agents that you can buy in hardware stores and household goods stores. It is very suitable for rust removal. Whether the quick leaching process with hydrochloric acid can also have disadvantages, and how to use hydrochloric acid properly, you can read here.

hydrochloric acid

The hydrochloric acid (HCl) has been known since the Middle Ages. It is considered one of the most aggressive means we know. Hydrochloric acid also occurs in our stomach, but only in low concentrations (0.1-0.2%). There she serves her to digest proteins. In English usage, hydrochloric acid is also called Muriatic Acid.

Procedure for derusting with hydrochloric acid

To quickly and thoroughly de-rust metal parts, 25% hydrochloric acid is used. It can be painted on the metal surface. However, often multiple strokes are necessary, depending on the degree of rusting.

Alternatively, the production of an acid bath is possible. In any case, a sufficiently acid-proof tub should be available.

Chrome parts should be removed before immersion, they will be dull. Other materials should be removed in any case beforehand. The rusty areas should also be degreased before immersion.

After the immersion bath must be rinsed thoroughly with water, preferably with demineralised water. Rinses should be done with both warm and cold water.

The correct procedure is thus:

  • degrease first
  • then paint or dive
  • then rinse thoroughly with water
  • Apply rust protection immediately

Advantages of rusting with hydrochloric acid

The advantage here is clearly a very fast and very thorough rust removal. Rust is removed down to the "healthy" areas. Hydrochloric acid is one of the fastest acting de-rusting agents available. Similarly effective is only phosphoric acid. 25% hydrochloric acid, unlike phosphoric acid, can easily be bought at any hardware store.

Disadvantages and possible risks

Hydrochloric acid is by no means suitable for sensitive metals. Here should be resorted to gentler rust removal, such as oxalic acid, oxalic salts or electrolysis process.

Due to the incorporation of hydrogen into the metal, which can occur during derusting with hydrochloric acid, steel rusted much faster than if the rust is removed mechanically. One should definitely think of that.

Tips & Tricks

Metal rusted with hydrochloric acid is very susceptible to corrosion and should therefore be given a rust-proofing primer immediately after derusting.

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