Synthetic veils provide better corrosion resistance with severe pH chemicals such as hydrofluoric acid, sodium hypochlorite and many others, he adds. They also work very well in any composite that is subjected to UV radiation.

Printed veil fabrics can provide graphic characteristics, such as a wood grain or camouflage look. Colored veils enable manufacturers to produce variations of their products without having to completely change over a line.

As with gel coats, a manufacturer’s decision on whether or not to use a veil often comes down to cost. “A lot of it is solving the problem for the right price,” Ratcliffe says. “Imparting improved UV protection is a complex problem to solve and often requires a solution that is more than just a basic veil fabric. You have to put a coating on the veil that incorporates different UV absorbers or antioxidants to improve UV protection. The same is true for improved flame and smoke mitigation.”

Customers are looking for better solutions that they can integrate into their manufacturing processes in one step, Ratcliffe adds. When deciding between veils, gel coats, in-mold coatings and post-paint processes, manufacturers typically consider total cost of the materials, processing cost and manufacturing scrap rates to determine the best way to proceed for their specific solution.

Measured Advances

Progress in surface materials comes incrementally – an improvement in a gel coat’s resin can enhance durability, a new type of fabric can offer better corrosion resistance. But those changes make a real difference over time. One of Ashland’s earliest marina gel coats had an expected lifetime of 1,000 hours; its latest generation of products can reach 4,000 to 4,500 hours.

While gel coat manufacturers are reluctant to give specifics about the new products their companies are working on, they will discuss the industry’s direction in general terms.

wind-turbine-from-polynt-composites

Gel coats designed for wind turbine blades provide added protection against abrasion, fatigue, heat, light and moisture. Photo credit: Polynt

“The main drivers of change related to the performance of composite surface finishes include the performance in the field (for example, weathering, water resistance, etc.), economics and environmental/safety issues,” Crump says. One environmental driver has been reduction of the amount of styrene used to make gel coats; manufacturers had to redesign their formulas to get the same properties they had previously offered in higher styrene-content formulas. Regulators are likely to continue the push toward lower styrene content and lower VOC materials in general.