Connected To The Land 04-2018-Fall-718-PM96 - Page 32

WELDING STILL LEARNING EVERY DAY Story by Helen McMenamin. Top photo courtesy of Steven Le Boutillier, Lincoln Electric. B asic welding is a skill that most people can learn with a bit of practice, but you can keep getting better, learning to work different materials and with different machines as long as you work at it. Welding depends on the heat of an electric arc that’s created when an electrode is a small distance from grounded metal, and adding filler to the molten metal. Along with the heat, a welding arc produces infrared energy – stray heat and ultraviolet rays – the rays that cause sunburn, a burn that takes time to develop. The ultraviolet and infrared can damage your skin and eyes and the characteristic welding sparks are actually balls of molten metal, which can burn. SAFETY As head of customer relations for Lincoln Electric, a name synonymous with welding, Steve LeBoutellier listens to all sorts of welders all over the country. His strongest advice is the same no matter how long or what you’ve been welding: Stay safe. Buy protective gear along with your first welder, keep them in good shape and use them every time, he says. Take some time to choose a helmet – and be prepared to pay for it. The helmet protects your head and especially your eyes from harmful ultraviolet and infrared waves as well as flying hot metal, so it must meet a CSA or ANSI standard. An auto darkening helmet avoids the challenge of getting into position for a weld and then putting your helmet down before striking your arc. That can be a challenge, especially for occasional welders, and a bad start to a weld can mean a weak weld or a lot of grinding to clean off excess metal. Auto darkening makes tack welding easier and avoids the risk of a flash if the helmet isn’t locked in position. You also need safety glasses, and if you choose a passive helmet wear them with your helmet – if the helmet doesn’t lock, the glasses protect against spatter. You need leather gloves without holes, a dry long sleeved wool or fire-resistant cotton shirt with no open pockets and cotton or wool pants with no cuffs to catch sparks or spatter, 32 and leather boots. Synthetic fabrics and welding sparks are a poor combination. some welders can be used with flux-core wire without the gas tank outside. “Before you start welding clear away all flammable materials – sawdust, straw or containers of flammable material like gas or spray cans,” says LeBoutellier. “Spatter and sparks can smolder unnoticed. Get comfortable and trace your welding line to be sure you have full range of motion and can keep steady for the full length of the weld. TIG welding uses a gas bubble to protect the weld, but the gas is argon or helium rather than the CO2 used with MIG welding. A very fine tungsten rod is the electrode and it needs no filler metal so welds can be very precise, but it’s not easy. An experienced welder can make the cleanest welds with no splatter on thin metal, including aluminum and steel, with no waste and no filler. It’s particularly useful on car bodies, motorbike parts and sculptures, but it’s a challenging process and can be susceptible to fluctuations in power from the local electrical grid. I think of welding as like driving. It can be dangerous, but if you follow the rules and pay attention it’s perfectly safe.” WELDING SYSTEMS All welders use the same principles, but different engineering for various materials and types of work. Higher voltage (230 compared to 110 volts) machines produce more heat and melt metal deeper into the joint. Achieving a good weld means keeping the molten metal free of contamination and completely filling the joints. Each type of welder has advantages and drawbacks for various types of work and materials. Traditional stick welding uses flux-covered rods to prevent contamination and fill gaps and can overcome some rust and dirt. MIG and TIG technology use an inert gas around the molten metal, preventing nitrogen and oxygen in air from forming bubbles in the weld that make it porous and weak. The metal must be clean and not too thick. MIG welding (officially gas-metal arc welding, GMAW) is the easiest system to learn because the process is controlled from the gun. The metal electrode filler is automatically fed into the puddle when the trigger is on. MIG welding can be used to join different metals and makes a clean bead, making it good for sculpture. A good machine has a range of power outputs for various types and thickness of metals, used generally on metal under ¼ inch (6mm) thick. It’s important to have clean, dry, oil-free metal with no dirt or oil for MIG welding. And, it is for indoor use only, as wind disrupts the protective bubble of gas around the weld. But Stick and flux core welding make the strongest welds and can be used on very thick materials, including cast iron. The electrode is a metal rod (filler) coated in flux (protection). The flux forms a protective coating over the weld – slag that has to be chipped off afterwards. Flux core machines automatically feed a metal wire with a core of flux that forms slag or a protective gas bubble over the weld. Stick welding machines use AC or DC and some can switch between AC, DC+ or DC-. Direct current produces a smoother arc because all the electrons are moving in the same direction and DC+ and DC- give you deeper and shallower welds. Stick-welding machines are reliable and long- lasting and those that use AC only are lowest cost. Prices go up as the machines become more sophisticated with more options. The learning curve is steep, but the process can be used in wet or windy conditions, even off a generator, and is tolerant of oily and dirty material. But, the welds are not pretty and it’s easy to burn holes in thinner material. Welding opens a vast array of possibilities in making and repairing all sorts of metal things. But it does take practice and a willingness to learn. Hands-on courses are generally well worth the investment, but if those aren’t accessible there are many You Tube videos and online forums to help. You can become competent in a matter of months, but as one welder with 35 years’ experience, puts it, “I still learn something new almost every single day.” W Connected to the Land