WELDING 101A welder isnt usually the most sought after tool by many do-it-yourselfers. A welder can,however, be a very handy and important tool for the contractor or those who want torepair or build metal projects around the home. Welders are a necessity around thefarm and ranch, as well as for those doing auto repair work. Welding and welders mayseem daunting to the first timer and, indeed, welding can be challenging, requiringlearned skills. These days welding, however, isnt just for shop class nerds orprofessional metalworkers; it can be fun, and any number of modern-day tools makewelding easier for even the first timer. Many modern welders are also less expensiveand dont require a special 220-volt circuit. Larger models do, however, require a 220-volt circuit.Types AvailableFour basic welding tools and techniques are used: arc (stick), MIG, TIG andoxygen/acetylene. Each welding technique has its advantages and disadvantages.Stick welding has been the most popular method for most home-shop welding for along time. Stick welding uses an electric current flowing directly between a gap betweenthe metal and the “stick” or arc-welding electrode. The current causes part of theelectrode to melt, allowing it to mix with the metal of the work piece and form the weld.The electrode has a flux coating that burns to form a protective shield around the arc.Stick welding is the most effective method for welding many different alloys or joints.Stick welding can be used outdoors or indoors or in drafty areas, is the most economicalmethod and will weld on rusty or dirty metals.Stick welding does have some disadvantages. It is limited to metals no thinner than 18gauge, requires frequent rod changing, has lots of splatter and the welds must becleaned up after they are finished. Stick welding is also more difficult to learn and use,particularly in striking and holding the arc. Arc welders are available as either AC or DCor AC/DC. AC welders are the most economical and are used for welding thicker metalsof 1⁄16 inch or more. They are the best choice for farmers, hobbyists, and homemaintenance chores. DC welders provide cleaner welds, fewer arc outages, lesssplatter and sticking, and better control on thinner metals. They are also moreexpensive.
Above: The traditional type of welding for homeowners has been arc or stick, but ittakes practice to strike the arc and hold it properly.MIG welding (GMAW) (also sometimes called wire-feed) uses a wire welding electrodeon a spool that is fed automatically at a constant selected speed. The arc created by anelectrical current between the base metal and the welding wire melts the wire and joinsit with the base. This produces high-strength welds with a very good appearance andlittle need for cleaning. MIG welding also uses a gas shield process with gas fedthrough the welding torch and acting as a shield at the arc. This prevents oxidation andcontamination of the base metal. The gas utilized may be inert or active, depending onthe base metal to be welded. MIG welding is clean, easy and can be used on either thinor thicker plate metals.Above: Wire-feed welders feed a wire through a gun and are easy to use, produce cleanwelds and many are now sized perfectly for homeowners.A similar type of wire-feed welding is FCAW. It is slightly different from MIG welding inthat it does not require a shielding gas. This gas-free welding uses flux-cored weldingwire to shield the arc. This form of welding is the simplest, very efficient and extremelyeffective, especially when welding outdoors in windy conditions.Both MIG and FCAW are very easy to learn and can create super-clean welds onsteel, aluminum and stainless. MIG and FCAW weld materials as thin as 26 gauge.
Another form of welding is TIG, also called Heliarc. It utilizes tungsten inert-gas and isused primarily by professionals.Oxygen/acetylene welding utilizes oxygen and acetylene mixed at the torch to producea flame hot enough to melt metal. It can be used for metal cutting as well as weldingpurposes. Oxygen/acetylene welding takes quite a bit of practice and skill, as well asquite a bit of safety rules in storing and using the gases.SafetyWelding, like many work procedures, can be dangerous if you dont follow safety rules.1. Work in a safe area, free of all flammables, with both a fire extinguisher and a bucketof sand available.2. Exposure to a welding arc is extremely harmful to eyes and skin. Prolonged exposurecan cause blindness and burns. Never weld unless you are adequately protected. Weara heavy, long-sleeved shirt, cuffless pants, high-topped shoes, flameproof weldinggloves and a protective welding helmet.3. Read and understand the welders owners manual.Above: Auto-darkening helmets, like ArcOne, which we carry on our website, make iteasy to see the gun or stick placement but provide instant darkening.Basic PracticesThe following steps are the basics for MIG or arc welding. Its extremely important thatall metal surfaces to be joined are free of rust, dirt, scale, oil and paint. If the surfacesare not properly cleaned, the weld can be porous and brittle. Remove oxidation and dirtwith a steel-bristled wire brush. Remove all oil or grease with a good cleaner.
