Technology Interchange—Flame On

By Troy Newport

The thermal spraying process, also known as flame spraying, was developed around 1910 by Swiss engineer Dr. Max Ulrich Schoop for corrosion protection and machinery restoration. The primary coverage materials used at the time were lead and mercury due to their relatively low melting points. The 1970s saw ceramics use in flame spraying, which significantly expanded the range of applications and provided a much safer alternative than heavy metals. Fast forward to today, and traditional thermoplastic powder coatings can be effectively used in the flame spray process.

To learn more about the flame spraying process and how it has evolved over the past several years, I visited CEO Robert G. Langhans at his facility in Largo, FL, which houses IBIX Surface Technologies for portable blasting and U-Coat Technologies Inc. for protective coatings and engineered thermal flame spray equipment. These two synergistic companies supply impressive technologies that can be leveraged by many industries. IBIX offers micro air abrasion technology through a range of portable vapor wet blasting and deep cleaning equipment, from heavy duty blasting to impressive non-destructive capabilities. In fact, one of Robert’s favorite non-destructive demonstrations includes blasting the ink off the surface of a business card without impairing the paper in any way. This is why, Robert says, IBIX equipment has been used around the world in such places as Machu Picchu, the Eiffel Tower, and the Colosseum for historical preservation efforts. Robert offers a variety of eco-friendly abrasives, including superoxalloy from 10X Engineered Materials for heavy duty industrial blasting applications, which reduces dust and improves profile efficiencies during the blasting process.

U-Coat Technologies Inc, on the other hand, offers a variety of custom powder coatings, spray equipment, and accessories for mobile on-site field-applied flame spraying. Robert recalls they started supplying the oil and gas industry with flame spray equipment in 2011, offering two- and three-layer coating systems for corrosion protection. Between 2013 and 2014, Robert visited salt mines throughout South America, introducing the process to shield vital mining components from corrosion, erosion, and wear. Around 2015, U-Coat started gaining traction in the marine market, where customers were seeking tough protective coatings for buoys and barge hulls. This attracted the attention of Pacific Netting Products outside of Seattle, where they started using U-Coat from getting into power plants, as well as improve the longevity of their equipment and buoys.

Then, Robert reveals, around 2017 they learned how to successfully apply flame spray coatings on new and repaired concrete surfaces, opening a whole new market. By spraying polymer coatings on the surface of concrete floors, applicators provide their customers with a completely repairable surface that offers anti-slip features.


Today you can find flame spray used in the unlikeliest of places, including backyard pools, fishery tanks, and even waterslides at theme parks like Legoland. Robert says Alaskan fishing boats have even experimented with using luminescent flame spray on fishing hooks, so they glow in the dark and attract fish.

The Benefits
The first benefit of flame spraying comes from the powder coatings themselves. Powder coatings contain negligible VOCs and are an environmentally friendly technology, especially when compared to other corrosion prevention materials and processes. While electrostatic powder coating transfer efficiency can be as high as 70-80%, Robert explains that the flame spray process results in nearly no powder waste, achieving about 98% efficiency. This is because the powder is liquefied as it passes through the high-velocity, air-fuel, low-oxygen (HALO) flame cone and hits the heated surface in a molten state.

Field repair is also an obvious benefit of flame spraying. Some parts are too large or integrated into infrastructure and can’t be hauled away for restoration or repairs. Examples of this include architectural components, bridges, handrails, and parking lot bollard posts. A few U-Coat contractors focus almost entirely on municipal fire hydrants and bike racks. Depending on the application, there are different sized flame spray units with a variety of spray gun options and nozzles that can handle surface areas small and large alike.

While flame spraying can solve common challenges found out in the field, it can also solve a few found in custom coater shops. For example, some parts are so thick that the dwell time required to get them up to curing temperature is simply too costly and energy inefficient. Hot dip galvanizing and multilayer liquid paint systems have traditionally been used for these parts, but flame spraying can be a more environmentally friendly and flexible alternative to consider. Parts that are too long to fit into the oven can also be considered for flame spraying, depending on the coating requirements. Robert says that U-Coat equipment has been approved for coating highway tube signs in FL DOT projects. His customers have found that coating the poles in the field also allows the ability to coat over common coating failure points, such as welds, joints, and bolting points. By flame spraying over top of these typical nuisance areas after assembly, a layer of corrosion protection is added that normally wouldn’t be there.

