From cleaning and preparing to finishing, the new TIG Brush sets industry standards for stainless steel
Stainless steel is wonderfully versatile. It has a high resistance to corrosion and it’s aesthetically appealing. It’s not surprising, therefore, to find it in a wide variety of industries and end products – from building and construction to shipping vessels and medical equipment.
Most grades of stainless steel can be welded and fabricated readily, but there’s a catch. The process of welding stainless steel mars the metal with an ugly brown heat tint, commonly referred to as the heat-affected zone. Not only is it unsightly, but it also weakens the area of the stainless steel, leaving it open to oxidation. Although stainless steel is naturally passive, the welding process damages this thin chromium oxide film. Once this occurs, the stainless steel is said to have lost its passivity, and corrosion can become active in the defect site – the welded area.
Independent testing by Gauge Industrial and Environmental, using a Scanning Electron Microscope (SEM) and The Welding Institute (TWI) immersion test to ongoing standardization ISO CD18069, have shown the cleaning with a TIG Brush and genuine TIG Brush fluids removes detectable oxides from the weld zone and returns chromium levels in the surface layer to equal or superior levels than that of unwelded surface.
Making a difference
Traditionally, cleaning and re-passivation was only achievable through the use of highly toxic pickling pastes and gels or immersion acid pickling. Pickling paste or pickling gel is most commonly a combination of hydrofluoric and nitric acid and, depending on the concentration, exposure can cause severe burns and even death. Similarly, an acid pickling bath is generally a combination of hydrochloric and nitric acid, another concoction of dangerous chemicals.
Standard alternatives to pickling pastes and gel, however, come with their own set of shortcomings. Todd Cull, the general manager at Diamond Mfg., a manufacturer of perforated metal, plastic and other materials based in Kansas City, Mo., described electro polishing of the company’s stainless steel as being a time- and cost-consuming endeavour.
“We got a real education in electro polishing and passivation on stainless steel,” Cull says. “First it’s costly. Second, it sets us back two to four weeks in production. And third, even the electro polishing can give mixed results on the final product, such as hazing and white marks if all the acid is not neutralized in the overlaps on the sheet metal.”
As for the company’s experience with pickling gel, Cull says that some parts require 45 minutes for the solution to cure. And on top of that, the clean up process is substantial – “Not to mention no one wants to do that work,” Cull admits.
Luckily, the frustrations surrounding the cleaning of stainless steel at Diamond Mfg. didn’t last long. As Cull was flipping through an industry trade publication, he stumbled on an article about a TIG brush machine that he thought could be a real solution for the company’s applications. Cull and others at Diamond Mfg. discussed the possibility of investing in the TIG brush machine and eventually had a company representative come into their facility for a demo.
“We were sold as soon as we saw the machine clean up our worst welds in seconds,” Cull recalls. “[The rep] even showed us how the machine could etch and mark on stainless steel, giving us the opportunity for added-value possibilities in our products. The only question was which machine to get and how fast could we get one.”
Developments from down under
The equipment that Cull had stumbled on was developed by Ensitech; a company founded in Sydney, Australia, in 2006. The product, a fast, economical and safe alternative to traditional cleaning methods, cleans welding residue by combining an electro-chemical process with a special brush and environmentally friendly cleaning fluids. Not only is it fast and economical, it eliminates the use of hazardous chemicals.
The development is the brainchild of Ensitech’s managing director, Clive White. He invented the system in his garage in Australia after a friend who had won a manufacturing contract from McDonalds Corp. asked him to come up with a way to clean welds. The market had a need, and so he developed the technology. The TIG Brush became the form.
In 2013, Ensitech opened an office in Chicago and introduced the TIG Brush innovation to stainless steel fabricators in the United States during Fabtech, one of the metal fabricating industry’s biggest events. Unsurprisingly, White is encouraged by the positive response the TIG Brush has received in the United States and North America. He believes its success is due to its quality, safety and simplicity. “It provides one-step cleaning and passivation, requires little user training, and gives welders complete control over the surface finishing of their work,” he says. Ensitech continue to grow acquiring an increasing number of distributors and TIG Brush users throughout the United States and North America.
Like Cull and the team at Diamond Mfg., Dan James, an engineering specialist at Key Technologies, was looking for a better and faster way to finish its stainless steel products. Key Technologies manufactures conveyor systems and automated food systems in Walla Walla, Wash.
“The TIG Brush is about three times faster than the machine we were using,” says James. “Another feature we like is that it does not scratch the surface and gets into corners easily.”
James also heralded the savings that his company experienced with the cleaning itself. The company’s previous machine had a pump applicator and used a lot of cleaner. He relays that dipping a brush is a better solution because it reduces waste. And like Cull, James was happy to see the system’s etching capabilities.
“We do a lot of etching, so I tested the machine by adapting a head and used the etching chemical we had,” he explains. “The TIG Brush took two minutes to etch and the machine we use takes 15 minutes.”
As well as providing solutions to stainless steel weld cleaning and etching, the TIG Brush is also being used throughout the stainless steel industry in new and innovative ways. It’s capacity to prepare and finish stainless steel has been utilized in varying applications.
Clean as a whistle
Spooner Industries is a good example of the TIG Brush’s overwhelming success in unexpected applications. Spooner is a global supplier of technologies for the baking, drying, curing, proving/proofing, cooling and air pollution abatement industries and is always looking for methods to save time and money.
The company was dealing with a buildup of yeast contamination in the ducting and on the stairs into the ducting of their bakery, meaning that these surfaces were continually rusting. To adhere to industry regulations and remain in operation, both of these stainless steel surfaces needed to be cleaned on a monthly basis, which was an expensive and time consuming exercise for Spooner.
A visit by a U.K. TIG Brush distributor, however, radically changed their procedure. Using one of Ensitech’s solutions, TBE-700, the rust was removed and the surface was re-passivated. Not only did this simplify the cleaning process, but it also extended the length of time necessary between cleaning. On average, Spooner now only has to clean the areas every five to six months.
Another unexpected end application was realized by Adrian Davis, a renowned artist from Queensland, Australia. Davis was commissioned to create a stainless steel sculpture for the entrance to Queensland Gas building in Brisbane. The sculpture he created was a large stainless steel wave, consisting of 370 single pieces of stainless steel.
One of the requirements of this commission, however, was that this artwork was to be delivered and installed passive. So, rather than sending all of the pieces to Melbourne – a distance of 1,250 miles away – to be immersed in an acid bath for passivation, Adrian contacted Ensitech and purchased a TIG Brush. Using TB-31, a pH neutral weld cleaning fluid, he was able to passivate each section of the wave himself onsite, eliminating the need to package, transport and treat the pieces offsite.