So what is the big deal about waterborne paint? This was the question that I asked myself when water borne paint first started being discussed. There have been a lot of changes in the way people perceive waterborne, but the reason for the switch remains the same, which is VOC (volatile organic compound.)
Most base coats (the color) do not contain a catalyst. The catalyst is what contains the isocyanates, which is the hazardous material that causes many health problems. Therefore, why switch to waterborne, if the base coat does not contain isocyanates? The base coat is the only product with the big push. I think that PPG is working on primers and clears, but as of now, they are going to continue to be solvent based in the US.
I am not sure about every brand of paint, but PPGs base coat reduces 1:1, which is 100%. This means that at least half of the material that you spray onto the surface is going to evaporate. The material that evaporates is the VOCs and that is what the EPA is concerned about.
Primers and clears are catalyzed, but they are high solids. Most primer surfacers and clear coats are not reduced, which results in less solvent resulting in less VOCs. More of the high solid products stay on the surface being sprayed. With this in mind, I now understand their point-of-view and why paint companies are targeting the base coat first. To lower VOCs!
We’ve recently switch to using waterborne at Butler Community College to take another step towards green and to provide a safer cleaner working environment for our students. It is a little different. It requires a 75% overlap as opposed to the solvent 50% overlap. The paint will also scare you at first because the paint changes all different colors after sprayed. About the time you think the color is not going to match, it dries to the correct color. Other than that, we have not come across any unusual problems.
Check back as we will continue to write more about waterborne paint and share our results with you.