Whether you are a DIY welder or interested in pursuing a career in welding, you can get started with this ultimate guide to welding.
Welding appears to be a straightforward process of joining together two pieces of metal with molten material. As simple as it may sound, it entails using a variety of welding techniques.
The most common welding class is arc welding. Arc welding is the most basic form of welding and this where all novices must start.
Since arc welding is a category, it encompasses a number of welding methods, such as stick welding, metal inert gas welding and tungsten inert gas welding. These welding methods are convenient and widely used in the industry.
Here is a thorough breakdown of these welding methods.
Stick welding is also called shielded metal arc welding or SMAW. It is one of the oldest and widely used welding techniques due to its simplicity. Unlike TIG and MIG welding that use gas cylinders, it is not affected by the wind. This makes it a popular choice for outdoor welding.
Welders perform stick welding by creating an electric arc between the workpiece and metal electrode. The electric current that goes through the electrode melts it so that a weld pool is formed on the workpiece. The electrode has a flux coating, which melts down to safeguard the weld pool from corrosion and contamination from the environment. This is similar to how shielding gas protects the weld in TIG and MIG welding.
The flux melts to form a slag layer over the weld bead. This protective layer should be chipped off once the weld has cooled down.
The following are the main benefits of stick welding.
- This method of welding is portable. Stick welding can be done on relatively thick metal sections. The equipment is not particularly heavy; hence, it can be transported easily to different locations. There is no need for a wire feeder or any other extra equipment, such as a gas cylinder.
- Stick welding is one of the most suitable choices for outdoor welding. Welding with gas is not feasible for outdoors, especially under strong wind conditions.
- Although it is easier to learn as compared to TIG welding, mastering stick welding requires a certain level of practice.
- Stick welding can be performed even if the surface is not perfectly clean. It can be done on metal surfaces that have some rust or mill scale.
- Stick welding requires a greater level of skill as compared to MIG welding since the electrode must be kept at a certain distance from the workpiece while it melts down.
- Stick welding generates a lot of slag and spatter, which can make the process difficult.
- There may be a decrease in efficiency due to the necessary cleanup of slag.
- The weld produced is not as reliable or of high quality as the TIG weld.
Before welding, remember that the most important consideration is your personal safety. This should be given higher priority than anything else.
For any welding equipment that you have deployed, you should always refer to the user manual before using it. Pay full attention to the safety instructions provided by the equipment manufacturer.
You must have suitable safety equipment at hand to protect yourself against ultraviolet rays, heat and sparks generated by the arc. Make sure to protect your body with a long-sleeved garment made from fire-retardant material. Wear safety glasses and a helmet to protect your eyes and head.
Heavy fumes are emitted by the flux during stick welding. Hence, there must be satisfactory ventilation in any area where you are performing stick welding. If you are stick welding outdoors, then you do not need to worry too much about ventilation.
But in enclosed spaces, proper ventilation is an important safety measure. You should deploy an exhaust so that it draws out the fumes from the environment.
As a beginner, you can utilize a multipurpose welding machine. This will allow you to practice different types of welding techniques, such as stick, TIG and MIG. You can also buy a dedicated stick welder, which will be much more economical.
The ground clamp is also available with the welding machine. You should plug the ground clamp into the welding machine and clamp it onto the metal section being welded.
Stick welding will cover your workpiece with slag, which must be chipped off when the welded section is cool enough. You can chip away at the solidified slag with a slag chip and hammer.
For a better surface finish, you can scrub the welded part where you chipped off the slag with a wire brush.
A multitude of stick welding electrodes are available in the market. You must choose the most appropriate electrode, according to the needs of your project. Some of the most commonly used welding electrodes include 7018, 7024, 7014, 6013, 6012, 6011 and 6010.
If you are welding with mild steel, then you can utilize any E70 or E60 stick electrode. The 6013 is a fine option for beginners, although the 7018 is extremely popular on account of its welding strength.
In order to comprehend the welding electrode you require, you must know what the 4 digits mean.
The first 2 digits indicate the lowest tensile strength. For instance, an electrode that starts with the number 60 means that its tensile strength is 60,000 psi. This number must match the strength property of the base material.
The 3rd digit indicates the positions for which the welding electrode may be used. Number one means that the electrode is capable of being used in any position. Number 2 means that you should use the electrode only in a flat position.
The 4th digit indicates the current that may be employed for the electrode, as well as the electrode coating. Here is a breakdown of the digits. The digits are followed by the type of coating. The weld current type is indicated in brackets.
0 – cellulose sodium (dcep)
1 – cellulose potassium (dcen, dcep, ac)
2 – titania sodium (dcen, ac)
3 – titania potassium (dcen, ac)
4 – iron powder titania (dcen, dcep, ac)
5 – low hydrogen sodium (dcep)
6 – low hydrogen potassium (dccep, ac)
7 – iron powder iron oxide ( dcep, ac)
8 – iron powder low hydrogen (dcen, dcep, ac)
Setting up a stick welder is a fairly straightforward task as the equipment itself is quite simple compared to other kinds of welders. Keep in mind that the settings for polarity are influenced by the type of electrode that you are using for the project. Always make sure that you double check whether DC+/DC-/AC is involved.
