How to remove paint from metal fittings with Hydrochloric acid

Friday, March 10, 2023
We're definitely a fan of using acid to remove rust from tools and screws but have you ever thought of using hydrochloric acid to remove paint from metal?

Sometimes I paint the house. I'm a bad painter as I paint the fittings.

Fittings my wife would rather I just left alone.

So today, I decided to do something about it and remove the paint from my living room window fittings with some good old HCL. It was a good experience so I've turned it into a guide, using images from the fittings.

Guide to Using Hydrochloric Acid to Remove Paint and Grime from Metal

Removing paint and grime from metal can be a daunting task, but with the right approach, it can be an easy and effective process. One effective method is using hydrochloric acid, commonly known as HCL acid. However, caution should be taken when using HCL acid due to its corrosive nature. In this guide, we will discuss the safety measures, effectiveness of HCL acid, the chemical reaction, the steps to soak the metal, and safety advice when using HCL acid.

Safety Measures

HCL acid is a highly corrosive substance that can cause severe skin and eye damage if not handled properly. Therefore, it is important to wear protective gear such as gloves, safety goggles, and a respirator mask. Also, ensure that you work in a well-ventilated area to avoid inhaling the fumes.

Effectiveness of HCL Acid

The effectiveness of HCL acid in removing paint and grime from metal depends on the type and age of the paint. HCL acid is more effective in removing older and oil-based paints than newer and water-based paints. Therefore, it is advisable to test the acid on a small section of the metal to determine its effectiveness.

Chemical Reaction

HCL acid works by breaking down the chemical bonds in the paint, which results in its dissolution. This reaction produces carbon dioxide gas, which is why you may notice bubbling during the soaking process.

Steps to Soak the Metal in Acid

You're wearing gloves and eye wear when doing this right?
  • Prepare the work area by covering it with a plastic sheet or newspaper to protect the surface from the acid.
  • Dilute the HCL acid according to the manufacturer's instructions, probably 10 - 15 percent in water.
  • Pour into a plastic container that will allow for full submersion of the metal in the solution.
  • Submerge the metal in the diluted acid, making sure that it is completely covered.
  • Allow the metal to soak for about 30 minutes, or until the paint begins to soften:metal soaking  in HCL acid
  • Rinse the metal thoroughly with water to remove any remaining acid.
  • Use a metal wire brush to remove the softened paint. 
  • Rinse again as need be.
Here's the actual results of this work:

metal and paint cleaned with acid

paint removed from metal with hydrochloric acid

Safety Advice

When working with HCL acid, ensure that you store it in a safe place, away from children and pets. Also, avoid mixing it with other chemicals as this can result in a dangerous reaction. In case of accidental contact with skin or eyes, flush with plenty of water and seek medical attention immediately.


Using HCL acid to remove paint and grime from metal can be a simple and effective process, but caution should be taken when handling the acid. By following the steps outlined in this guide and taking the necessary safety measures, you can achieve a clean and polished metal surface.

Check out our guide to cleaning bathrooms and rust stain with Citric acid
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