Powder coating has long been a staple in metal finishing operations but it isn’t until fairly recently that it has started to make inroads in the woodworking industry. According to one expert in the process, woodworkers should embrace the process for its efficiency, quality, and low environmental impact.
Chris Reding, global director for alternative substrates at IFS Coatings spoke with the Woodworking Network Podcast at length about powder coating for wood. His background includes working in the powder coating industry since 1996. Today he specializes in non-metal applications for the technology, including on wood and engineered wood substrates. To hear the entire recording, go to woodworkingnetwork.com/podcasts. Here’s a summary of what he said.
What is powder coating?
While most woodworkers are familiar with traditional woodworking finishes that are typically liquids applied with spray equipment, brushes or even rubbed on by hand, powder coating is a different process entirely.
“Powder is electrostatically applied,” says Reding, explaining the process. “We have a gun called a corona gun that pneumatically conveys the powder through hoses from a hopper. As it exits this gun, it goes through a corona field, which is a big charge of negative ions. The powder picks up that charge. We use the moisture content of the wood as a conductive means to ground it. So, that charged powder is electrostatically drawn to that grounded workpiece.”
To equalize moisture content so the ground is even throughout the substrate, in most cases the substrate is heated to about 120 degrees Fahrenheit. The pre-heating is often not necessary with hardwoods, but is important with engineered wood.
After the powder is electrostatically applied, the workpiece is put into an infrared oven where the temperature of the powder goes up to about 265 degrees F for about four minutes. That gives a homogenous, fully cured finish that went from raw substrate to cured finish in about seven minutes.
“Our solvent is air,” said Reding. “We have 100 percent solids. We’ll melt and flow in the initial stage and then when we hit the cure temperature there will be all the cross-linking, and it happens really quickly.”
Early adopters in Europe
In the woodworking industry, the early adopters of powder coating tend to be in Europe. First applications were on kitchen cabinets and then in ready-to-assemble furniture.
“Without naming names,” said Reding, “the biggest RTA manufacturer on the planet adopted powder for bathroom vanities and daybeds. They’re putting out about 9,000 units a day.”
As the technology improves, Reding says, so has the surface finish and the variety of finishes available. He says the sheen and smoothness of powder coating easily competes with quality thermofoil finishes, but it does not reach the ultra-high gloss level of some modern finishes especially popular in Europe.
Still, powder can help manufacturers achieve those ultra glossy finishes faster, Reding says, by using powder as the primer coat. Applied in the same process as described earlier, the sandable primer powder can reach maximum opacity very quickly.
“Just as a test last week with my customer in their facility, I got a can of safety yellow, which is about as tough a scenario as I can think of to get opacity, and we put on the primer in one coat,” said Reding. “So, there’s an opportunity if we demand that liquid finish, we can still help a lot in terms of speeding up your process.”
In contrast to conventional finishing, Reding says powder is relatively easy to get into both in equipment and training.
“Equipment investment is pretty conservative,” he said. “We can start off somebody quite small. One section of oven and one gun, and basically you’re ready to go into business.”
He maintains the learning curve for applying powder coat finishes is much less than training skilled finishers.
“Applying powder is considerably easier,” he said. “I can spend a couple hours with just about anyone and have them produce a pretty decent looking powder coating whereas with a liquid finisher, this is a pretty deep skill set.”
He does add, “You need one really smart person who understands the equipment and knows how to the setups and all that.”
Once the system is in place, manufacturers can reap huge efficiency gains. “Finishing is the bottleneck for many operations, and we change that,” he said, noting that complex finishing can be reduced to minutes.
Unlike liquid finishes, powder is 100 percent solids. That means no volatile organic compounds (VOCs) or other toxic chemicals to worry about.
“There’s no solvents at all. No smell,” he said.
Typically liquid paint is up to 70 percent solvents, he said.
New looks, colors
Reding says there is a huge variety of finishes available, including some finishes and textures that aren’t often found on wood.
“Hammer tones, river finishes, speckles, (on metal) we can do these on wood as well,” he said. “Dimples, multi-color finishes, the pallet is pretty much endless.” He says IFS Coatings currently has about 70,000 color formulas available.
And while traditional powder coating is often seen as an opaque finish, it also can be done as a clear or translucent application. For example, tinted clear powder can be applied over a hardwood such as maple to have a similar effect as staining. He showed samples such as maple with a cherry tint and oak plywood.
Anti-microbial properties can also be part of the powder coating formula, he said. And there is a “super durable” powder formula for exterior wood finishing.
“The coolest thing about powder for me and it makes it kind of a mission,” Reding says, “is we’ve got the safest coating technology out there with the best environmental footprint, and we deliver a better finish a whole lot faster.”
You can learn more about powder coating on wood at https://www.ifscoatings.com/content/markets/powder-for-wood
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