What exactly are penetration coatings designed for? Can they be used in the exterior and interior? On what surfaces can they be applied? Do we have to treat the surface in any special way before application of penetration coating? How do we apply penetration coatings?
Penetration is the penetration of the carrier medium into the substrate. This medium may be water, but also all solvents and other chemical agents. The active ingredient contained therein ensures the durability of the desired substrate properties. Using this technological procedure, we prepare the substrate before the subsequent treatment of the surface layer (usually the application of another layer).
Use of penetration
The function of penetration is to reinforce non-coherent substrates, unify the absorption of substrates and increase the adhesion of other surface treatments.
1. Most often, we use penetration to finish the surface after scraping off the original coatings or removing the wallpaper. Even a penetration coating with a good ability to penetrate into the base layer (carrier medium based on mineral spirits) will penetrate on a normally weathered surface only to a depth of 1 mm. If the surface is weathered to a greater depth, it cannot be reinforced exclusively with a penetration coating. It does not penetrate into the incoherent bottom layers. At that time, the penetration creates a solid surface layer.
2. If the absorptivity is not the same in all places, we can use the penetration for unification. This penetration is particularly useful in silica paints (that react to the substrate moisture).
3. If we have a hard and non-absorbent base, we can also use the penetration as a binder between the substrate and the subsequent surface treatment.
Special penetration coatings
- By penetration coating we can fix pollutants (nicotine, soot) in the substrate and thus ensure a clean surface. Such penetration coatings are called filtration coatings.
- Universal penetration can be used to impregnate unpainted, well-matured substrates in indoor areas and façades. This penetration strengthens the substrate, unifies the different absorbency of the materials, increases the adhesion of subsequent layers.
- For plaster, plasterboard, wood, chipboard, plywood or concrete penetration paints, acrylic penetration can be used. This is how we unify the absorbency of the substrates and ensure that the coatings do not peel and crack.
- Exterior and interior wood can also be protected by penetration. Such an impregnating coating will ensure its water repellency, protect the wood from weather and UV radiation.
The most important criterion for proper penetration is the appropriate choice of penetration coating. It must always chemically match the selected surface treatment. Manufacturers usually offer a specific penetration coating for a specific product.
- Before application, the paint must be thoroughly mixed (with a stirrer)
- Prefer mechanical suction before spraying. The brush and roller are more suitable because they facilitate the penetration of the substrate by their mechanical action.
- The dilution ratios given by the manufacturer must always be observed when diluting.
- The coating is applied evenly, by the recommended method. Apply only as much as the substrate is able to soak. If a larger amount of paint is applied, shiny surfaces can be created which in turn deteriorate the adhesion of the next coat (colouring problems arise with silicate technologies).
- Penetration coatings are usually applied in several layers. It is not advisable to delay application of another layer, because when the coating dries completely, mixing of both layers is problematic.
- The penetration must be completely absorbed into the substrate after application. If a puddle is formed, it is necessary to spread it into the surface.
When applying penetration coatings we use paint brushes, rollers or spray guns. We also use ladders, scaffolding or forklift trucks. To maintain the colour shade we also need machine stirrers. Before applying the penetration, thoroughly prepare the substrate. The substrate must be clean, dry, solid, free of dust, grease and oil. In the case of concrete coating, it must be matured, free of mechanical impurities. In the event that there are cracks on the surface, they must be sealed with epoxy mastic. The substrate must be insulated because rising damp could breach adhesion (peeling).
Before applying the penetration coating on the wooden surface, the wood must be sanded, cleaned, and any unevenness repaired with suitable wood fillers. Apply a primer that penetrates the depth of the material to be treated with the wood structure. The number of applied layers is chosen according to the desired final effect. The use, composition, colour, method of application, dilution, properties and safety at work must be stated by each manufacturer in the product data sheet.
|How to with penetration coatings? http://www.naseinfo.cz/. [online]. 11.10.2016 [cit. 11/10/2016]. Available from: http://www.naseinfo.cz/stavby-a-stavebnictvi/uprava-povrchu/jine-upravy/jak-na-penetracni-natery|