Hobart QCL-6 description: A premium copperless, mild steel solid wire, formulated to provide high quality welds and trouble-free performance in heavy duty, high-speed, spray-transfer applications to light duty, low-speed, short-arc applications. Because QCL-6 has a higher deoxidizer content, it can be used to weld light to moderately scaled or lightly rusted plate without pre-cleaning and still produce high quality welds.