Spot Welding: What is it & How it Works

Key Points

- Spot welding, also known as resistance spot welding, is a technique that joins metal surface points together using electrically produced high heat and pressure, leaving a tiny spot where the materials are joined. This method is widely used in industries such as automobile manufacturing, electronics, construction equipment and healthcare technology.

- The process of spot welding involves using copper alloy electrodes to carry an electrical current through metal points being welded together, generating pressure and heat to join the metals. Once the electric current is turned off, the lack of pressure and heat allows the welded point to harden, creating the joined spot.

- Spot welding offers several benefits, including learnability, cost efficiency, versatility and minimal damage to thin metal sheets. It is considered one of the easier welding techniques to pick up, especially with proper training, and is ideal for projects involving thin metal sheets due to its precision and reduced risk of damaging the materials.

- Universal Technical Institute (UTI) offers a 36-week Welding Technology program that provides education and hands-on training on four major welding processes: Gas Metal Arc Welding (GMAW), Shielded Metal Arc Welding (SMAW), Gas Tungsten Arc Welding (GTAW) and Flux-Cored Arc Welding (FCAW). This program prepares students for entry-level spot welding careers by teaching them essential welding skills in state-of-the-industry labs.¹

 - The demand for skilled welders is high, with an estimated average of 42,000+ annual welding job openings in the U.S.⁴² and total welder employment expected to exceed 437,000 by 2032.⁵⁰ UTI's Welding Technology program, developed in collaboration with Lincoln Electric, aims to equip students with the necessary skills to meet industry needs and pursue fulfilling careers in spot welding.

Welding can be a fantastic career, and spot welding is no exception!

It’s a technique often used in the manufacturing of automobiles and electronics. Spot-welded metalwork is also used in construction equipment, machinery and building materials to complete building projects. This welding method also helps create medical devices and tools, making spot welding critical in manufacturing health care technology.

These are only a few of many industries that need spot welding. Here are some stats on welding careers:

• 42,000+ estimated average annual welding job openings in the U.S.⁴²
• Total welder employment is expected to exceed 437,000 by 2032.⁵⁰

But if you don't know what spot welding is, you probably don't know if it's the right career for you.

Get ready to read! We'll explain spot welding, including how it works, why it's important and how you can train for a spot welding career at Universal Technical Institute.¹

What Is Spot Welding?

Welding refers to the process of transforming and joining metals using high heat and pressure. Spot welding — also known as resistance spot welding — joins metal surface points together using electrically produced high heat and pressure. This welding method is known as spot welding because it leaves a tiny spot where the metal sheet materials are joined.

Read more: What Is Electric Welding?

How Spot Welding Works

How does a spot welder work? Let’s dig into what happens during a spot weld.

• Copper alloy electrodes carry an electrical current through metal points being welded together. The electric current generates pressure and heat.
• Pressure and heat successfully join metals. The electric current is then turned off.
• Resulting lack of pressure and heat allow the welded point to harden and create that joined “spot.”

Spot welders, for the most part, need only sheet metal and a piece of spot welding technology, like a handheld spot welding gun or a large spot weld machine. In some cases, they may need the resources of an entire spot welding technology facility.

Then there are copper alloy electrodes and metal materials commonly used for spot welding, such as sheets of steel, stainless steel, titanium and nickel alloys. Many modern facilities will also need spot welding technicians to use digital software to help with their jobs, especially if the process is automated.

Read more: Welding Blueprint Symbols: What Are They, and How Do You Read Them?

How does a spot welder join metal together?

A spot welder joins metal together by using a process called resistance welding, which relies on the heat generated by electrical resistance to fuse the metal parts. The process is typically very fast, which is why it’s commonly used in industries like automotive manufacturing where things need to be joined together quickly and efficiently.

