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Practical tips: how to paint radiators

We talk about the features of painting different types of batteries, introduce suitable paints, and give detailed instructions for preparing and painting radiators.

Over time, brand-new radiators lose their attractive appearance. Spots of ingrained dirt, streaks of rust, and cracks in the paintwork appear on them. Sometimes its fragments break off and the surface becomes uneven. But at the same time, the equipment works properly and heats the room efficiently. Therefore, there is no point in changing it. We just need to return it to its original appearance. We will analyze all the nuances of painting heating radiators: from choosing enamel to its correct application.   

Which batteries can and cannot be painted?

Painting is not “indicated” for all types of heating devices.

Which ones are possible?

It is possible and even necessary to paint cast iron sectional products. This protects them from corrosion and does not in any way affect the level of heat transfer. Steel panels can also be painted, but provided that an aerosol composition is used. In this case, it is difficult to apply an even layer with a brush. This is not the case with other types of equipment. Let’s look at the features of their painting.

Which ones are undesirable?

Plate models

They are distinguished by the presence of a large number of thin heat exchanger plates. Painting them is extremely difficult and undesirable. This may reduce the heat output of the device. It is impossible to properly paint a plate radiator with a brush; there are too many closely spaced plates. Relatively even painting can be achieved by disconnecting the product from the pipeline, removing it from its mounts, and placing it on a horizontal base. 

In this case, the paint is applied with a spray gun, or a spray product is chosen. However, this does not guarantee high-quality application. Often unpainted areas remain and unsightly streaks form. Manufacturers do not recommend painting plate devices completely. Only removable decorative panels can be painted. The remaining elements are cleaned and protected from dust and dirt. 


The design of convector heaters involves the presence of finned pipes. There are many such ribs-plates. It is very difficult to paint them well, and even undesirable. As with plate equipment, the application of paint can impair heat transfer. Therefore, only the metal casing covering them should be painted. It is removable, which makes the task easier. 

Sections made of bimetal or aluminum

Modern sectional models are available with high-quality powder coating. They do not need to be painted during their entire service life. They retain their attractive appearance and performance characteristics. If you still need to paint such a device, use only aerosol products or a spray gun. But even in this case, there are no guarantees of high-quality application. In addition, there is a possibility of reduced heat transfer after painting. 

How to choose a paint product

The correct choice of paint and varnish materials is very important. If you use the wrong composition, after a short time it will become unusable and the repair will have to be done again. You need to know that the paint for a radiator must meet several requirements at once. Let’s list them all.

Composition requirements

  • High-temperature resistance. The composition must retain its properties at a temperature of 85-90°C throughout its entire service life.  
  • Safety. The presence of toxic substances in the composition is unacceptable. When heated, they will be released into the air, which is dangerous for people and pets.
  • Color fastness. The product should not fade or change color when exposed to high temperatures and ultraviolet radiation. 
  • Anti-corrosion protection. Metals are susceptible to corrosion; anti-corrosion additives in the paint should protect the body from rust. 
  • Wear resistance. Abrasion resistance must be high so that the coating does not become thinner due to contact with various objects and periodic cleaning.
  • High adhesion. The solution must adhere well to the substrate to prevent peeling during frequent heating and cooling cycles. 

The right product will fulfill all these requirements. It is best to apply a composition marked “for radiators,” but you can choose any other with suitable characteristics. 

Several types of paints are suitable for painting heating appliances; we will briefly describe each of them.

Acrylic mastics

These are water-dispersion compositions based on acrylic. Water is used as a solvent, which explains the complete absence of toxic substances and unpleasant odors. Safe for humans. Acrylic sets and dries quickly. At room temperature, this takes about 30-40 minutes. A dense water-repellent coating is formed that is sufficiently resistant to mechanical damage.  

Acrylic easily tolerates high temperatures and can be applied to a hot base. There is no unpleasant odor. This is the best solution on how to paint a hot radiator. The whiteness coefficient of acrylic mastics is 96%. Therefore, they give a bright white tone and rich, beautiful shades. The acrylic coating is flexible, does not crack, and does not peel off. Its service life is seven to eight years. 

Alkyd enamels

Their base is alkyd resins mixed with thinners, pigments, and fillers. These are substances of varying degrees of toxicity. When working with enamels, aliphatic and alcohol solvents with an unpleasant, pungent odor are used. It persists during painting and for some time after it. Therefore, they work with alkyd preparations only outdoors or in a ventilated area. Upon completion of painting, it must be left until the product is completely dry.

Alkyd enamels are heat-resistant, have an anti-corrosion effect, and provide an even, dense coating. It is stronger than acrylic and better resists chips and scratches. They produce matte, semi-matte, and glossy pastes. The latter better preserves the original color. However, they all acquire a yellow tint over time. Glossy begins to turn yellow later than matte. 

