The solids content of a paint is crucial because it directly determines the thickness and durability of the final coating after drying.
The higher the solids content:
- Less material evaporates into the air, meaning a larger portion of the applied product remains on the surface.
- Durability and weather resistance are generally superior.
For solvent-based paints—for example, those with 40% solids—60% of the product evaporates, leaving 40% on the surface.
For solvent-free linseed oil paints or stains, the solids content can reach 95–100%.
Solids content is not the only indicator of quality. Other factors are also important, so I will highlight the advantages of linseed oil coatings:
- Type of binder – linseed oil, a natural moisture-repellent coating.
- Pigment quality – mineral pigments offering high protection against UV radiation.
- Flexibility – upon drying, the oil forms a flexible coating that does not crack as the wood’s dimensions change (through shrinking or expanding).
- Vapor permeability – linseed oil coatings are vapor-permeable, ensuring the wood remains in good condition over the long term.
- Adhesion to the substrate – linseed oil paint adheres excellently to virtually any surface; only the drying times vary.
The high solids content of linseed oil paint is particularly valuable because, upon polymerizing, the linseed oil forms a dense protective layer that penetrates the wood well and ensures long-lasting protection. Since the oil soaks deep into the wood, protection is provided both on the surface and within the wood fibers themselves. Linseed oil typically penetrates deeper into the wood than many paints or varnishes.
Because linseed oil paint does not crack or peel, such surfaces are very easy to refurbish—a highly important factor.