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For professional fabricators and structural engineers across New Zealand, the choice of welding wire is never trivial. The wrong consumable can delay an entire project, cause costly rework, or create unsafe working conditions. When Nelson-based Trinder Engineers found themselves fighting a persistent CO2 gas supply problem, they needed a smarter solution fast. Their answer was the Hyundai SC-420MC dual-shield flux-cored MIG wire, and the results exceeded every expectation.

This case study explores why Trinder Engineers made the switch, how the SC-420MC flux-cored wire performed on a demanding real-world infrastructure project, and what fabricators across New Zealand should know before choosing their next MIG wire.

The Challenge: CO2 Supply Issues with Hyundai Supercored 71H

Trinder Engineers had long relied on the Hyundai Supercored 71H, a well-regarded E71T1 titania flux-cored CO2-shielded MIG wire widely used in structural steel and general fabrication. The 71H delivers consistent arc performance and solid all-position capability, making it a trusted choice for workshops running high-volume weld schedules.

However, the 71H wire has one firm dependency: CO2 shielding gas. As supply chains tightened across New Zealand, obtaining a reliable flow of CO2 cylinders became increasingly difficult for the Trinder Engineers team. Delays in gas supply led to delays on the workshop floor, resulting in missed project milestones and unnecessary operational pressure.

As Prosser, an experienced fabricator at Trinder Engineers, explained: "We just switched to that SC wire from the old 71H because it was hard to get the CO2 gas."

Rather than work around the problem indefinitely, the team decided to evaluate a flux-cored wire with greater shielding gas flexibility.

What Is the Hyundai SC-420MC? Understanding Dual-Shield Rutile Flux Cored Wire

The Hyundai SC-420MC is a dual-shield, all-position rutile flux cored wire classified to AWS E71T-1. It is available in 1.2mm and 1.6mm diameters on 15kg spools and is suited to a wide range of structural and fabrication applications.

The term "dual-shield" is important. Unlike a single-shield flux cored wire that relies solely on gas generated from the flux core, dual-shield flux cored wire uses both the flux core and an external shielding gas. The SC-420MC can operate with CO2 alone or with a mixed argon/CO2 shielding gas, giving operators genuine flexibility depending on what shielding gas is available on site or in the workshop.

This flexibility is precisely what resolved Trinder Engineers' supply chain problem. When CO2 was scarce, the team could switch to a mixed gas without changing their wire or adjusting their WPS significantly. The SC-420MC flux-cored wire worked reliably with both shielding gas options, keeping the workflow running without interruption.

Key technical characteristics of the SC-420MC include:

• Classification: AWS A5.20 E71T-1 (all-position)
• Shielding gas: CO2 or Ar/CO2 mix
• Diameters: 1.2mm and 1.6mm
• Spool weight: 15kg
• Applications: Structural steel, bridges, shipbuilding, vehicle fabrication, chemical plant machinery, general metal fabrication

For fabricators seeking a high-performance MIG wire that does not lock them into a single gas type, the SC-420MC presents a compelling case.

The Maitai Golf Course Bridge: SC-420MC in Action

The most significant project Trinder Engineers undertook with the SC-420MC flux-cored wire was the construction of a replacement bridge for the Maitai Golf Course. The previous bridge had been destroyed by severe flooding, and the new structure needed to meet stringent engineering and compliance standards.

The brief called for a 36-metre-long bridge built in three separate sections. Every joint, every weld, and every pass was catalogued, numbered, and recorded as part of a thorough quality management process. There was no room for inconsistency. The SC-420MC was selected from the outset because of its ability to produce high-quality, repeatable welds with minimal cleanup between passes.

Structural steel bridge fabrication places specific demands on a MIG wire. Out-of-position welding, particularly vertical-up runs on web and flange connections, requires a wire that maintains arc stability and controls the weld pool without excessive heat input. The SC-420MC delivered precisely this. Its low-spatter arc, excellent slag release, and controlled bead profile made vertical weld passes straightforward, even for less experienced operators on the team.

