THE DIFFERENCES BETWEEN WELDING, BRAZING AND SOLDERING

The primary job of a welder is to join parts using tools that generate intense heat. On the surface, this may seem like a simple concept — but anyone who knows the welding industry knows that there are many different techniques and ways this can be done.

To effectively join parts together, a welder will solder, braze or weld the two materials — which are all processes that utilize heat. While these three methods have a lot in common, there are distinct differences that are important to know.

Welding, brazing and soldering are each suited for different types of metals and applications and involve different skills, gear and equipment. Keep reading to learn more about their similarities and differences:

What Is Welding?

Welding is a fabrication process that joins two or more parts by means of high heat, pressure or both. It melts the parts together and allows them to cool, resulting in fusion. Welding is typically used on metals and thermoplastics, but can be used on wood. Filler materials, which are extra pieces of metal, are often used to seal any gaps.

The bond created by welding can withstand all kinds of stresses, such as supporting the body of a car or plane. With welding, the two metals must be similar (i.e. you can’t weld steel to copper). The temperature must be very high to join the two pieces together, yet not too high, as this can change the characteristics of the metal and cause the weld to weaken.

No two welding projects are exactly alike. Different types of welding are used based on materials and desired outcome. There are over 30 different types of welding, however, there are four methods that are most commonly used: 

1. Gas metal arc welding (GMAW): Also known as MIG welding, in GMAW, an electric arc is formed between the metal and a wire electrode, which applies heat to the metal pieces. This fuses and melts the parts together, forming a permanent bond.
2. Shielded metal arc welding (SMAW): Also known as flux shielded arc welding or stick welding, SMAW forms the weld with a flux-coated electrode, which is a rod or metal stick held in an electrode holder connected to a power source. Electricity passes through the electrode and touches the base metal, while a gas is formed by the flux that shields the electric arc between the metal being welded and the electrode.
3. Flux-cored arc welding (FCAW): An electric arc unites a continuous filler metal electrode with the base material. As the welding process happens, the shield gas provided by the flux protects the weld pool from oxidation and other elements in the atmosphere.
4. Gas tungsten arc welding (GTAW): Also known as TIG welding, GTAW uses a non-consumable tungsten electrode in the welding process. The tungsten and weld puddle are protected and cooled with an inert shielding gas such as argon or helium, and the tungsten electrode heats up the objects in order to form a bond.

Read: Welding History Goes Back Farther Than You Think

What Is Brazing in Welding?

Brazing is a process in which metals are joined by melting a filler metal into the joint to create strong permanent bonds. Brazing requires a small joint spacing to allow capillary action to draw the filler metal into the joint when the parts reach the proper phase temperature above 840°F (450°C).

Brazing uses flux to strengthen and improve its mechanical properties. Fluxes used in brazing have three major functions:

• They remove any oxides that form as a result of heating the parts.
• They promote wetting which is the phenomenon whereby a liquid filler metal or flux spreads and adheres in a thin, continuous layer on a solid base metal.
• They aid in capillary action by pulling the molten alloy into the joint.

Flux flowing into a joint reduces oxides to clean the surfaces and gives rise to a capillary action that causes the filler metal to flow behind it. Fluxes are available in many forms, such as solids, powders, pastes, liquids, sheets, rings and washers.

Flux and filler metal combinations are most convenient and easy to use. Using excessive flux in a joint may result in flux being trapped in the joint, weakening the joint or causing the joint to leak or fail.

The American Welding Society’s classification system for brazing alloys uses the letter B to indicate that the alloy is to be used for brazing. The following letters indicate the atomic symbol of metals used to make up the alloy, such as CuZn (copper and zinc). There may be a dash followed by a letter or number to indicate a specific alloyed percentage. The letter R may be added to indicate that the braze metal is in rod form. 

Unlike welding, brazing can be used to join dissimilar metals, such as gold, silver, copper and nickel. While brazed joints are strong, they are not as strong as welded joints.

What Is Soldering?

Soldering is a process in which metals are joined by melting a filler metal into the joint to create strong permanent bonds. Soldering may or may not have capillary attraction and is done at a temperature below 840°F, much lower than welding. This process allows for different metals to be soldered, including copper, brass and gold, just to name a few.

