Setting out to buy your first welder, or replacing your old one, is not as simple as it used to be. There are several types of welders available, each with their own pros and cons. Deciding between a gas welder and an arc welder, may be the first decision. Even then, arc welders are not all the same, stick welders, TIG, and MIG welders, all use an electric arc to fuse metal. Then there’s inverter welders, not to mention welder plasma-cutter combinations.
Even seasoned metalworkers can have a tough time choosing the best welder (or combo) for their needs. This article is going to provide a complete guide to buying the best welder, along with important facts about welders and welding. For the novice, buying your first welder for a home shop, we’ll start with the basics, discussing the types of welders and how they work.
What welding equipment do you need? Welding safety is an important factor, especially if you haven’t done much welding before. When going through welder specifications, and reading welder reviews, much of the terminology can be confusing if you don’t have detailed knowledge of welders and welding. Before commencing this discussion on welders, it would be advisable to familiarize yourself with the common terms used when comparing welders and welding techniques.
Welding refers to a process whereby materials are fused, or joined, using heat. This usually applies to metals and thermoplastics. Though, generally, welding mostly refers to joining metals and this is going t be the focus of the article. Our first step is going to be defining the terms used when discussing metal welding.
Most modern welders use an electric spark, or arc, to generate the heat needed to join metals. A high amp electric current generates an arc, this melts the metal, thereby fusing two pieces using the molten metal. Because of their popularity, I’ll discuss the types of arc welders in more detail, later in the article.
When talking about gas welding, a clear distinction has to made between a gas flame (oxyacetylene welders), and gas shielding. A gas, or oxyacetylene welder uses a combination of gasses to produce a high temperature flame. This flame can be used to fuse or cut metal. While electric arc welders have become the preferred method of welding, oxyacetylene welders are preferred by some, especially for repairs to engines and transmission systems.
Oil and other debris on a metal surface will disrupt the electric conductivity and need to be thoroughly cleaned before using any type of electric welder. A gas flame will simply burn away any contaminants.
However, oxyacetylene welders tend to produce a less attractive weld and can warp the metal.
Shielding gas can be a combination of gasses or CO₂. The gas is used to prevent airborne contaminants from affecting the quality of the weld.
Stick welders use consumable rods with varying length and diameter. The length of the rod determines how long you can weld for, continuously, before replacing it. A large diameter welding rod is used for thicker material, or harder metals, at a higher amperage. Thin welding rods are used at low amperage for mild, thin, steel. Welding rods can differ in their composition for welding different types of metals.
A roll of wire replaces the welding rod for MIG welders. This wire is fed continuously into the welding gun, allowing the operator to weld, uninterrupted, for longer periods of time. You have more precise control over the weld when using wire. Like welding rods, wire can will have varying diameters for thinner or thicker metals. Likewise, different types of wire are used depending on the metal that is being welded. Welding wire can be used with a shielding gas supplied via a nozzle supplied by a gas bottle, or by means of flux within the core of the wire.
Welding rods or flux core welding wire contain flux, eliminating the need for shielding gas. Flux-coated welding rods are coated with a chemical compound that produces a shielding gas when heated. Welding wire can have a flux in the core, which acts in the same way.
Welders will usually overheat when used continuously at high amps. When the welder reaches its critical temperature, you will have to stop working and allow the welder to cool sufficiently before continuing.
Duty cycle refers to the length of time that a welder can be used at maximum output, before it needs to cool down. This is expressed as a percentage over a 10-minute cycle. If a welder has a rated duty cycle of 70% @ 300A, this means that it can work for 7-minutes at 300 Amperes before it needs cool. It will take 3-minutes for the welder to cool sufficiently, completing the 10-minute duty cycle.
This represents the voltage and amperage produced for a given duty cycle. Higher amps and voltage allow for welding thicker pieces. Metals with a high density, like brass, will require a higher amperage ratio to the voltage.
Flux leaves a layer of black material, protecting the weld from contaminants. This is known as slag and is removed once the weld has cooled. A chipping hammer and wire brush is used to remove slag.