How To Use a Spot Welder

Learning how to spot weld is a straightforward process, but safety and precision are key to achieving strong welds. It’s recommended to get formal training before attempting to spot weld. This is how you can use a spot welder effectively if you have foundational knowledge:

• Gather required materials: Make sure you have your spot welder, metal pieces and safety gear handy. Safety gear should include glasses, gloves and a welding helmet that can protect you from heat, sparks and UV radiation.
• Prepare the metal surfaces: Clean the surfaces of the metal pieces to be welded. Ensure the metal sheets are in good contact with each other to create a solid weld.
• Set up the spot welder: Adjust the settings based on metal thickness. Position the electrodes and place two metal pieces between the welder’s electrodes.
• Align the metal sheets: Clamp the metal pieces together in the exact position you want to weld.
• Activate the welder: Apply pressure to the electrodes using the welder’s handles. Trigger the welding process by engaging the machine and hold the pressure until the weld cools and solidifies, which typically takes a second or two.
• Inspect the weld: Once the process is complete, inspect the weld to ensure it’s solid and consistent. Test the joint by gently pulling the metal pieces to ensure a strong connection.
• Repeat the process: Continue spot welding along the joint line, making sure each weld is evenly spaced.

Spot Welding Uses

Spot-welded metalwork is everywhere.

If you drive a vehicle, you likely operate machinery made with spot welding. Have you been indoors today, including at home? Well, some of the materials used to create the buildings surrounding you were most likely spot welded.

Buildings, machinery, electronics, appliances and other assets and goods almost always require some welding, and large welding projects almost always include spot welding tasks. That is why spot welding projects are so versatile and why welding technicians can pursue different types of spot welding careers.

Benefits of Spot Welding

Spot welding has distinct advantages that set it apart from other welding methods.

Learnability

Once you understand the fundamentals of welding and have practiced using these skills, learning to spot weld isn’t too hard. In fact, it’s seen as one of the easier welding techniques to pick up, especially once welders adequately learn how to use a spot welder. This process can even be automated with machinery, although it still needs to be supervised by a trained spot welding technician.

Of course, to learn these fundamentals, you need the right instruction. A program like UTI's 36-week Welding Technology program can provide education and hands-on training on four major welding processes. Opportunities like these can get help you learn how to use a spot welder as soon as possible!

Cost Efficiency

Spot welding metal materials are thin and lightweight. That also means they're less expensive and can be welded much faster, allowing welders to complete more revenue-generating projects more quickly. Aside from the spot welding technology and the metal materials used, there aren’t usually any other materials to add to the final cost.

Versatility

Welding different metals is typically difficult since all metals react differently to pressure and heat — a problem that gets even more challenging the thicker the metal materials are. On the other hand, metal sheets used for spot welding are thin enough to weld with relative ease. This increases the method's versatility and the projects it’s used for.

Minimal Damage to Thin Metal Sheets

Because spot welding is specifically done on thinner metal sheets, it’s uniquely ideal for manufacturing processes that need parts made of these materials. Other welding techniques could easily apply too much pressure and heat, damaging them. They could also clumsily weld the joint spots, resulting in metalwork with poor structural integrity.

Welding Training at UTI

UTI's Welding Technology training program teaches students these essential welding skills in less than a year:

• Gas metal arc welding (GMAW), also known as MIG welding.
• Shielded metal arc welding (SMAW), also known as stick welding.
• Gas tungsten arc welding (GTAW), also known as TIG welding.
• Flux-cored arc welding (FCAW).

These skills are taught in our state-of-the-industry labs, with all the necessary equipment and tools students need to train. If you take welding courses, you can use these resources yourself, which will teach you how to use the same or similar resources that welding facilities use. This will help make it easier to complete spot welding tasks and adjust to the workload if hired as an entry-level welder.

Students who complete our program also receive a diploma or certificate! Our program was developed in collaboration with Lincoln Electric, a relationship that helps ensure the curriculum matches industry needs.

Read more: How to Become a Certified Welding Inspector

Build Skills at UTI to Prepare for a Spot Welding Career!

Enroll with us today if you're ready to take the first step toward a spot welding career! UTI’s 36-week Welding Technology program teaches students essential welding skills to prepare them to become entry-level spot welders. UTI's brand relationships can also help graduates when they pursue jobs where they can put these valuable skills to use.

We have campuses nationwide that host our welding program. When you’re ready to start learning, apply to our welding school!