Prosser noted that the SC-420MC proved "much more forgiving than the old wire," particularly in vertical weld applications, which are notoriously demanding even for seasoned fabricators.

Performance Benefits: Why the SC-420MC Outperforms Traditional Flux Cored Wire

Based on experience with Trinder Engineers, the SC-420MC offers clear performance advantages over many conventional flux-cored MIG wires.

Reduced Spatter and Fume Generation

One of the most immediate improvements the Trinder Engineers team noticed was the reduction in spatter. Less spatter means less time spent grinding and cleaning between passes, directly reducing labour costs on high-volume fabrication projects. It also means a cleaner working environment, which is important for workshops where health and safety are taken seriously.

Welding fume generation was also noticeably lower with the SC-420MC compared to the Hyundai Supercored 71H. For shops that weld in enclosed or partially enclosed spaces, lower fume output reduces the burden on extraction systems and helps meet workplace exposure standards.

Excellent Vertical Weldability at Low Current

The SC-420MC is specifically designed to excel in out-of-position welding, including vertical-up applications. By delivering a stable arc at relatively low current settings, it gives the operator better control over heat input and weld pool behaviour. This makes it significantly easier to produce uniform, correctly profiled welds in the vertical position without resorting to a weave technique, saving time on every pass.

Superior Arc Stability and Crack Resistance

The SC-420MC produces a smooth, stable arc that is consistent across a wide range of parameters. This consistency is critical in structural work, where operator variability can introduce quality risks. The wire also offers excellent crack resistance, an important property in applications subject to dynamic loading such as bridges, vehicle chassis, and crane components.

User-Friendly for All Skill Levels

Perhaps the most telling feedback from Trinder Engineers came regarding apprentice welders. In a workshop environment, newer operators are often given simpler tasks while they develop their technique. With the SC-420MC, apprentices were able to complete complex structural welds with confidence from the outset. As Prosser put it: "This stuff just seems much more user-friendly and easier to use."

For workshop managers, this is a significant operational benefit. A forgiving, easy-to-set-up flux-cored MIG wire reduces training overhead on each new job and limits rework that can otherwise arise when less experienced operators tackle challenging positions.

Cost Efficiency: Getting More from Your MIG Wire Budget

Switching welding consumables always prompts the question of cost. Prosser summed it up plainly: "Everyone's happy if the gas is cheaper and the wire works just as good."

The SC-420MC delivers on both counts. Its compatibility with argon/CO2 mixed gas means workshops can take advantage of mixed gas pricing, which in some markets is more stable and accessible than bulk CO2 alone. Combined with reduced spatter cleanup time, lower fume extraction load, and greater first-pass success rates, the total cost of use for the SC-420MC compares favourably with alternatives, even when the per-kilogram price of the wire itself is similar.

For fabricators running projects with tight margins and firm delivery schedules, these efficiency gains compound quickly across a full welding programme.

Browse the full range of MIG wires available at Proline Industrial to compare options for your application.

Who Should Consider the Hyundai SC-420MC?

The SC-420MC is not a niche product. Its all-position classification, dual-shield capability, and broad application range make it suitable for a wide variety of structural and fabrication workshops. It is particularly well-suited to:

Structural steel fabricators working on bridges, buildings, and infrastructure

Workshops with mixed or variable gas supply that need a wire that tolerates both CO2 and Ar/CO2

Shops training apprentices, where a forgiving, easy-to-dial wire reduces rework

Projects with rigorous quality management requirements, where weld consistency and traceability matter

Applications requiring out-of-position welding, including vertical-up and overhead passes

If your team is currently using the Hyundai Supercored 71H and experiencing any of the challenges described above, the SC-420MC is a direct, proven upgrade path worth evaluating.

Conclusion

Trinder Engineers' shift to the Hyundai SC-420MC demonstrates something that experienced fabricators know well: the right welding wire does more than produce a bead. It determines how smoothly a workshop runs, how consistently apprentices and experienced welders can hit quality targets, and how resilient an operation is when supply chains become unpredictable.