Fine drops of molten metal, called spatter, can be displaced during welding. This creates a rough surface that needs to be cleaned using sandpaper, wire brush, or grinder.
Types of Welders
There are several options when considering an electric (arc) welder. The basic variations are stick welders, TIG welders, and MIG welders. We will also compare inverter welders to the traditional transformer welder.
Stick welders use a flux coated welding rod as an electrode to conduct the electricity and create the arc which melts the metal. Welding rods come in various lengths and diameters. Thicker rods are used at high amperage for hard metals and thick pieces. Welding rods are consumable and need to be replaced frequently, this can be inconvenient when performing long welds.
These are usually the cheapest of all welders. They are simple machines and require little to no maintenance or repairs. Apart from adding transformer oil, too cool the welder, you should be able to use a stick welder for many years, without any running costs.
Mastering stick welding takes some practice. You need to obtain the correct angle between the rod and the metal being welded. Furthermore, a steady hand is needed to maintain the perfect gap between the electrode and the surface being welded. You also need to match the amperage, and diameter of the rod for the type and thickness of the metal being welded. If the amperage is too high, the metal will burn rapidly. Instead of fusing the metal, it will melt holes into it. Amperage that is too low, will cause the rod to stick to the metal.
A stick welder is not as complicated to learn as a TIG welder, but still requires some skill. One of the biggest disadvantages to using a stick welder is that they are not good at joining metal of different types and thicknesses. The main reason why people prefer stick welders is the fact they are cheaper and less complicated than other types of welders.
Tungsten Inert Gas (TIG) welders are more specialized welders and usually used by professionals and robotic welders. These welders use a permeate tungsten electrode to generate the electric arc. A nozzle directs inert shielding gas into the weld to protect it from contaminants.
Although it takes time to master TIG welding, mostly controlling the angle and electrode gap, there are several advantages for certain applications. The tungsten electrode allows for precise welds on thin metals, with reduced burning. A TIG welder is also good on every type of metal. TIG welders Produce little to no splatter or slag. This means a neat weld, without the need to clean it afterwards.
Metal Inert Gas (MIG) welders use a metal wire which is melted into the weld. Inert shielding gas is used to protect the weld. Gas can be deployed from a nozzle at the electrode or can be contained with in the wire (flux core wire).
MIG welding is generally stronger and more ductile than those produced by other welders. MIG welding is also the easiest to learn. The wire feed rate can be adjusted to match the speed at which you are welding. There is no real need to observe the electrode gap or angle. It’s simply a matter of running the wire into the gap between the two metal surfaces at a steady speed.
MIG welding is the preferred method for thin metals, aluminum, and alloys. MIG welders are usually the most expensive.
MIG vs TIG Welding
If you’re having difficulty in deciding between a MIG or TIG welder, here’s a basic summary of the pros and cons of each welding method.
* For the home shop, a MIG welder is usually the best choice.
Traditionally, all arc welders used a transformer with a variety of AMP settings. Modern, inverter welders, use the same basic principle of a transformer with the added benefit of a computer-controlled inverter.
Inverter welders are more efficient and, therefore, use less electricity. This efficiency also reduces the heat produced inside the welder. As a result, inverter welders have longer duty cycles. The monitored current produced by an inverter welder makes them easier to use. Voltage and amperage remain stable, thereby reducing the chance of burning or sticking.
Inverter welders are considerably lighter than traditional transformer welders, making them more portable. While these are robust machines, they are more sophisticated than old-fashioned welders, and may require more maintenance and repairs over their lifetime. Inverter welders are also more expensive to buy.
Welder Plasma Cutter Combos
A lot of people want to know whether they should buy a plasma cutter welder combo.
Plasma cutters are, without a doubt, the best at cutting metal. They use heat to cut through metal with perfect precision. There are no burs or rough edges to the metal, and this means little to no grinding or sanding. A plasma cutter will be limited to thickness (or density) of the metal it can cut. This will be determined by the power of the electric arc generated by the plasma cutter. Most plasma cutter welder combos will be limited in their power. However, one machine that does both jobs can be tempting, especially for the DIY metalworker or hobbyist.
