- What paint will withstand heat
- Working with aluminum and bimetallic radiators
- Preparation for painting
- Do I need to prime
- We effectively restore painting of radiators
If you are going to update the appearance of radiators, take your time and study the specifics of this type of painting work. We have prepared a guide on choosing paint for radiators, as well as on the technique of performing work, which will allow you to achieve a resistant, durable and uniform coating.
What paint will withstand heat
Most modern alkyd and nitro enamels are able to withstand the heating of hot water radiators without being destroyed. The main task is to ensure that the paintwork retains its color and fresh appearance for as long as possible. It is also desirable that the painting is not sensitive to mechanical damage and cleaning chemicals. White or pastel colors are recommended..
For cast iron batteries and steel radiators without a decorative casing, it is recommended to use heat-resistant acrylic enamels. They have good hiding power, do not crack or turn yellow, and a faint hint of odor disappears completely after drying for 5-8 hours and does not appear when heated.
Of the coloring pigments, titanium or zinc oxides are preferred as the safest and most durable. Since this type of paint usually has a water-dispersion base, using dyes of the general spectrum, it is possible to achieve tinting in the desired tone. Acrylic enamel manufacturers recommend Rohm and Haas, Sniezka, Dufa or Parade.
Alkyd enamels are often used to paint heating pipes, but they are also quite allowed to paint batteries. Especially old-style cast iron, where smoothness and gloss are not so important, but it makes sense to save money. The paint marking must have the number 8 in the third group of designations immediately after the letter code. For example, enamels such as AC-85 or two-component GF-820 are well suited.
Oil and water-based paints without polymer binders are not used to protect heating devices. Although they have high resistance to cyclic heating, they are not very convenient to apply and clean. Please note that now we are talking about ordinary paints, and not about enamel.
Working with aluminum and bimetallic radiators
It is recommended to separately assess the compatibility of paints, because in most cases radiators are painted over an existing coating, which no one plans to completely remove. For example, for a high-quality restoration of the appearance of modern aluminum radiators with an enameled surface, a high-viscosity paint is required, while maintaining good flow on glossy surfaces. Usually in the description of such paints indicate “For ceramics”.
Thin-walled radiators can equally well be painted with alkyd enamels, if the paint application technique allows you to maintain an attractive appearance. Purely chemically, the compositions do not conflict, but preliminary mechanical treatment will be required to obtain sufficiently high adhesion.
It should also be noted that water-dispersed enamels fit well and are used over alkyd and others. But not in the reverse order: the application of alkyd enamel over acrylic usually negatively affects the strength characteristics.
Also, do not bake aluminum, bimetallic or steel radiators to remove existing paintwork. It is much more correct to clean the enamel gloss with 400 grit sandpaper and apply several thin layers of new paint. If there is a struggle for perfect smoothness and the appearance of chips of old paint is undesirable, only the front lamellas of the radiator can be cleaned to metal instead of subjecting it to heat treatment.
Preparation for painting
There are two options for painting: for the existing coating and from scratch for metal. In the first case, it is required to knock down the glassy crust of the old enamel by treating the entire surface of the battery. If there are hard-to-reach areas, it means that mechanical impact on them is unlikely, therefore, superficial sanding will be enough.
Uncoated metal radiators can carry traces of grease or soot after removing the mold. They do not need to be cleaned to a metallic shine, but it is advisable to treat at least a rust converter. All traces of dusty deposits should be eliminated, which, when wetted with a paint and varnish composition, can distort the color of the latter.
In both cases, the surface to be painted must be absolutely dry, free from contamination of any kind and must be degreased. The quality and cleanliness of the surface preparation must be very high, including on internal ribs and lamellas. Otherwise, due to cyclic heating, any delamination will appear, and the appearance of the coating will be hopelessly damaged..
Do I need to prime
Painting radiators from scratch should be carried out on the preparatory layer. For this, use primers on the same basis as the enamel to be applied. In general, it is recommended to purchase a neutral pigmented primer with a corrosion inhibitor, so the likelihood of red spots is minimized.
By the way, the whole difference between a primer and a paint comes down to the ability of the latter to form a protective smooth film. Perhaps this will help to better understand the essence of preparation for painting..
Before further work, the primer must be completely dry and fixed. Always keep in mind the temperature of the batteries and achieve maximum adhesion between successively applied layers.
We effectively restore painting of radiators
Immediately before painting, you must provide all the necessary conditions at the painting site. Radiators must be turned off and brought to room temperature +/- 10 ° C, but not lower than + 15 ° C, otherwise the base will not have time to dry and properly polymerize. At the location of the radiator, all dust and cobwebs should be removed: floor, walls, window sills, and especially their lower surfaces should be wiped off with a damp cloth.
For the best quality painting of the radiators, they will need to be removed. This will provide access to all interior surfaces. In order for the protective coating of the radiator to work in a complex manner, it is imperative to paint the rear part and the lower edges of the lamellas, otherwise paint shedding may occur, starting from the “bald patches”. The radiator is removed for a short time and precisely for painting the back side: when it is finished, you can make a reverse installation without leaning the body against the wall.
Painting the front ends by working with a curved brush along the inner ribs and sipes. The paint must be rubbed well and not try to cover the surface with one layer, you still need at least two. At the same time, watch for the appearance of drips and remove them in time.
When the inner surfaces are painted and the paint has lost its tack, they are re-enameled together with the front panels. Alkyd enamels can be applied with a soft long bristle brush, preferably natural and combed out. It is better to apply acrylic water-dispersion and nitro paints from a spray gun or a spray gun, at least the cheapest one. As a last resort, you can use a foam swab. When applying one or two general coats, it is very important to achieve the most complete, continuous coverage and eliminate the gaps allowed when processing the inner edges..
Each enamel for radiators has its own full polymerization period, on average from 5 to 12 hours. It is advisable that all this time the radiators remain off. This rule applies even to paints that, according to the manufacturer, can be applied to hot surfaces and which, to put it mildly, do not cope with their task. With a significant temperature difference on different sides of the applied layer, normal setting of the coating is impossible, exceptions to this rule are very rare. If you have done all the work correctly, painting radiators will delight you with brilliance and cleanliness for the next 5-7 years.