Precision Coating for the Military

Article From: Products Finishing, , from Sherwin-Williams Co

Posted on: 7/1/2001

Coatings are extremely important to the military because of the critical applications military equipment is used in. Thanks to a new CARC coating, Pribbs Steel has no problem meeting the military's demanding standards...

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Coatings are extremely important

Coatings are extremely important to the military because when a paint failure occurs, the paint usually falls off in big chunks. But Pribbs Steel has won the military's confidence with the quality of its paint job on these M105A3 trailers.

high in solids and very dense

Because CARC coatings are high in solids and very dense, they are not easy to apply. But chemists were able to adjust the viscosity of the paint used by Pribbs Steel to prevent sags in a coating that would be 7-10 mils.

Try this specification on for size:

Design, manufacture and paint a steel trailer that can bear a 6,000-lb load. The trailer will be lifted by a helicopter and must withstand the force of a 3g turn in the air while loaded. The trailer must be safely and easily accessible from the ground. It must roll easily at highway speeds; yet maintain an upright position when driven at such speeds over an 18-inch bump. And, it must bear a predetermined camouflage design, specific to the half-inch, applied with coatings that will withstand environments ranging from ocean salt to desert heat to jungle swamp to Arctic cold.

That's just page one, paraphrased, of course. There could be up to 100 pages to go in the business of defense contracting.

According to Tim Pribula, the CEO and president of Pribbs Steel and Mfg. (Grand Forks, ND), success in military contracting is a matter of taking such specifications and achieving perfection repeatedly and consistently. "We have no room for error," said Mr. Pribula. "The detail in all of our production and painting processes is very tightly controlled. I'm a perfectionist, but you have to be for this type of work. In a military combat situation, lives depend on equipment and coatings that work."

On the Farm

Pribbs Steel was born in 1979 when the innovative farm equipment designed by brothers Arnie and Ernest Pribula began attracting a local market. As the farm economy suffered, the Pribulas looked for other means to employ their mechanical and design skills and attended a seminar on military contracting.

The military was seeking new suppliers at the time, and the Pribulas gained their first military contract in 1984 when they manufactured a truck's battery box. The firm gained more complex contracts and grew slowly, developing a reputation for the quality demanded by military organizations.

Meanwhile, younger brother Tim Pribula was busy gaining a degree in mechanical engineering. Tim joined the firm in 1989, and the older brothers phased into retirement. Under Tim, the firm has tripled in volume and recently moved its 50-plus employees into a new 55,000-sq-ft facility on the outskirts of Grand Forks.

The previously described trailer-known as the M105A3-makes up about 60% of the plant's output at present. Contracted with the Army's Light Tactical Vehicle Division, the five-year agreement calls for the production of a possible 5,000 trailers and is significantly longer than a standard military contract, testimony to the faith the military has developed in the company's work. Mr. Pribula typically supplements such big jobs with smaller contracts for other military branches to keep his workforce active. These contracts tend to focus on parts for repair and replacement, such as vehicle splash guards, jacks and fenders.

Mr. Pribula is a hands-on manager and has a working knowledge of the state-of-the-art production equipment used to build these units. This equipment includes two Rofin-Sinar laser steel cutting systems, a robotic welder and several manual welding stations. While Mr. Pribula keeps a watchful eye on production, no process receives as much scrutiny as the painting process. "Paint is one of the biggest problem areas the military has," stated Mr. Pribula. "Failures in paint are very noticeable because when one occurs, the paint just falls off in large pieces. The result is degradation of the product."

Undercoating Focus

Paint has played a key role in the brief history of the M105A3. Pribbs Steel has already been producing the trailer for one of the contract's five years, but the military had been experiencing coating failures on the under side of similar trailers made by other suppliers and was looking for a solution.

Working closely with its coatings' supplier, Mr. Pribula began zeroing in on an undercoating formulation that, based on strictly controlled application circumstances, would meet the military's requirements for protection and, most importantly, adhesion.

Mr. Pribula soon was exposed to the wide-ranging resources available from his new partner, Sherwin-Williams. First he teamed with the paint supplier to adjust the viscosity of the undercoating until it could withstand the most rugged
duty the Army could dish out.

Application was another matter, however, as the product was high in solids and dense. Chemists adjusted the viscosity of the coating to eliminate sags in a coating that would go on at 7-10 mils and would adhere under any circumstance. But the undercoating was a challenge to apply since its high-solids formulation resulted in a pot life of just 2 min. To accommodate the short pot life, the two companies modified a mixing unit and came up with an application system that allowed the paint to be applied within its limited pot life.

The undercoating is used extensively on the chassis and cargo box of the M105A3. The rest of the galvanized construction of the trailer, as well as most products that come off the Pribbs Steel production line, bear a Sherwin-Williams epoxy primer applied at 1.8-2.0 mils. The topcoat is a chemical agent resistant coating (CARC) specially developed for the military.

Besides the adhesion and low sheen requirements put forth by the military, CARCs also perform several critical defense functions. First, the coatings are not detectable by infrared detection systems. Second, in the case of chemical warfare, CARCs can be chemically decontaminated.

Also, CARCs can have challenging application characteristics. And camouflage patterns designed by the army demand that tan, brown and black topcoats overlap areas of green at precise points. Mr. Pribula, however, has established a working environment that nurtures consistency and precision. "What we're trying to create here is an environment where people want to work. I think that has a carryover effect onto the quality of the work people perform," said Mr. Pribula. "But it's not just a morale issue or a safety issue. A particle of dust can change adhesion. That's why we have a very carefully controlled environment here."

Manual Application

Despite some production tasks that are automated at Pribbs Steel, painting remains a manual operation since Mr. Pribula feels a properly trained and motivated painter can control quality more effectively than a machine. Applicators work out of two downdraft booths and use an infrared bake oven for curing.

"The key to success in painting is once you do it successfully, you have to consistently repeat the process, and it all starts with a good surface," Mr. Pribula explained. "You need the right substrate with no materials that will interfere with adhesion. Galvanized has to age properly in order to assure adhesion. We store it indoors in small bundles and blow fans across it to keep condensation and humidity off.

"We keep the climate controlled. We buffer down all welds and recoat them with zinc. We inspect our washing procedure and regularly measure the titrations of chemicals. We use an infrared bake oven to accelerate the dry time, creating more links in the molecular structure of the coating. Some of our products will go through two to four bake cycles. And we use low batch quantities to ensure consistency. Product consistency is extremely important to us."

Mr. Pribula's customers would agree on that point. "Defense contracting not only demands quality, it demands repeated quality," Mr. Pribula added. "They've discovered that with the coatings we've engineered with our paint supplier and with our strictly controlled application procedures, we can deliver such consistency."

 

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