For practice, you can begin with 6013 electrodes using dcen on a steel plate with a thickness of about 3/16 inch.
After you have set up the welder, according to the user manual, it is time to begin welding. Double check to ensure that all settings are correct. Once that is done, you can position some scrap metal pieces with 3/16 inch thickness to create a butt weld.
Since stick welding requires a fair bit of skill, it is highly recommended that you first practice on scrap steel pieces and then move to welding projects. Keep practicing till you are comfortable and feel confident about stick welding.
Striking electrode to create an arc is often the most difficult part of the process. You can master this step with plenty of practice. The rest of the welding process is quite simple.
MIG welding is also known as gas metal arc welding or GMAW. Mig itself stands for metal inert gas.
Mig welding is very popular because it is the easiest welding procedure for beginners. It is well- suited for welding auto parts and home repair projects. Mig welding is often used for joining low-alloy steels.
In MIG welding, an arc is created between the wire electrode and the metal workpiece. This melts the wire electrode gradually, which is used to create the weld joint.
You can easily and accurately feed the wire electrode with an electrode gun, which is linked to a MIG welding machine. The MIG gun also releases controlled amounts of shielding gas to safeguard the weld pool from contamination.
One of the greatest benefits of MIG welding, in addition to its ease of use, is high productivity and low cleanup. You save plenty of time since you do not have to replace electrodes or chip away at the slag. Mig welding, therefore, has considerably higher productivity than stick welding.
You can purchase a reliable MIG welding machine for less than $500. A good choice is the Hobart 500559 MIG welder. You must then spend a small amount on gas and wire electrode to get started with MIG welding. Due to the increased productivity mentioned above, welding costs will be further reduced. This is ideal for small businesses.
Anyone can learn to weld with this technique right away. As a result, MIG welding is the top choice for hobbyists and home welders. You can set up a MIG welding machine in a few minutes and get started.
The MIG welding method employs shielding gas to safeguard the weld pool from getting contaminated by the environment. The end result is a reliable and clean weld joint. You don’t need to chip away any solidified slag. The weld is also very accurate since you can use both hands to control the MIG welding gun. You can also change the feed rate by adjusting the voltage, which makes this a very versatile and flexible process.
You must fit the MIG wire within the welder properly, so that the machine can feed it through the welding gun into the joint.
Your welder may have a roll of flux cored wire. For MIG welding, you will need a thicker wire for joining thicker metal sections.
For the best quality welds, you should use the thinnest wire. Here are some guidelines for selecting welding wire.
0.23 inch wire – this is suitable for only small MIG welders and welding thin gauge metal sheets ranging from 16 gauge to 24 gauge.
0.3 inch wire – MIG welding machines often come with wires of this thickness. This wire is suitable for welding sheets up to 1/8 inch.
0.35 inch wire – this wire is a good selection for beginners. It is suitable for welding metal sections up to ¼ inch thick.
0.45 inch wire – this is often the best choice for industrial welding since a wire of this thickness is sufficient for metal sections that are more than ¼ inch thick.
MIG requires shielding gas to protect the molten weld from corrosion while it is hot. Here is a brief guide on the important features of shielding gases and how you should select them for your projects.
porosity simply refers to holes that are created within the weld. You would want to avoid this defect since the holes weaken the weld, thereby making it unreliable.
Quite often, it is gases in the atmosphere that lead to porosity. Shielding gas is, therefore, used to keep the weld safe from the adverse effects of the atmosphere. If shielding gas is not used, then the weld will react with nitrogen and oxygen from the atmosphere, which will make it porous.
If you are using flux-cored welding wire, then you do not need to worry since the core releases shielding gases that protect the weld pool.
It is best to ensure optimal flow of shielding gas from the cylinder to ensure a strong and reliable weld that is free from porosity. Releasing too much gas is not a good idea as it can lower the temperature of the molten weld. You must strike a balance between sufficient gas flow and high temperature.
A good way of ensuring this is to keep your hand at a 3-inch distance from the nozzle tip. Turn up the gas flow. Ideal gas flow is when you just begin to feel the flow of gas on your hand.
Here are the most commonly used shielding gas mixtures.
You should not employ pure argon for welding steel. This gas is suitable for non-ferrous metals, for instance, aluminum. Argon is characterized by a low value for thermal conductivity. This will lead to a narrower bead. Although you will find good penetration in the middle of the weld, there may not be enough penetration in other regions of the weld. Hence, it is not effective for steel.
Carbon dioxide gas is a fine choice because it is much cheaper than argon. Thus, it is widely preferred by MIG welders.
However, carbon dioxide has one major issue. The arc produced can be quite wide and less stable. This will produce a lot of spatter.
An appropriate mix of carbon dioxide and argon can produce the highest quality weld. The properties of the arc lie midway between pure carbon dioxide and pure argon. The arc has the right width, good penetration and minimal spatter.
Here are the most common movements employed for MIG welding.