The SC-420MC flux-cored MIG wire resolved a genuine supply chain problem, improved weld quality and operator experience, and proved itself on a demanding structural infrastructure project. For New Zealand fabricators seeking a reliable, versatile, and user-friendly flux-cored wire, this product warrants serious consideration.

View the Hyundai SC-420MC Dual-Shield Flux Cored MIG Wire or explore the full MIG welding range at Proline Industrial.

Welding fume is a confirmed human carcinogen. The International Agency for Research on Cancer classified it as Group 1 in 2017, and WorkSafe New Zealand continues to update its guidance on controlling worker exposure to welding fumes in industrial environments. Despite this, many workshops across Aotearoa still treat fume management as an afterthought, relying on open doors and natural ventilation to do the heavy lifting.

Trinder Group is not one of them. Under the leadership of Managing Director Kerry Hill, this Nelson-based engineering firm has positioned itself at the forefront of workplace health and safety, investing seriously in at-source welding extraction to protect its workforce. Their story is worth sharing, because it illustrates exactly what responsible industrial practice looks like in the real world, and why the choice of industrial fume extractor matters far more than most businesses realise.

The Invisible Threat Inside Every Welding Workshop

Welding fumes are not simply smoke. They are a complex mixture of metallic oxides, silicates, and fluorides generated when base materials, coatings, and filler metals are heated above their melting points. Particles at the ultrafine end of the spectrum, those under 0.1 microns in diameter, penetrate deep into the alveolar region of the lungs and are not expelled through normal respiratory function.

Short-term effects include irritation of the nose, throat, and eyes. Long-term, repeated exposure is associated with chronic obstructive pulmonary disease, lung cancer, neurological damage from manganese, and in some cases, metal fume fever. The risk is not theoretical. It is the daily reality for welders who work in environments without adequate extraction and filtration.

For Trinder Group's welding supervisor Wayne Martin, this is personal. Years of working in environments with limited fume control left him with respiratory issues that continue to affect him today. That lived experience is precisely why he has become one of the most vocal advocates for upgrading welding extraction systems across the business. When someone with that background tells you the new equipment makes a visible difference, it carries real weight.

Trinder Group's Approach to Welding Extraction

Kerry Hill frames Trinder Group's approach to welding extraction in straightforward terms: "Welding fume isn't good for you, and so we're looking for every practical way to reduce the fume."

That principle has driven a series of equipment upgrades focused on at-source capture, the most effective method of controlling welding fumes because it intercepts contaminated air before it has any opportunity to disperse into the breathing zone of the welder or surrounding workers. Rather than relying on general ventilation to dilute fumes across a large workshop space, at-source systems draw contaminated air directly away from the arc point, filter it, and return clean air to the environment.

This approach aligns with WorkSafe NZ's hierarchy of controls, which prioritises elimination and engineering controls above administrative measures and personal protective equipment. At-source fume extraction sits at the engineering control tier, making it one of the most defensible and effective strategies available to workshop operators.

Trinder Group has integrated purpose-built welding fume extraction systems into their welding operations, selecting equipment that captures fumes directly at the torch rather than relying on ambient extraction alone. The results have been immediately observable.

What At-Source Industrial Fume Extraction Actually Does

Understanding the mechanics helps demystify the technology. A quality industrial fume extractor operates on the same fundamental principle as a high-powered vacuum, but engineered for the specific demands of welding environments rather than general industrial cleaning.

Inside the unit, a motor drives a turbine that generates significant negative static pressure. This pressure differential draws contaminated air through a suction point positioned close to the welding arc. That air travels through internal filtration stages, typically including a pre-filter to capture larger particles and a high-efficiency main filter designed to capture ultrafine metallic particulates. Cleaned air is then returned to the workshop.

At-source extraction torches take this a step further. A fume extraction MIG torch functions identically to a standard MIG torch in terms of welding performance, using the same consumables, wire, and cable. The difference is a built-in housing and a front-end shroud that captures fumes as they are generated, before they can rise toward the welder's face. A secondary hose running alongside the torch cable carries the captured fumes back to the extractor unit.

