The alternatives to solvent-based paints.
Waterborne paint has become the standard, as 70 percent of all OEM vehicles are now painted with this material. It has been the standard in Europe for a long time, so while the latest waterborne paints are new technology, the concept is neither new nor experimental. In many cases, however, solvent-based paints can be altered to achieve compliance through the addition of other chemicals such as KV1, which is added to Valspar solvent-based paints to lower the dreaded VOC.
Waterborne paint is exactly what the name implies. Solvent-based paints use solvent to suspend the paint pigments and deliver them to the surface to be covered, while waterborne paints use water.
While the biggest initial concern with waterborne paint was the availability of colors, the paint makers have released a significant line of colors for the custom builder. Metallic paints and color-matching have improved with the technology.
Nearly all waterborne paints use a two-step process-basecoat color covered by a clearcoat. The final surface prep for waterborne paint is similar to older paint: wet-sanding through several different layers of clearcoat with varying grits of paper and then final buffing. Early stages include spraying primer in the standard fashion with solvent-based materials and then a sealer coat that is determined by the choice of base color paint. If there is any question, there are plenty of color guides available depending on the paint you select.
An advantage to waterborne paint is it delivers better coverage in fewer coats. Where it would take three to four coats to cover a panel with solvent-based paint, it will only take one to two coats with waterborne, using less material overall. One thing to note is that only the base color coat of the paint system is waterborne; all other layers, including the clearcoat, are still solvent based and sprayed in the normal way. The days of 26 layers of hand-rubbed lacquer are way over-but then again that was always more about bragging rights than quality.
Waterborne paint does not smell as caustic as solvent-based paint, but that does not mean you can spray without protective gear. In fact, just the opposite is true. Despite reduced VOC levels, waterborne paints feature plenty of chemicals that are deadly to humans. A respirator is necessary at all times. In addition, because of slow drying times, the paint lingers in the air longer.
Pros of using Waterbourne paints include:
- Delivers better coverage in fewer coats due to its higher pigment content
- Reduced mil thickness when dry, which reduces paint pulls when bolting down other body components, such as side mirrors.
- Improved metallic lay-down on body surface.
- Reduced gassing out over time-once the basecoat is dry, it is final. Solvents release gas for several months after application, which can affect long-term paint finish.
Cons of using Waterbourne paints include:
- Harder to shoot as it requires a different spray gun and dryers.
- Flash time is critical-it takes longer to dry overall.
- Higher material cost-paints and ancillary products.
- Blending of painted panels is harder, requiring you to learn a new skill set.
- Not a task for home application-a spray booth is required because of slow dry times.