Video: How To Paint Metal Correctly
More recently, the very idea of painting metal surfaces with water-based paints seemed utopian. The most common of the metals - iron oxidizes very quickly in the presence of water, and here is water-dispersion paint.
Conventional waterborne paints are of course not suitable for this purpose. In this case, specialized materials are needed that form a dense protective coating, have anti-corrosion properties and have good adhesion to metal.
Scientists were not able to solve all these problems immediately. Now in Europe, it has come to the point that water-based paints are used in such difficult areas as the automotive and shipbuilding industries. We will not run that far yet, but consider the possibility of painting metal surfaces in construction.
Let's start with the hardest part - the roof.
Metal roofs can be divided into three groups according to the material used.
The first is made of black iron.
The second is made of galvanized iron.
The third is made of non-ferrous metals: aluminum, its alloys, copper, etc.
The third group is extremely rare due to its high cost, so it should not be considered.
The first and second are much more affordable and widespread, although much more expensive than slate.
With black iron, everything is clear, it must be painted without fail. Usually for these purposes in Russia, oil and alkyd paints are used in the old fashioned way.
Those who like to paint often can continue to do so. For the "lazy" we can recommend acrylic water-dispersion roof enamels with anti-corrosion effect. Such a coating will cost you a little more than oil or alkyd paint, but it will last much longer. In addition to the fact that acrylic coating is more durable in atmospheric conditions, it also has a higher elasticity that remains unchanged from aging. In the case of metals, this is very important because they have large linear expansion due to temperature fluctuations.
Oil and alkyd paints have less elasticity than acrylic paints, and they also lose it during aging. As a result, at some point, this type of paint will simply begin to flake off the metal surface.
Painting a galvanized roof is an ambiguous operation. A zinc layer will protect the iron well for 10-15 years. After this period, it is necessary to paint. However, it is better to paint the new galvanized roof. This will prolong its life and give it a more pleasant appearance. Galvanized iron has a more passive surface than black iron. Therefore, in this case, a specialized material with even greater adhesion and elasticity is required than in the version with ferrous iron.
Oil and alkyd paints are generally not suitable for this task. On a galvanized roof, they will last no more than one season, and specialized acrylic enamel will delight you for many years.
If a sheet of iron is corrugated in a certain way, and then painted with anti-corrosion acrylic enamel, then you will receive an analogue of a metal tile, only several times cheaper.
One company has already taken advantage of our recommendations and successfully sells painted galvanized corrugated sheets, creating competition for imported counterparts.
To tell the truth, when creating water-based paints for metals, we ourselves did not expect how wide the possible range of their application would be. For example, they turned out to be simply irreplaceable when painting various explosive and fire hazardous objects. All solvent-based paints burn well, and their vapors are also explosive. When an ordinary object is painted, it is not so bad, but if it is an oil storage or gas storage, then there is no time for jokes. The slightest spark, not to mention a cigarette butt, and a brigade of painters can be said goodbye, as, indeed, with the object. Water-dispersion materials are absolutely safe in this respect.
There is a successful experience in painting various metal structures and structures: hangars, garages, fences, gates, even trucks and railway cars.
A small amount of rust is not a problem here. Anti-corrosion additives not only passivate its further spread, but also transform the already formed one.
If the metal surface has a more severe rust damage, then you can apply a specialized anticorrosive acrylic primer with a rust converter, and then paint. And all this is fast, odorless and with maximum convenience in work.
So, when you need to paint a metal surface, do not rush to put on a gas mask or a cotton-gauze bandage, you will not need them when working with acrylic water-dispersive materials.