In the world of welding there are three techniques which receive the majority of the attention. These are SMAW (shielded metal arc welding), GMAW (gas metal arc welding), and TIG (tungsten inert gas) welding. There are important differences in the process and capabilities of each, so it is important to understand their unique characteristics.
SMAW welding, which stands for Shielded Metal Arc Welding, is one of the world’s most popular welding processes. Also known as stick welding, flux shielded arc welding and manual metal arc welding (MMAW), this is a relatively uncomplicated process as it uses simple equipment and it’s fairly straightforward to learn. Having said that, there are a whole wealth of techniques to learn and tips to help you perfect your results, all of which we’ll cover in this ultimate guide.
What is SMAW welding?
SMAW welding is a process which uses a consumable electrode which is covered with a flux. The welding machine is hooked up to a power source, which creates either alternating current (AC) or direct current (DC) to form an arc between the electrode and the metal.
As this arc forms, both the electrode and the metal melt, forming a molten puddle known as the weld pool. At the same time, the heat from the arc burns off the flux, which forms a layer of gas to protect the weld from certain atmospheric gasses which can affect the weld’s quality. This negates the need for a separate tank of shielding gas – and without it you’d end up with weak, brittle welds.
As the weld pool cools, it solidifies to form a joint. This process also forms a layer of slag which has to be chipped off – which does make it less time efficient than many other types of welding – but choosing the right electrode can help to speed up the process.
Typically, SMAW welding is used for heavy-duty, industrial steel and iron jobs, but it can be used to weld aluminum, and other metals as well.
SMAW
SMAW stands for shielded metal arc welding. This is also commonly called ‘stick’ welding. In SMAW, the electrode is a metal rod or stick held in the torch with a small clamp. The rod has a solid coating of inert materials which vaporizes as you weld. This creates an inert cloud or gases which protect the molten metal and displace any oxygen that might come into contact with it. The gas cloud settles on the pool of molten metal as it cools, and is referred to as ‘slag’. The disadvantage to SMAW is that the slag must be chipped off of the weld after it cools, and can sometimes infiltrate the weld causing weakness.
SMAW Welding Techniques
Before you actually start stick welding, it’s essential to get your hands on a welding helmet and other protective clothing, including jackets, aprons, and even boots. Aside from the blinding light from the arc and the heat which are both produced with this process, you need to be adequately protected from all the slag and spatter which forms.
Make sure that your metal is clean as any dirt and imperfections can affect the strength and quality of the weld. Next, fit your chosen electrode into the welder and select the appropriate amperage (read the manufacturer’s guidelines if you’re unsure about this) and you’re ready to weld.
To start the arc (and consequently the SMAW welding process), simply scratch the electrode sharply against the surface of the metal, then draw it away slightly. This should be done in one smooth movement. The arc will form between the metal and the electrode, and both will begin to melt.
SMAW Welding Techniques
Welding Positions
In all welding positions, consider the effect that gravity will have on the weld pool before you begin. This is effectively a pool of molten metal so it will behave in a similar way to other metals, so make sure you position yourself correctly to weld as safely and effectively as possible.
Horizontal and vertical welds can both benefit from having backing plates and beveled edges, and in both cases, you should hold the electrode at 90° to the metal that you’re working on.
Overhead welds can be slightly more tricky in that you have to be careful of spatter and burns. Once again, backing plates can help. For flat welds you should hold the electrode at 90° to the base metal, but in any case you should always try to tilt it slightly to prevent any drips from falling onto your equipment.
Groove Welds
Use a plasma cutter or a grinder to create beveled edges on thicker materials measuring more than 3/16″, while you can stick with a square groove weld for thinner metals.
Basic Groove Welds
Whether you’re doing square groove welds or V-groove welds, keep the electrode at right angles to the metal, but lean it in the direction that you’re welding. If you tilt it in any other direction your welds will be ineffective and the whole process will be awkward and dangerous.
T-Joint Welds
For fillet joints, keep the electrode at a 45° angle to the weld. For lap joints, on the other hand, you should keep the degree much tighter, moving the electrode in a circular motion to enhance its strength. In both cases, you should aim to weld both sides of the joint in order to make it stronger and more durable.
Fillet Welded T-Joint
Troubleshooting Tips
While you’re still getting to grips with SMAW welding techniques, there is a number of problems which you might encounter. Part of the enjoyment of welding comes from trying out different things and practicing the art of welding until you’ve perfected it, but here’s a quick run through of some SMAW welding tips and tricks to get you out of various sticky situations.
When you’re trying to start your arc, your electrode might get stuck to the metal. Don’t panic: simply twist the electrode slightly and it will work loose, allowing you to try again.
GMAW
GMAW stands for gas metal arc welding. This is also commonly referred to as metal inert gas welding, or MIG welding. In GMAW the electrode is a roll of wire which the welder feeds out of a ‘gun’ to the work piece. You control the speed of the wire, so you can make long welds without stopping to replace a rod. This type of welding is generally considered to be the easiest to learn. The gun also feeds out an inert gas such as Argon or CO2 to displace oxygen at the weld site. This means you don’t have any slag to chip away, but you do need a tank and regulator to go with a MIG welder.
TIG
TIG stands for tungsten inert gas welding. Like GMAW, TIG weldinguses a tank and inert gas to shield the weld. In both GMAW and SMAW the electrode is consumed by heat and becomes part of the weld. TIG stands out in that the tungsten electrode carries the arc, but is not consumed. Tungsten withstands the heat of welding. TIG takes the most skill, since you have to hold a filler rod in one hand and the gun in the other in order to accomplish this type of welding. It is usually reserved for specialized types of welds.
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Source: http://en.wikipedia.org
Conclusion
All things considered, SMAW welding is a really simple process which doesn’t need excessive amounts of equipment. Clean your materials, then choose the correct electrode, arc length and weld speed, and you’re starting out on the right foot. Having read through these SMAW welding tips and techniques, you’re armed with everything you need to know – now learning to perfect strong, durable, high-quality stick welds is up to you!
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