Pushing the weld using forehand position is the most common MIG welding technique. To reach an optimal position for MIG welding, you must place the weld gun at a 10-degree angle. The electrode should face the direction you intend to weld. You can further decrease the angle in order to alter the shape of the weld bead.
Once the welding gun is at the correct orientation, squeeze the trigger and move the MIG gun slowly. Push the nozzle forward in the welding direction.
In this position, you move the welding gun toward your body using backhand position. Use the same angle described above. This technique produces higher penetration than when you are pushing the electrode.
TIG stands for tungsten inert gas welding. In this welding process, you will use a tungsten electrode to create an arc that heats up metal to its melting point. Shielding gas is directed at the weld pool to keep it safe from the atmosphere. Tig welding is known for producing the highest quality welds.
Since TIG welding requires the operator to hold the TIG torch in one hand and feed filler material with the other hand, it is the most difficult welding process to master since higher manual dexterity and the concurrent use of both hands is required.
Tig welding is done with the help of tungsten electrodes, which are non-consumable and very stable. A filler material may be required, which is fed by hand. Shielding gas protects both the weld pool and the electrode from corrosion. Tig welding produces precise welds and it can be used for the widest range of metals.
Tig is a very versatile welding method since it is suitable for a wide range of metals like stainless steel, steel, nickel alloys, aluminum, chromoly, copper, magnesium, bronze, brass and gold as well.
Since it does not rely on flux material, there is no danger of corrosion created from flux entrapment. No slag is created. This eliminates post-weld cleaning. Moreover, no sparks or hazardous fumes are created in this process, making it a safer alternative to MIG and stick welding.
As TIG welding creates clean and high-quality welds, it is most suitable for applications where appearance matters. There is no splattering involved since a relatively small amount of filler is required.
Thanks to the desirable thermal properties of tungsten, an arc can be maintained, which can go up to temperatures of 11,000 degrees Fahrenheit. Excellent thermal conductivity and high melting point prevent tungsten from melting. Tungsten also has a much higher tensile strength as compared to steel.
TIG welding is carried out in 2 modes: automatic and semi automatic. In the semi-automatic mode, the welding operator configures gas flow and current settings. The operator then controls the filler rod and the tungsten electrode.
In automatic mode, the operator configures the gas flow rate, arc length, filler rod position and travel speed. They then observe the operation as it progresses and intervenes only when required.
Tig welding can be carried out with both ac and dc supplies with the current ranging between 15 and 350 amperes.
To perform TIG welding, the operator must first turn on gas flow from the cylinder. This gas flow can be regulated by the valve located on the TIG torch. The torch should be held above the welding area without touching it. The operator must press the foot pedal so that an arc is developed between the tungsten electrode and the workpiece. This melts the filler material, which then creates a weld pool on the workpiece. A weld joint is created when the weld pool solidifies after cooling.
However, for all its benefits and high-quality welds, TIG welding is a much slower process than stick and MIG welding. It is, therefore, used where high quality welds are of utmost importance, despite the low speed of this process.
TIG welding equipment is often more expensive than stick and MIG welding. You can purchase the Everlast PowerTIG for under $1,000.
Different torch sizes are available with varying current capacities. The torch case holds the electrode and gas nozzles.
High currents can lead to high temperatures. A water cooling system prevents the torch from being overheated. This cooling system is much more efficient than air cooling, but it requires additional maintenance.
Surface oxide formation is a cause for concern in TIG welding of magnesium and aluminum alloys. In aluminum welding, an arc is developed between dissimilar metals (tungsten and aluminum), which means AC can be converted to DC. A DC suppressor prevents this undesirable conversion.
Tungsten has a very high melting point of about 3000 degrees Celsius, making it highly suitable for TIG electrodes. It also has great electrical and thermal conductivity. For longer electrode life and enhance arc stability, 1 to 2 percent of zirconium and thorium are mixed with tungsten. The diameter of the electrode is also influenced by current polarity.
These nozzles are made from a thermal-resistant ceramic material to withstand high welding temperatures. Various nozzle shapes are available for all kinds of welding tasks.
This feature minimizes the turbulence in gas flow. Turbulent gas flow may not deliver the best results. Hence, a gas lens is employed for smooth gas flow that will protect the weld pool.
The ‘high frequency start’ feature is available on more advanced TIG welders. With this feature, there is no need to strike the electrode with the workpiece in order to create an arc. The high frequency start allows you to create a welding arc even when the electrode is an inch away from the workpiece. This significantly simplifies welding because striking the electrode to create an arc is quite tricky.
After the arc is developed, the current and voltage drop back to normal operational settings. This automatic regulation of the voltage and current prevents the tungsten electrode from getting consumed.
Novice welders should begin by practicing on scrap metal due to the number of functions in TIG welding, such as feeding filler metal, holding the torch correctly and controlling the foot pedal.
You should hold the torch at an angle of around 75 degrees. Make sure that you maintain a distance of ¼ inch to 1/8 inch between the electrode and workpiece.
Now that you are familiar with welding, why not embark on this exciting and rewarding career? It is a well-paying technical trade that does not require a college degree. Moreover, the outlook is bright as the demand for welders will keep increasing in the future.