Professional metal workers prefer separate machines for cutting and welding. This is mostly due to the fact that you can only perform one task at a time. With one machine for both cutting and welding, you can’t do both simultaneously. Since time is money in a professional metal shop, you will usually have people performing both tasks at the same time.
In home shop, it is understandable why people may see a welder plasma cutter combo as the ideal solution. One machine will take up less space, which is often a big concern in a home or garage shop. It is also cheaper to buy the two-in-one option, instead of buying two separate pieces of equipment. Though, in this regard, you need to pay attention to what you’re buying.
Cheap welder plasma cutters are generally inferior. They can be less proficient when welding and may not have the power to cut, or weld, thicker denser metals. With that said, a good quality welder plasma cutter can be the perfect solution for the home shop.
Cutting metal goes hand in hand with welding. The benefits of plasma cutter, especially when doing complicated cuts, cannot be overlooked. If you feel the need the to buy a plasma cutter and welder, and don’t need to use both at the same time, a welder plasma cutter combo makes perfect sense.
If you’re going to buy a welder plasma cutter combo, do your homework. Be prepared to pay more for a quality machine, this will still be cheaper, and probably more convenient, than buying individual machines. Read the reviews and pay attention the power and duty cycle of these machines, it can make all the difference.
What Type of Welding Equipment Do You Need?
Regardless of what type of welder you choose, there is quite a list of other essential items. Safety gear is vital, I’ll be discussing this under the heading Welding Safety. Along with this, there are essential tools that are needed for metal work. Welding is only part of the process, you will also need to cut metal and, possibly, bend metal too.
A basic welding tool arsenal has to include a chipping hammer and a wire brush. A chipping hammer has a flat head with a sharp point at the other end. This is used to chip away the slag that is left behind by welding flux. A wire brush is also used to clean away slag and can help in removing splatter.
An angle grinder is another must-have tool for welding and metal work in general. It can be used to cut metal but has limitations when cutting sharp corners and curves. An angle grinder is important for cleaning the metal after the weld has been completed. Angle grinders are used to cut away ridges in the weld and generally smoothing off the metal surface.
A bench vise with an anvil is an important tool in any shop. It holds the workpiece in position and most have an anvil for beating metal into shape. A bench vise can also be used for bending metal with square corners. Though for more controlled bending, like precise curves, a bending tool is better.
A selection of hammers for beating and knocking metal into different shapes should be on your list. A ball peen hammer is probably the most important. C-clamps are needed to hold pieces together while welding and squaring tools can be a great aid in ensuring perfect right angles. I particularly like magnetic squares. These tools have a 90-degree and 45-degree angle. Being magnetic, they hold two pieces of metal at the correct angle without any need to fasten or make adjustments.
The importance of safe working practices when welding cannot be over emphasized. You are dealing with extremely high temperatures, and molten metal falling from the workpiece is hazardous in many ways. Then there’s the ultraviolet radiation that can cause long term, irreversible damage to your eyes and skin.
Welding PTFE is essential, and this starts with a welding helmet. Invest in a quality welding helmet to protect your eyes and face from the effects of ultraviolet light. An auto-darkening welding helmet, with a high level of UV protection, is something that you will come to appreciate.
Hot metal can burn through clothing, so wear fire resistant materials. You need to cover every part of the body with thick material to prevent UV damage to your skin. Long sleeves (of a tightly woven material) and thick denim pants are the recommended clothing.
Thick leather gloves will protect your hands from burning. Thick, fire resistant work boots are also essential. Falling drops of molten metal can lie and smolder on your boots, which is obviously dangerous.
Work in an uncluttered environment and make sure that you never weld in close proximity to flammable materials. Electric welders should never be used in wet or damp conditions. Adequate ventilation is important, as toxic gasses are emitted.