These are the main varieties recommended for use. There are others too. Hammer mastics look good on batteries. This is a type of alkyd composition. After drying, they form a coating reminiscent of embossing. It looks like it has been beaten with a hammer, which is what gave the product its name. Thanks to this, small unevenness and other defects in the base are not visible.

It is better not to use oil products. These are preparations based on oils, natural or synthetic. They used to be very common, but are gradually leaving the market. They are short-lived, not heat-resistant enough, and quickly lose their attractive appearance. Sometimes, in the old-fashioned way, they use silver, a mixture of varnish and aluminum powder. It is heat-resistant and does not affect heat transfer. But at the same time, it has a persistent unpleasant odor and quickly loses its attractive appearance.

How to paint a cast iron battery

Start with a careful inspection of the heater. It is important to understand what condition it is in; this will determine the complexity of the upcoming preliminary work. There can be three options.

The first one is the best. In this case, the surface of the device is smooth, without cracks or chips. This means that preparation will be minimal.

The second case is if the old coating is a little cracked and peeling. We will have to work hard to correct the detected defects.

And the third, worst one is when only fragments of old paint remain on the heater. In this case, serious preparatory work is required, which consists of completely removing the worn-out enamel. Otherwise, it will not be possible to apply the new design in a high-quality manner.

After a careful examination and diagnosis, the main work begins. We will step by step explain how to paint a heating radiator using old paint. 

Preparing for coloring

First, the equipment is completely cleaned of accumulated dust and dirt. It is best to first vacuum the surface. A good result will be achieved by using a crevice nozzle, which is used to remove dust from the internal plates of the sections. After dust removal, begin washing the device. To break down the fat, prepare a washing solution with soap or dish soap. Be sure to wash off greasy stains. If this does not work, use aggressive chemicals such as oven-cleaning products.

The washed battery is left to dry. Further actions depend on the state of the device. If there are only small defects on it, they need to be cleaned and carefully puttied. Any automotive putty will do. The repaired area is dried and cleaned again, achieving smoothness. The most difficult manipulations await if the old finish is partially peeled off and covered with cracks. It needs to be removed.

You can do this with your own hands in two ways. The first is mechanical. To remove enamel, use a metal brush. Rub the base with force, gradually removing the paint. This is a very long, labor-intensive, and dusty job. You can simplify it if you use a power tool. For example, a grinder with a grinding wheel or a brush. Cleaning must be done carefully to avoid damaging the equipment. 

The second method is to use a chemical remover. Take any suitable drug, apply it to the surface, cover it with plastic, and wait for the time indicated on the package. After this, the swollen enamel is removed. Important note: it is strictly forbidden to use aggressive chemicals on a hot base. The remover is toxic and has a pungent odor. Heating only intensifies this. 

One more thing. Properly selected chemicals are harmless to cast iron or steel bases but can destroy hemp if it is used to seal threaded joints. Then after turning on the heating, there will be leaks.

After removing the enamel, the equipment is cleaned again. The surface prepared for painting is degreased, allowed to dry, and then primed. Select a primer for metal, with anti-corrosion properties and necessarily compatible with the selected type of enamel. The primed base is allowed to dry. 

Radiator painting

Prepare two brushes for painting. One is regular, the other is with a long curved handle. It makes it easier to paint the inside of the sections. Both brushes must be thoroughly fluffed before use so that the poorly retained bristles fall out.

Painting begins from the inside of the equipment. They move from top to bottom. If you do the opposite, there is a high risk of drops and streaks appearing on a freshly painted surface. 

The outer part is painted similarly. Start from the top half and gradually work your way down. The solution is rubbed over the base so that the thickness of the coating is uniform. The painted surface is allowed to dry completely, then a second coat is applied. If the first laydown is not very straight, this can be corrected. The dried paint is sanded, and drips and drops are removed. Then re-paint and leave until completely dry.

Features of painting aluminum and bimetallic radiators

All that remains is to figure out how to paint a battery made of aluminum or bimetal. It is clear that experts do not recommend doing this. Moreover, if the equipment is under warranty, it loses it after painting. However, you can still paint the device. Preparation for staining is carried out in the same way. The surface is washed, dried, degreased, and primed. Minor defects must be corrected before priming. 

Cracks and chips are filled with auto putty, and allowed to dry and cleaned. After this, they begin painting. You can use auto enamel. It sets well and dries quickly on a hot base. Therefore, you can use it to paint radiators during the heating season; it will dry in 20 minutes. But this must be done with caution. Be sure to open the windows and wear a respirator. The can is brought at a distance of 25-30 cm and smoothly moved from top to bottom. You can’t stay in one place for a long time; drips will appear.  

If alkyd or acrylic compositions are chosen for painting, it is not recommended to use a brush or roller. A spray gun or spray gun is best. They will help you apply the paint evenly. Before work, it is advisable to disconnect the equipment from the heating system, remove it, and place it on a flat horizontal surface. This way the paint will lie as evenly as possible. 

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