Volume 48, Issue 12- December 2013
Inorganic Vs. Organic: Which Coating is Right for Your Project?
Coatings provide glass with many of its more exciting characteristics, so performance is a matter of picking and choosing desired characteristics rather than getting it all.
Coatings generally are either organic or inorganic. But what, exactly, does that mean?
According to Jeff Nixon, general manager of Glass Coatings and Concepts in Monroe, Ohio, “Organic coatings are based on carbon-based molecules, as opposed to inorganic coatings, which are based on inorganic molecules. Inorganic molecules tend to be very tough and resistant to things such as heat or chemical attacks or other environmental factors. Organic molecules tend to be more flexible and you can do more with them—but they typically don’t last as long as inorganic coatings, or withstand high temperatures or attack by acids or solvents,” he says.
To break it down further from an application standpoint, “It comes down to temperature,” says Kris Vockler, CEO of ICD High Performance Coatings in Vancouver, Wash. “Prolonged temperatures of around 500 degrees Fahrenheit will start to yellow or burn up organic coatings or, rather, the carbon in the chemistry.” The higher the temperature, the faster the yellowing, she notes.
“Just like they used to say ‘never buy a red car, they tend to fade,’ organic coatings tend to be susceptible to that long-term exposure to light or water or chemicals,” Nixon says.
However, Vockler says organic coatings offer a vast array of color availability. Their comparative lack of durability “may or may not be an issue, depending on the coating,” she says.
On the other hand, inorganic coatings are made to last, Nixon says. “They tend to look exactly as they did day one for decades to come. The disadvantage tends to be you have to fire them on—and that’s not always a disadvantage since you have to fire heat-treated glass anyway. But they’re not applied post-firing and there are some limitations around what the chemistry can do, mostly around color.”
Vockler adds that while inorganic coatings can be more chemical-resistant, they often must use heavy metals as a base for pigments.
“It’s a trade off,” Nixon agrees. “One might use either one depending on which properties are of the greatest interest.”
Both coating types seem to be enjoying popularity for a variety of applications.
“What we’ve seen is there has been a move toward [inorganic] ceramic enamels because they’re easy to use, they’re really hard—meaning you can’t scratch or damage them during installation or in service—and they really do last forever. That being said, there are some people who like to use the organic paints, especially in interior applications where highly saturated colors are desired and long-term performance is less critical,” Nixon says.
“Organic coatings have seen a huge surge in the last five to 10 years,” Vockler says. “It’s becoming rather equal in the marketplace, I think.” However, she is quick to point out that, in the end, it comes down to the application. —Megan Headley