Paint Technology - Exterior Finish Education

Clearcoat Clarification
HPP: Has clear topcoat technology changed along with basecoats?
RS: There have been some major advances in clear technology. Before, hobbyists had to wait several weeks for a vehicle's clear topcoat to cure before waxing, but cross-linking technology with basecoats has introduced clears that cure quicker, which means they can be waxed sooner. PPG has recently released a new ultra-clear product, and while it costs more than a traditional clear, it's crystal clear, and makes the basecoat look more vibrant. There's also a Soft Touch clear that gives the sensation of powder when running your fingers over it.

A new product that's being used by high-end auto manufacturers is ceramic clear. It's expensive, but very resilient to swirling and scratching. Testing has shown that after hundreds of cycles through a simulated car wash, the bristles caused typical clear to cloud, but the ceramic clear remained brilliant. It's difficult to apply, and must be smoothed within a day or two of application, but ceramic clear does offer improved finish protection.

Waterborne Wonderings
HPP: Are there any government regulations that are playing a role in current paint trends?
RS: Definitely. California is known for its stringent air-quality requirements, and in 2005 it placed strict limits on the amount of VOC that can be emitted when applying a multi-stage finish. Modern waterborne basecoats were introduced and have significantly lowered VOC emissions. Many areas in California already require its use by the end of 2008. I feel it's only a matter of time before other states follow suit. In fact, we're already seeing local collision repair shops inquiring about the conversion process.

HPP: Pontiac used waterborne paints in a few of its assembly plants in the '70s and the finishes didn't age well. Should this be an area of concern for hobbyists today?
RS: No, not at all. PPG is a waterborne-paint technology pioneer, and today's product is far superior to what it was then. Waterborne paint actually contains many positive attributes when compared to solvent-based paint, but only the basecoat is presently waterborne-the primer and clearcoats remain solvent-based. Those products, too, will likely become waterborne in future years, but technology hasn't required that yet.

HPP: Can you elaborate on how waterborne basecoat differs from a similar solvent-based product?
RS: The application process of the two types is definitely different, and shops must train their technicians on the proper technique of using waterborne products. Unlike solvent-based paints that require somewhat lengthy drying times or moderate heat to bake out solvents before applying additional coats, waterborne paint requires different equipment to achieve fast flash and cure times, but it isn't as temperamental to air temperature and humidity levels within a paint booth.

Also unlike solvent-based paint, waterborne products contain nonsettling technology-the metallic stays in suspension and doesn't settle to the bottom of the container, which means that agitation isn't required when in the mixing room. Before pouring the paint into the gun, simply tilt the bottle back and forth a few times, and it's ready for use. This makes it far more favorable for color-match repairs too.

HPP: What type of unique equipment is required when applying waterborne paint?
RS: Waterborne paint requires extremely high-quality pressurized air with large-volume inline-driers. Paint guns dedicated for waterborne products are also required-water can corrode a typical gun with aluminum passages, so those designed for use with waterborne products feature plastic or stainless steel internal passages. The gun tip when using waterborne paint is also smaller.