The welding process has three basic areas, which are the positions, the processes, and the equipment. The positions are what people are doing at certain various specific times. The process is how each position is done as well as the steps involved. Lastly, the equipment used depends on what kind of welding a person wants to do. Welding is an electrical way to achieve bonding two pieces of metal together. It is commonly used in a variety of industries including construction, manufacturing and architecture.
1. Choose your method
There isn’t one welding process suitable for all applications, so you need to consider these factors: the type and thickness of the metal you’re welding, how big the job is, whether you’re welding indoors or outdoors, what you want the welds to look like, and your budget.
The most widely used form of welding today is electric arc welding, in which an electric arc melts an electrode (welding wire, for instance) and partially melts the base metal. When the molten metals cool, the parts fuse together. There are different types of arc welding, but we’re going to concentrate on MIG (metal inert gas). A form of wire-feed welding, it’s the easiest type to master, especially if you’re teaching yourself.
Metal Inert Gas (MIG)
Uses a weld gun that continuously feeds wire from a spool when the operator presses the trigger. Along with the wire, the weld gun simultaneously supplies a shielding gas that protects the metal from impurities in the air. MIG yields cleaner, better looking welds than stick welding.
Flux-cored arc welding (FCAW)
Similar to MIG, except there’s no separate shielding gas because the wire electrode has flux in its core, which creates its own shield as the wire melts. This windproof setup makes FCAW a good method for welding outdoors.
2. Buy your equipment
The welder is your biggest expense, so don’t cheat yourself—a cheap welder will only frustrate you and make learning more difficult. A wire-feed welder uses ordinary household current to produce an extremely hot, high-energy electric arc. Inside the machine is a small motor-driven spool of welding wire (the electrode). The wire is fed down a hose to a trigger-activated welding gun. When the operator touches the wire against the base metal, the arc melts the wire and partially melts the base. In MIG welding, as long as the trigger is down, the gun keeps feeding wire and gas.
The Lincoln Electric Power MIG 210 (above) is new technology for a great price: At 120-v or 230-v, it allows an ambitious beginner to MIG-, TIG-, and stick-weld. It costs $999.
At $767 the Millermatic 141 (below) is a nice introductory option. It’s a 120-v wire-feed welder that can be used to weld thin aluminum and steel between 24-gauge and 3/16-inch.
Tip: Your welder also has a work lead coming out of it. This is an electrical cable with a clamp on the end that attaches to the base metal and completes the electrical circuit required to weld. If dirt, rust, or paint interferes with the lead’s contact, your weld quality will suffer.
Wire is relatively inexpensive. A simple rule of thumb is to use a thin welding wire on thin sheet material, and increase the wire diameter as the material’s thickness increases. A welder takes at least two different diameters of wire.
The owner’s manual for the machine tells you what it takes, and there usually are instructions on the flip-up panel on the side of the machine. It’s all surprisingly intuitive.
Buying the right shielding gas is important, so make sure you know what type of job you plan on tackling. You can pick up a reusable tank of gas from your local welding supplier. The psi will vary depending on the type of torch you’re using and how deep you want your welds, but generally you’ll stick to between 15 and 25. As for the gas mixture, a home hobbyist with a wire-feed welder can usually get by with 100 percent CO2 shielding gas. For
a cleaner weld, use 75 percent CO2 and 25 percent argon.
Welding cart: Wire-feed welders can weigh up to 75 pounds, so build or invest in a welding cart to increase portability.
Awl or carbide scribe: to mark cut lines.
Right-angle grinder: for grinding, beveling, and flattening welds, as well as for surface preparation.
Miter clamp or magnet square: to secure joints.
Chipping hammer and wire brush: for cleaning up slag and spatter.
Welding pliers: to trim welding wire and remove spatter from the welding-gun nozzle.
Why you want an auto-darkening helmet: The light generated by any arc-welding process is incredibly bright, and it will burn your eyes if you’re not wearing a helmet. For years traditional welding helmets had a permanently darkened viewing shade, but that meant you had to flip your mask up whenever you weren’t welding. New auto-darkening helmets protect against harmful light emissions by automatically darkening their clear lens to a preselected shade in milliseconds, using LCD technology in their glass. Each helmet also has controls to personalize settings.
The Antra AH6-660-0000 Solar Power Auto Darkening Welding Helmet, seen above, provides lots of options, from $45 to $109, depending on lens size.
3. Prepping your weld
Ready the metals
Use a wire brush and acetone to remove oils and dirt. If you need to cut the metal, mark a line with your awl or carbide scribe, and cut along it with a metal-cutting chop saw, a hacksaw, or a grinder with a cutoff wheel.
Grind the edges
But only the ones you plan to join, and use a right-angle grinder. This is called chamfering. A chamfer is a bevel between the adjoining edges of two pieces of material, typically at 45 degrees. This creates a space for the filler and provides greater structural integrity to your weld. Doing this for butt joints, especially, is a good idea.
Position the metals
With your miter clamp or magnet square, secure the joints to keep the pieces of metal in the same plane before you begin the weld.
Tip: You are dealing with sparks, fire, and molten metal, so don’t start welding before putting on a welding jacket or apron, leather gloves, and a helmet. If you want to save money, a good-quality long-sleeve cotton work shirt can stand in for a welding jacket. Don’t forget your work boots (no sneakers), and remove jewelry from your wrists and neck. When grinding, put on safety glasses and a full-face shield. Keep an ABC fire extinguisher nearby too.
4. Layering your weld
Body and hand position
Think of the welding motion like a golf swing—you want as few moving parts as possible, and you want the motion to be fluid and repeatable. When possible, hold the welding gun with two hands, or use the wrist of your off hand to guide the hand holding the welder (think of a billiards shot). With the welder off, do a dry run to make sure your positioning is good. The steadier your hands, the better the weld.
Before starting, check your gun. The wire electrode should stick out between 1/4 and 3/8 inch. Make sure the nozzle is clear of spatter and that the wire tip is clean. Then make a few tack welds, just enough to connect the base metals, along the joint.
The final bead
After you’ve tacked the metals into place, you can lay down your final weld beads. Keeping the weld gun at about a 75-degree angle to the base, move slowly from left to right (if you’re right-handed), spending one to two seconds laying down each bead and maintaining a constant arc length. Don’t concentrate on the bright arc. Look at the edge of the weld puddle, and when you reach the end of your weld, pull the electrode back from the metal and allow it to cool.
5. Grinding your weld
If you don’t care how your weld looks, or if it’s on a piece of metal that won’t be visible when your project is completed, you can skip this step, because you are done. Congratulations—you’ve made your first welds. Work on perfecting your technique on scrap metal. Welding is a lot like playing the guitar: It’s not hard to do it a little bit, but to become proficient you need practice, practice, practice.
For a smooth finish, use a 36-grit grinding wheel attached to your right-angle grinder to grind along the weld path, not across it, for uniformity. Go slowly. If you grind through your weld, you’ll have to start over. When grinding, you should see only orange sparks. Blue means you’re pushing too hard. Once you’ve finished, grab a zirconia flap disc for precision shaping and finishing.