Painting over PVF2 Cladding
PVF2 Fluorocarbon is a wet paint system developed for coating aluminium and painting over PVF2 cladding is a common practice both for restoration or simply to change the colour. Part of this type of overlay is PVDF which is an acrylic resin. It stands for Polyvinylidene Fluoride and it is a thermoplastic fluoropolymer. 1965 saw the development of fluoropolymer, an advanced architectural finish that was superior to the polyester coatings at the time.
Essentially, liquid paint consists of resin and pigment which are both solid. The role of the pigment is to provide the colour in the finish and to cover whatever is underneath such as a primer or the substrate itself. On the other hand, the resin (in this case acrylic PVDF) is the glue that sticks the particles of pigment onto the surface.
For these chemicals to become a paint system (PVF2), the solid particles of the pigment and resin have to be dispersed into a liquid for ease of application and this is achieved by adding a solvent to the mixture. Essentially, the solvent enables the solids to be applied on to the substrate. Because there are solvents and VOC’s in PVF2 it is not as environmentally friendly as a Fluoropolymer powdercoating system and there are health risks for the applicator and the public. However, the system is used extensively because it hard wearing.
The PVDF resin does not degrade quickly, partly because it is not easily affected by UV light, so it is highly resistant to fading and chalking. Furthermore, it guards against pollutants, salt (for buildings by the sea) and acids for longer than many other top layers. In fact PVF2 is said to perform better than polyester powder coatings and anodizing.
One of the other advantages of PVF2 is that it is easy to clean, but if this coating on an industrial building is not cleaned regularly the layer can degrade faster than usual. Deposits need to be removed from the surface and parts of metalwork that are not washed down mechanically or by rainfall do tend to deteriorate more quickly than those areas that are rinsed. Vulnerable features are typically sheltered roofs and cladding on elevations. Airborne pollutants should also be brushed and washed off at least every six months as contaminants can cause damage.
Another possible area of deterioration is around fastenings on cladding. Oversized holes with the correct washers are necessary for the natural expansion and contraction of metal in order to prevent crevice corrosion. Corrosion can also set in if cut edges are not sealed properly, but a good on site paint spraying company will be able to carry out minor repairs including cut edge corrosion.
Even if a property is maintained properly, any covering on metal will deteriorate after a certain length of time, so a re-spray is a way of restoring cladding or other metalwork. This isn’t the only reason as sometimes a straightforward colour change is called for if the lease on a property has changed hands or a business is rebranding.
Whatever the reason for re-painting, good finish is sought after by companies because it is well known that aesthetics play an important role in how well a business of thought of. Furthermore, if painting over PVF2 is done professionally, the cladding or other type of architectural metal will last many more years thus reducing the need for replacement.
Repairing metal previously coated in PVF2 is not only cheaper than replacement, is also a faster solution. Spraying a new coating is also less time consuming than brushing or rolling paint on and the finish is far smoother. Experienced on-site sprayers will suggest the most appropriate coating and method of painting over PVF2 cladding and the finish should be as good as new.