The critical calibration point is vacuum pressure. Too low, and fumes escape capture. Too high, and shielding gas is drawn away from the weld puddle, risking porosity. Finding the right balance is straightforward once operators understand the adjustment range, and modern extraction units make this easier with adjustable flow controls.

The filter tray tells the story plainly. Senior tradesman Damian at Trinder Group describes the revelation of opening the tray after a relatively short period of use: "It's surprising how much it picks up when you empty the tray." That accumulated particulate is material that, without extraction, would otherwise have been breathed in by the people working alongside him.

Beyond Compliance: The Moral Case for Better Industrial Air Quality

New Zealand's Health and Safety at Work Act 2015 sets a clear legal obligation to manage workplace hazards so far as is reasonably practicable. For most industrial environments, investing in modern welding extraction equipment is entirely within that definition of reasonable practicability, particularly given how significantly the technology has advanced and how competitively it is now priced.

Kerry Hill does not stop at the legal argument, however. "There's a moral obligation as well just to be doing the right thing," he says. That statement reflects a broader shift in how forward-thinking New Zealand businesses are approaching occupational health. Compliance sets a floor, not a ceiling. The question Hill poses, "Is the minimum good enough?", is one every workshop operator should be asking themselves.

Extraction and filtration equipment innovators in the industrial sector are increasingly designing systems that do not require operators to make trade-offs between welding performance and fume management. Modern at-source extraction integrates with standard MIG setups without disrupting arc stability or welder workflow, removing the traditional friction point that led many businesses to deprioritise fume control.

The business case reinforces the moral one. Respiratory illness results in ACC claims, lost productivity, reduced workforce capability, and reputational consequences that extend beyond a single site. The cost of prevention is a fraction of the cost of management.

Choosing the Right Industrial Fume Extractor for Your Workshop

Not every workshop has the same requirements. The right industrial fume extractor for a single-operator MIG bench differs from what a busy production floor with multiple welding stations needs. Key considerations include:

Number of welding positions. Multi-station environments benefit from systems capable of handling simultaneous extraction points, or separate units allocated per station to maintain consistent capture efficiency.

Process type. MIG welding with standard wire typically generates different fume compositions than flux-cored, stainless steel, or aluminium welding. Confirm that the filtration specification of any unit you consider is rated for the materials you work with.

Filter change intervals and running costs. A lower purchase price means little if filter consumables are expensive or require frequent replacement. Ask for guidance on filter life based on your expected hours of use.

Mobility requirements. Fixed-position welding suits bench-mounted extraction. Mobile operations or site work require units with appropriate portability, hose length, and stability for varied environments.

Compliance documentation. For businesses subject to audit, choose equipment with documented filtration ratings and retention filter specifications that can be referenced in health and safety records.

Proline Industrial's welding fume extraction range includes options suited to both single-operator setups and higher-demand multi-station environments, with units available for MIG torch extraction and freestanding ambient extraction to complement at-source systems. If you are unsure which configuration suits your workshop, the team can advise based on your specific processes and layout. 

Extraction and Filtration Equipment Innovators Raising the Standard for NZ Workshops 

Trinder Group's investment in welding fume extraction is not an isolated decision. It reflects a gathering shift across New Zealand industry, as more businesses move from reactive to proactive health and safety management, particularly in the welding sector where fume exposure risks are well established and the tools to address them are readily accessible. 

Kerry Hill and his team have demonstrated that prioritising at-source welding extraction does not require compromising on productivity, throughput, or weld quality. It requires choosing the right equipment, understanding how to set it up correctly, and committing to a standard of workplace health that goes beyond the minimum required by law. 

For workshops that have not yet reviewed their fume management approach, the filter tray test is a sobering starting point. Run your current setup, open the tray, and see what your workers have not been breathing in. Then consider what they have been. 

Proline Industrial supplies welding fume extraction systems throughout New Zealand, with warehouses in Nelson and Auckland for fast, reliable delivery. Explore the full range of welding fume extraction equipment online.