How to remove old paint from metal?

Before painting any metal structure, it is always better to remove the old coating and remove rust. It should be recalled that before painting the metal surface is first degreased, primed and then painted several times. This technology is designed for maximum adhesion of the iron surface to the coating film, and at the molecular level, when one material penetrates another. Agree, breaking such a connection is very difficult and you will have to work hard to solve the urgent issue of how to remove old paint from metal. In the article, we will introduce you to the methods of removing paint and tell you which tools and tools to use, and which are better to refuse.

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How to remove paint from metal?

In most cases, it is better to remove the previous layer of varnish or paint before painting. 80% success and the quality of the painting process, including the durability and uniformity of the coating, depend on thorough preliminary preparation.

Ways

The main options for cleaning the surface:

• Mechanical.
• Thermal.
• Chemical.

Technology Selection Criteria

Each method has its advantages and disadvantages. In addition, the choice of method depends on several factors:

• The surface on which the paint layer is applied.
• Further plans for the use of metal products.
• The adhesion strength of the coating to the base.
• Tool availability.
• Budget allocated to the cleaning process.
• Type of paint, number of layers. Paints are mainly: water-based, acrylic and oil.

Important! If you do not know the type of paint applied to the surface, you will have to experiment with methods and means to remove old paint from metal.

Consider the methods of metal cleaning in more detail.

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Mechanical manual method

This method is most popular when it comes to a relatively flat surface. You can remove old paint from metal manually using sandpaper or a metal brush, as well as using an electric tool, for example, using a special nozzle on a drill.

Technology Advantages:

• Helps to completely get rid of old paint, in addition, removes rust and dirt.
• Convenience in processing a small area of ​​metal surface.

The disadvantages of the method:

• The process is very laborious.
• Take a lot of time.
• Not harmless. You will have to inhale a lot of dust when cleaning the surface.
  

Materials

For the mechanical method, you will need a huge arsenal of tools:

• Putty knife.
• Sandpaper.
• Rasp.
• Grinding nets.
• Files.
• Sandpaper holders.
• Other abrasive materials.

Machining technology:

1. Remove the top coat with a metal brush, spatula or knife.
2. Pull sandpaper on a wooden block and strip the paint until pure metal appears.

Important! Pay attention to the grit (grit) of the abrasive material. If you started work with sandpaper, the grain of which is R-80, then you need to finish working with paper with grit R-320/420. On the back of the sandpaper is always indicated grit.

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Mechanically electrified method

To clean large surfaces, use an electrified tool, for example, an angle grinder (popularly a Bulgarian). The machine will do the physical work for you, while the physics of the paint removal process will be completely preserved.

On an industrial scale, paint is removed using a sandblasting machine. This is the most radical method from the group of mechanical effects. The material and shape of the metal surface do not matter.

Important! Process technology: a stream of quartz sand or other abrasive is directed to the surface to be cleaned, grains of sand, hitting it, clean the old layer of paint.

Advantages of using electronic devices:

• Quickly and efficiently cleaned.
• The minimum expenditure of time and effort.

Disadvantages of technology:

• Necessary electrical equipment is not always available.
• The high cost of tools.
• The need for certain skills to work with equipment.
• Damage to the top layer of metal. The thickness of the metal to be cleaned must be at least 2-3 cm, otherwise, dents may occur.

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Thermal method

It is possible to slightly ease the process of removing old coatings by heating the surface. Under the influence of high temperature, the coating will become soft, and it can be cleaned even with an ordinary spatula.

Instruments

You can use for heat treatment:

• Construction hair dryer. This tool gives a temperature of an air stream of up to 600 degrees, so the paint coating can even be burned out.
• Gas burner.
• Blowtorch.
• Oxygen acetylene welding.
  

disadvantages

This is the most radical method used to remove old paint from metal. It often does more harm than good. It is rarely used, since the thermal method has a lot of disadvantages:

• Fire hazard.
• Not every material can tolerate such an effect. The thermal method is not suitable for sheet iron, cast iron, galvanized sheets.
• Metal can deteriorate from high temperatures, become soft and brittle due to carbon burnout.
• After thermal exposure, scale appears.
• Unsafe for health, as you have to breathe burning.

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Chemical way

The best way for a person who is interested in how to remove old paint from metal, for example, from a battery, is to use special chemicals that are safe and quite effective. Popularly, such substances are called “washes”, but in fact, they do not wash off, but corrode a layer of varnish or paint.

Types of funds

Rinses are offered by manufacturers of various consistencies:

• Gels.
• Pastes.
• Water soluble powder.
• Sprays and liquids for removing old paint from metal.

Important! All these tools are great for working with metal of any complexity and relief. The price of products depends on the manufacturer.  

Application

All paints and varnishes are soluble to one degree or another, so choose a suitable solvent, soften the paint, and then remove the old coating with pinch movements.

Depending on the chosen wash and its consistency, proceed as follows to remove old paint from the metal:

1. Apply the gel or paste to the surface of the metal and leave it for 20 minutes - 20-30, as indicated in the instructions. Old enamel will swell, become soft and can easily be removed with a spatula or rag.
2. Aerosol and liquid for removing paint from metal also quickly impregnates the surface - after 1-2 minutes. After a chemical reaction, the paint begins to separate easily and all you need to do is remove it with a spatula.

Important! After cleaning, wash the surface with soapy water and apply a corrosion-resistant primer.

Advantages of the chemical method:

• Quick effect.
• Ease and simplicity of execution.
• Reliable, and in some cases irreplaceable.

Cons of the chemical method:

• Toxicity, albeit insignificant.
• Substances pass before coating more than two years ago.Dried paint preparations only moisturize, but do not remove.
  

The best manufacturers and brands of washes

The chemical method is quite simple, but it’s hard to find a quality manufacturer of washes.

Well established:

• “Prestige” is a gel-wash of a domestic manufacturer.
• Solvent No. 646.
• BODY and ABRO are foreign companies.

Important! For greater effectiveness, first apply one coat of paste, gel, metal paint remover, and after a while repeat the procedure.

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Paint Safety Guidelines

To remove the old coating from a metal surface, it is often necessary to combine and resort to all methods: after heat treatment, scrape off the scale with a spatula or apply liquid to remove paint from the metal, and then treat the surface with sandpaper.

However:

1. With all methods and means, do not forget about safety: be sure to use protective gloves, goggles and a respirator so as not to damage the skin of the hands and not to inhale toxic fumes.
2. Be especially careful when working with heaters, lamps and burners to avoid burns.
3. In addition, all procedures are carried out in a well-ventilated area, and preferably on the street.

Do not ignore safety rules, so that after cleaning the metal, you will not solve another question, how to fix the consequences of your work and improve your health.

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Stock footage

We hope that the information received helped you choose a reliable and quick method of removing old paint from a metal surface and it is ready for a new coating.