To fully understand just why high-solids paints are the best choice to make, it is important to know the components of an average paint. As described in this blog, paints are made up of a mixture of solids and liquids, different amounts of each giving different finishes.
The liquids in a paint are solvents. These change the flow of the coating material and allows for a smoother application. For example, water is a solvent for sugar. In most paints, the solvent does not dissolve the solid but dilutes or thins it.
The solids come in three different forms: Binders, Pigments, and Additives.
The Binder is the main ingredient of paints. Binders are polymers forming a continuous film on the substrate surface.
They provide good adhesion of the coating to the substrate. The binder holds the pigment particles distributed throughout the coating.
The Pigment, to no surprise, provides the paint’s colour and opacity. However as well as this, they can also have the job of protecting the paint from UV light.
Additives are included in paints to modify or change the paint’s properties. For example, matting agents are added to give the paint a more matt finish, and wetting agents are added to make the product flow better.
Paints are often rated by the amounts of solids within them. There are low solids, medium solids, and high solids. There aren’t any official guidelines to dictate one category from the other, however, the typical guide is as follows:
Low solids are roughly up to 30%, Medium is 30% – 60%, and High is anything above 60%.
So by knowing this, it is not only clearer as to why high-solids paints are brighter and more opaque (less of the paint evaporates whilst drying), but it becomes clear that high-solids paints will go a lot further.
The higher the percentage of solids within a paint, the lower the solvent content, and therefore the further the paint will go. As explained in this great blog: A paint with 60% volume solids will cover 12m2 per litre at 50 microns dry film thickness, while a paint with 40% volume solids will cover only 8m2.