Anyone new to welding will be astounded by the wide variety of equipment used. To recap, welding (in most forms) is the process of fusing two metal workpieces together using heat created by an electric arc. This is provided by an arc welding machine. And, just as there are different welding processes, there are also different welding machines. Each is suited for welding different types of metals and in different settings and conditions. Choosing your first welder can be a painstaking process, but this guide should make that purchase easier.
Types of Welders
Welding machines are categorised by the welding process. Metal Inert Gas (MIG) welding is often used when fusing steel, stainless steel, or aluminium workpieces with heat created by the MIG arc welder and the welding electrode (in the same material as the metal). This takes the form of a wire and is fed from the welding machine, making for a simplified process and smooth welds. A shielding inert gas can also be used.
Tungsten Inert Gas or better known as TIG arc welders use a non-consumable tungsten electrode that, unlike MIG welding, doesn’t form part of the weld pool. Instead, this stabilises the electric arc and is valuable when using different polarities. TIG welders need to achieve very high temperatures and power outputs in order to get clean and exceptionally strong welds in non-ferrous metals like magnesium and copper and their alloys.
They are also the equipment of choice when welding thinner pieces of aluminium. To shield the weld pool from contamination, Argon gas is used. Lastly, Stick or Shielded Metal Arc Welding (SMAW) involves the heat generated from the welder and the use of an electrode. This is one of the oldest forms of welding and is particularly useful in fusing thicker pieces of ferrous metals, especially cast iron.
This is a simple, general-purpose welding process, that omits the use of separate shielding gases, and instead relies on the flux-cored electrode to shield the weld from impurities. Welds are strong, though the excess spatter from the melted electrode means more work in producing cleaner results. There are also combo welders that combine two or more welding types, meaning versatility in terms of metals and workpiece thicknesses. MIG and stick, and TIG and stick arc welders are the most common.
How Do Metals and Metal Thickness Impact the Choice of Welder?
Choosing a welder then depends on the type of metals you’ll be working with and how thick they are. Go for a TIG welder if you’re constantly using non-ferrous or exotic metals in your line of work. For metals with high melting points like titanium or platinum, they’re the only choice. TIG arc welders have foot controls to fine-tune amperage adjustments and to get clean, neat welds in thinner pieces of metal. Mind you, a TIG welder can also be used in ferrous metals, but at a slower rate. This versatility and high-power output make them one of the pricier machines around.
MIG welders using flux-cored electrodes provide a quick alternative in ferrous metals as well as copper and aluminum alloys. Thicker workpieces, especially those in iron, are handled with a stick arc welder. These are also some of the more affordable welder variants.
What to Look for in Your Next Welder?
Amperage varies across the different types and tiers of machines. The more the amperage the easier and quicker the welder will achieve the required heat in the arc. Generally, for smaller repairs in the shed or garage, a welder with 100 amps will be capable of fusing metals that are an inch thick. One with more amperage will make that task easier and give you access to thicker workpieces and hence more usability. The higher you go on the amp chart, though, the higher the cost of the welding machine.
A typical welding session is 10 minutes. Duty cycles refer to the percentage of those 10 minutes at full amperage. A 150-amp machine with a 30 percent duty cycle can churn out all of its 150 amps for a full three minutes before it needs to cool down or you risk overheating. Depending on what you’re welding, this can be more than enough time to complete the task. Duty cycles then affect the speed at which you can weld. Of course, you can choose lower amperages in thinner metals and those with lower melting points.
Where the Welder Will be Used
While a TIG arc welder is suitable for most metals, this needs to be used in controlled settings void of wind and rain. MIG welders that use a flux-cored wire are a good alternative, but nothing beats stick arc welders for welding in adverse outdoor conditions. The fact that there’s no gas involved means the equipment is also easier to lug around. And much safer at that!
If you’re buying your first welder, then the included accessories can save you some cash. Then again, buying welding accessories separately will cost more, but you do have the choice of handpicking exactly what you need and want. Bundled kits will have torches, hoses, regulators, valves and clamps, and all the basics (apart from gas bottles and safety gear) to get you welding sooner.