The metal to be welded, as well as the ground-clamp area, must first be cleaned of rust, scaleand grease.Aluminum requires even more preparation. First, use a good chemical aluminumcleaner. Aluminum has an anodized surface and this must be wire brushed, sanded orground off the surfaces to be welded, as well as anywhere the ground clamp is to beplaced.If joining thick metal pieces, they should first have their edges beveled with a metalgrinder. The angle of the bevel should be approximately 60 degrees at the point ofcontact.A variety of joints are used to fasten the metal pieces together. Below is a chart of themost common joints.:Connect the ground clamp to the work piece and as close as possible to the area to bewelded. On-board computer systems of automobiles can be damaged if the ground
clamp is connected directly. Do not weld until you have disconnected the cable from thebattery that is attached to the chassis ground.When first learning to weld, its a good idea to practice on scrap metal. Try different heatsettings, base metal thicknesses and welding positions for each type and size of wireyou will be using. Make sure you read and understand the owners manual. Then turnon the welder and follow the manufacturers instructions on tuning in the wire speed andheat settings.Properly holding the gun is important for wire-feed welding. The gun can be held in twobasic methods, depending on the type of weld being made. Because the welding tip isdesigned with the contact tip recessed from the end of the nozzle and the nozzleelectrically insulated from the rest of the gun, wire-feed welding is easy to learn. Youcan actually rest the nozzle on the work piece and drag it along. This is very helpful forbeginners. Stick welding requires that you first touch the work to strike an arc, then liftthe electrode to prevent it from sticking and this takes some practice and skill.Wire-feed welding is really quite simple. Line the gun up in the proper position on thejoint to be welded. Lower your helmet or hold up a welding shield and pull the trigger tostart the arc. In a second or two youll notice a weld puddle beginning to form and thebase of the bead beginning to build. You can either push or pull the gun to move it alongthe weld joint. When welding aluminum, its best to push the gun as this creates acleaner appearance. Move the gun steadily and at the right speed to create a solid weldwithout lumps or an uneven bead. This part does take some practice, but its still easierthan stick welding.The wire spool is first loaded into the welder and the wire fed through the gun.
The wire-feed rate and amp settings are then set to suit the material being welded.Stick welding begins by first selecting the proper electrode. The electrode is basically arod coated with flux. The type and thickness of the metal and the position of the workpiece determines the electrode type and amount of heat needed.Naturally, the thicker metals require more heat. Welding electrode and arc-weldermanufacturers provide selection charts as to the electrodes needed for specific chores.You must next select the proper amperage for the electrode and the work piece. Turnon the welder, set the amps, protect your eyes and strike the arc. It is akin to striking amatch, scratching the tip of the rod against the work surface, and then quickly lifting it tothe required 1⁄8-inch. This gap must then be maintained consistently during the weldingprocess. If the gap becomes too narrow the electrode will stick to the work surface. Ifthe gap becomes too wide the arc stops. At the same time you are maintaining theproper distance, you must also maintain a consistent rate of travel with the rod along thejoint to create a proper bead. Too fast and the joint will be weak. Too slow and the beadwill overbuild with more slag. This does take practice, and its best to practice on scrappieces.
Above: Arc or stick welding requires a bit more skill. The arc is made by scratching thestick across the metal surface, then immediately lifting it and holding it 1/8" above thesurface.Two types of beads are commonly used: stringer and weave. A stringer bead is createdby moving the gun in a fairly straight line and keeping the nozzle and wire centered onthe joint. This, naturally, is the easiest bead to make. A weave bed is used when youmust deposit metal over a wider space than with a stringer bead. This is made bywaving the gun nozzle side to side while moving along the weld.Quite often, more than one bead is required to fill the V shape ground into the joint, aswell as to create a strong joint. If using a stick welder, or a self-shielding, flux-core wirein a wire-feed welder, you must chip and brush the slag off each bead after it cools andbefore making another pass. This slag must also be removed when the weld is finished.Welders AvailableBoth stick and wire-feed welders are available in a wide range of sizes, rated by theamperes they create. Its important to note the duty-cycle when purchasing a welder.This is the percentage of actual weld time that can occur in a ten minute interval. Forexample with a 20% duty cycle, actual welding can only occur for two minutes, and thenthe machine must cool for eight minutes. Stick welders range from 50/70 amps up to50/230 amps output. The smaller welders are 115 volt, the larger welders require a 220-volt circuit. The smaller welders will handle materials up to 1⁄8-inch thick, while thelarger welders can weld steel up to 3⁄8 inch in one pass.
Wire-feed welders range from 30/70 up to 30/85 in 115-volt, 220-volt models up to 200amps. Wire-feed models are available as flux-core or MIG. The former are the easiest tooperate as they require no gas. You can learn to weld in minutes. Many MIG units arealso available to weld with flux wire or with gas. This allows you to learn to weld theeasy way with the flux wire. Then simply add the gas bottle for more advanced welding.A wide range of welders, including arc, MIG, TIG and oxygen/acetylene are available atwww.nhproequip.com.Many welders come with a hand-held welding shield. If you do much welding you willappreciate a welding helmet. Auto darkening models such as the ArcOne weldinghelmets, make it easy to see the beginning placement of the gun or stick, yet instantlydarken to protect your eyes.Dont be afraid to tackle welding. Todays tools make the chore easy for even a first-timer, and youll probably find its fun and addictive. -courtesty of www.extremehowto.com/