Idaho-based Nestegg Trailers uses VOC-free fiberglass alternative

Manufacturers have long used fiberglass when a strong, lightweight, formable material with some flexibility is required, but the resins used in its manufacture emit hazardous volatile organic compounds (VOCs). Resins serve as a binding agent to fiberglass strands and typically contain styrene, a toxic air pollutant. Fiberglass is increasingly regulated by federal, state, and local agencies, particularly in California. “We have manufactured composite fiberglass trailers with traditional polyester resins, vacuum infusion, even epoxies, but after California’s Air Quality Management District (AQMD) levied a $26,000 fine for VOC emissions, we moved out of state,” says Vince Austin, owner of NestEgg Trailers, a manufacturer of lightweight tow-behind trailers now based in Hayden, Idaho.

Fines and regulatory headaches have many traditional fiberglass users looking for VOC-free materials, leading to the development of polyurea, a resin substitute that dries within 30 seconds and can be used with a chopper-mounted spray gun to make parts, molds, and rapid prototypes in minutes.

Fiberglass emissions

When NestEgg started, Austin says employees hand-layed traditional polyester resins into a fiberglass matrix, but he found that labor-intensive technique only worked when his company was very small.

“As we got busier, we had to change because we were emitting too many VOCs with higher production,” Austin says.

NestEgg Trailers next tried the vacuum infusion process of creating fiberglass with polyester resin. A sealed bag had to be placed around each part for the vacuum infusion process to contain and remove the VOCs.

According to Austin, “After we did a couple of trailers that way, we realized no one would be able to afford the labor involved as well as the large amount of bag and sealer waste.”

The next attempt was using epoxy as a fiberglass-binding agent to lower its VOCs.

“The problem was that epoxy is very costly, all hand laid, and cannot be sprayed on a fiberglass chop machine, so it was cost- and labor-prohibitive,” Austin says.

Using polyurea

After extensive research into new fiberglass options, Austin decided to try AroStruct, a no-VOC, fast-set, rapid-cure, structural polyurea created by VersaFlex. Choppers cut fiberglass strands to the desired length and throw them in front of the polyurea resin. The resin attaches to the chopped fiberglass and lays into the mold of the fiberglass part being manufactured.

Unlike toxic polyester resins that can take up to a day to fully cure, the spray-applied structural polyurea applies with 100% solids, dries within 30 seconds, and cures within 60 minutes.

“Compared to traditional fiberglass part making methods, I’ve lowered my labor cost by 50% and mold making cost by 75% with AroStruct,” Austin says.

Spraying is achieved with a plural component spray gun connected to a long heated hose and pump machine. Unlike epoxy, which has a short pot life, the structural polyurea’s components are mixed in the spray gun nozzle during application so pre-mixing is unnecessary and there is no waste in the process.

High strength

The polyurea product is also waterproof and exhibits hardness, high elongation, and tensile strength.

“We’ve found AroStruct to be at least as strong and flexible as traditional resins, but without the VOCs, so we can spray indoors or out and meet regulations,” Austin says. “We were looking for the right combination of strength and elongation, and VersaFlex worked with us to optimize the formula for our process.”

The structural polyurea enhances the structural integrity of substrates that it is sprayed on, and can be painted.

“When our off-road trailers need extra strength, we spray the structural polyurea on their underside so running over rocks won’t hurt them,” Austin says.

To boost productivity, Austin mounted a fiberglass chopper on the spray gun.

“Since the structural polyurea is so easy to apply with the spray-gun-mounted chopper and dries so quickly, we’re making product in about one-tenth the time,” Austin says. “It lays down nice so there is no need to have guys rolling the product out to get the air bubbles out.”

NestEgg Trailers now uses the structural polyurea in about 75% of its fiberglass part making processes, with the goal of fully transitioning from polyester resins as soon as possible. In addition to trailers, the process could also be used for fiberglass automotive parts, truck bodies, and powered vehicles.

“Our fiberglass part-making efficiency has improved so much that I’ve moved half of my crew from making fiberglass parts into assembly,” Austin says. “That not only boosts production but also lowers our cost per part, making us more competitive.”

Faster mold making

According to Austin, one of the greatest benefits of switching to the structural polyurea is how it expedites the process of making molds for parts.

“The traditional mold making process, using polyester or epoxy resins, is very costly and labor intensive,” Austin says. “It can take weeks to hand lay the fiberglass.”

Instead, NestEgg Trailers uses structural polyurea for rapid prototyping of new designs or to create production molds. According to Austin, he used his vendor’s powder-coated steel fender as the mold’s plug, or mold master part.

“We simply waxed the part, put clay in any pockets or holes, then sprayed the fender with just the structural polyurea. When that dried within 30 seconds, we peeled the piece off the painted fender surface and had our mold. While more complex molds still require a cage around the part, we can make a mold in about one to two days that would typically take one to two months using traditional resin,” Austin concludes.

NestEgg Trailers

www.nesteggtrailers.com

VersaFlex Inc.

www.versaflex.com