At Winona Powder Coating, "Quality From Start to Finish" is more than just a catchphrase. It’s our company’s philosophy, the modus operandi that guides all of our internal processes. From first pretreatment to finished product, from project onboarding to final delivery, every member of the Winona team strives for precision results.
When you’ve been in the powder coating business since 1974, you learn that quality isn’t just a checkbox, but a daily commitment that lives through every person on your team. Our quality control process is carefully orchestrated not just to meet industry standards and certification requirements, but to establish a true culture of quality that underlies all of our day-to-day operations.
Our quality team isn’t sitting in an office or off-site reviewing reports. Typically they’re on the floor, hands-on, involved in every stage of the coating process. From the moment parts arrive at either our 167,000-square-foot facility in Etna Green or our 50,000-square-foot facility in Elkhart, you’ll find our quality experts working alongside our production staff to ensure every component meets or exceeds the exacting standards that our customers trust us to meet.
Step inside one of our state-of-the-art facilities and see some of the unique steps we take to ensure your products are finished to each customer’s exact specifications:
Many smaller powder coaters might only perform visual inspections, while more advanced shops will typically add thickness and adhesion testing to their process. But at Winona, we take it a huge step further: our team conducts a total of six comprehensive quality tests on every batch. Far beyond basic inspection, these are scientifically validated procedures that catch a number of quality issues you can’t even see.
It’s one thing to ship powder coated parts that look great straight out of the shop; it’s another task altogether to ensure every coat is durable, delivering long-lasting aesthetics and functional protection.
A powder coating is only as good as its cure. That’s why our quality team is meticulous with our curing ovens. Convection ovens are the most complex cure systems in the industry, requiring constant attention to burners, blowers, ductwork, and dozens of moving parts.
Our maintenance schedule is rigorous, with regular detailed inspection of all equipment. Far more detailed maintenance procedures are performed monthly and annually. Essentially, proper oven maintenance can be the difference between a coating that lasts decades and one that fails within months.
After curing, we measure the dry film thickness on every production run using calibrated gauges. Depending on the application, our inspectors are typically looking for 2 to 4 mils of coverage, or 0.002” to 0.004” in thickness. Too thin and you may miss complete coverage. Too thick and you’re not only wasting material, you’re also potentially compromising coating flexibility and adhesion.
Our quality technicians use digital coating thickness gauges that measure with precision tolerances, typically invisible to the eye. They take multiple readings across each part, calculating averages, identifying highs and lows, and ensuring we’re consistently within specification. These readings are documented, tracked, and become part of each job’s permanent quality record.
We test adhesion by using a specialized crosshatch cutter to score a grid pattern through the coating down to the base metal, creating a lattice of small squares. Then we apply pressure-sensitive tape over the grid, smooth it down firmly, wait 60 seconds for recovery, then yank it off at a 180-degree angle.
An acceptable result shows only minimal coating removal from the edges of the cuts. If entire squares lift off, adhesion is suspect. If the coating comes off in sheets, it’s an adhesion failure.
One of powder coating’s greatest advantages is the beautiful finish it produces. But maintaining that appearance requires vigilance. Our quality inspectors examine every production run for gaps in coverage, bubbles, warping, contamination, and poor application.
Contamination is the usual culprit when appearance issues arise. Shop dirt, welding debris, sanding dust…basically any airborne contaminant can cause the powder to react negatively or fail to cover properly. That’s why our pretreatment process is so crucial. Improper cleaning, poorly mixed chemicals, or inadequate rust removal will show up as finish problems.
Every customer is different. Some have strict automotive manufacturing specifications. Others have highly specific architectural coating requirements. Others projects may call for industrial durability, others products demand premium aesthetics and branding for the consumer market…. That’s why a major part of our appearance testing involves detailed communication with each customer about their specific criteria.
An acceptable finish might be defined as no more than two visible surface imperfections per square foot. Or it might include specific gloss and color tolerances. It all depends on the customer. But basically, whenever there are exact requirements, we make certain they are met. Our quality team maintains documentation for each customer’s standards, and they reference these specifications while performing careful, highly detailed visual inspections for every run.
From our industry-standard ISO 9001-2015 quality control process to our numerous AAMA approvals, Winona is backed by a long list of quality guarantees.
Preferred Agricultural Supplier, Approved for the Following:
Other Certifications and Approvals:
At Winona, we believe that when a company commits to its customers, actively grows its problem-solving skills and quality assurance, while simultaneously keeping pace with new advancements in coating technology, success is inevitable.