Let’s be clear, however. Flame spray equipment doesn’t apply a Class A finish. These are purely functional coatings that may be applied as thick as 20 mils. As Robert puts it, “We get called when something has failed or to prevent something from failing; not to make it pretty.” While the finished surface as an orange peel effect, he says there are techniques to help minimize it. However, you still have the full range of colors available as well as custom blends of thermoplastic powder approved for flame spraying.

How Does It Work?
Now that we have an idea of where flame spray can be used, let’s look more in depth at how the process works. First, the surface must be prepared. Abrasive blasting can be used to remove previous coatings and other particulates to create a profile of around 2.0-2.5 mils using a medium grit between 60-80 mesh. The flame spray units themselves are fairly small, many not much larger than a portable powder coating unit.

As in a traditional powder coating system, compressed air moves powder through the unit. Robert says air consumption is about 20 cubic feet per minute (cfm) for the smaller guns, and as much as 45 cfm for larger ones. Hose lengths can go as far as 60-90 feet, depending on job site needs. Each unit contains a sieve to prevent clumping as the powder moves through, and dryer units are available to remove moisture from the system in areas where humidity is a concern.

While traditional powder coatings are applied electrostatically or in a fluidized bed, flame spray is sort of an augmented version of hot flocking, the process of heating up a part past the powder coating’s curing temperature, then applying the powder so it immediately begins to melt and flow as it collides with the surface. Hot flocking is sometimes used to apply powder coatings to non-conductive surfaces like glass, parts with complex geometry, or to correct minor surface imperfections. The main difference in flame spraying is that there are no electrostatics involved; instead, the powder is introduced inside a flame cone as it exits the nozzle (Figure 1), and the powder is activated as it passes through the flame cone and melts with velocity to impact the surface. This force also helps improve adhesion and overall coating thickness; even heat distribution supports a smoother finish.

The flame is produced by liquefied petroleum gas fed at around 43.5 pounds per square inch of pressure to feed the guns. Robert says he recommends at least a 100-pound tank for eight-hour uninterrupted workflow and to prevent freezing up during operation.

Standard thermoplastic powder coatings are not ideal for flame spraying, partially due to particle size. If the size of the powder particle is too small, it will not survive the heating process and essentially disintegrate before hitting the surface. Approved thermoplastic powder coatings are ideally suited for flame spraying and promote postforming capabilities, high durability, chemical resistance, impact strength, and of course, corrosion resistance.

Surprisingly, the flame spray process isn’t as hot and destructive to the application surface as one might think. To demonstrate this, Robert uses cut pieces of cardboard as paint swatches and applies flame spray coatings to them to show the flexibility of the coating and various colors available to customers.

Certified Contractors
As use cases for flame spray coatings grew exponentially over the years, U-Coat’s network of certified applicators also grew. They currently have certified independent contractors strategically placed around the continental U.S. and Alaska. Robert says he is committed to making sure their customers are adequately trained for success, because if they aren’t using the equipment properly, the technology won’t be as successful. They frequently fly contractors to their facilities for two-day hands-on training, which includes training on steel coating as well as concrete and fiberglass.

Robert also has a conference booth area set up in the warehouse where they shoot instructional videos for YouTube and can also hold impromptu Teams meetings to provide virtual, individualized trainings.

One of the benefits of staying in touch with their certified contractors, Robert says, is to help the company iterate new accessories that help solve challenges experienced out in the field. Based on feedback received from customers, U-Coat’s engineers have developed new, innovative nozzles for their blasting equipment, and a “backpack” flame spray unit designed for working in tight spaces. They are even developing a Skeletor system, or wearable exoskeleton, that will help relieve pressure on the shoulders, back, and thighs, while stabilizing movement for flame spray operators.

It is always refreshing when you see companies maintain close relationships with their customers, working to continually receive critical feedback that helps to iterate and improve products. That’s what continually pushes technology forward to solve everyday challenges, promoting quality and efficiency.

Troy Newport is publisher of Powder Coated Tough.