Like brazing, soldering uses flux to strengthen and improve its mechanical properties. 

Soldering methods are grouped according to the method with which heat is applied: torch, furnace, induction, dipped or resistance. Soldering alloys are usually identified by their major alloying elements. The below chart lists the major types of solder and the materials they will join.

While soldering may seem similar to welding, it serves a different purpose. Typically, a solder is soft and comes in tubes and reels. It’s often used in electronic devices, as it allows the parts to connect electronically. In general, a soldered bond isn’t as strong as one that has been brazed or welded—however, it allows for pieces to conduct electricity.

Soldering vs Welding

Soldering is classified by the American Welding Society (AWS) as liquid-solid phase bonding processes. Liquid means that the filler metal is melted, and solid means that the base material or materials are not melted.

Unlike welding, soldering does not involve melting the work pieces. The main difference between soldering and welding is the heat source. Soldering is applied via torch, furnace, induction, dipped or resistance as heat sources taking place at a temperature below 840°F (450°C), whereas arc welding uses electricity as a heat source reaching temperatures of roughly 10,000 degrees Fahrenheit.

Brazing vs Welding

Brazing is also classified by the AWS as liquid-solid phase bonding processes. Liquid means that the filler metal is melted, and solid means that the base material or materials are not melted.

Unlike welding, brazing does not involve melting the work pieces. The main difference between brazing and arc welding is the heat source. Brazing is applied via torch, furnace, induction, dipped, or resistance as heat sources occurring at a temperature above 840°F (450°C) whereas arc welding uses electricity as a heat source reaching temperatures of roughly 10,000 degrees Fahrenheit.

Brazing vs Soldering

The only difference between soldering and brazing is the temperature at which each process takes place. Soldering takes place at a temperature below 840°F (450°C), and brazing occurs at a temperature above 840°F (450°C).

Advantages of Brazing and Soldering

Some advantages of brazing and soldering as compared to other methods of joining include the following:

• Low temperature
• May be permanently or temporarily joined
• Dissimilar materials can be joined
• Speed of joining
• Less chance of damaging parts
• Slow rate of heating and cooling
• Parts of varying thicknesses can be joined
• Easy realignment

Brazing and soldering are processes that have many great advantages, but are often overlooked when a joining process is being selected. The ability to join many different materials with a limited variety of fluxes and filler metals reduces the need for a large inventory of materials, which can result in great cost savings for a small business, home shop or farm.

How This Applies to a Career in Welding

It’s important for today’s welders to be familiar with welding, soldering and brazing. As mentioned, no two projects are exactly alike — and different materials and specifications require different methods to achieve the desired result.

Skilled welders are able to look at a project blueprint and determine the best method for completion. They’re able to adapt to different situations and are continuously educating themselves on different materials and techniques in order to improve their craft.

Many of today’s top employers prefer to hire welders who have completed a formal training program, like the Welding Technology training program at Universal Technical Institute (UTI).¹

Created in conjunction with Lincoln Electric, this program teaches students everything from welding safety to the four common types of welding to pipe welding. Students are able to safely practice using VRTEX^® virtual welders, and train with some of the same tools and technology used by welders in the field today.

Train to Become a Welder in Less Than a Year

UTI’s Welding Technology training program equips you with the hands-on training needed to become a welder in just 36 weeks. You’ll learn the four major arc welding processes used in the industry: gas metal arc welding (GMAW), shielded metal arc welding (SMAW), flux-cored arc welding (FCAW), and gas tungsten arc welding (GTAW).

Welding Campus Locations

If you’ve decided that UTI’s Welding program is the right fit for you, there are several campus locations you can choose to attend. The campuses nationwide are located in:

• Avondale, Arizona
• Long Beach, California
• Rancho Cucamonga, California
• Miramar, Florida
• Lisle, Illinois
• Bloomfield, New Jersey
• Mooresville, North Carolina
• Exton, Pennsylvania
• Austin, Texas
• Dallas/Fort Worth, Texas
• Houston, Texas

To learn more, visit our program page and request information to get in touch with one of our Admissions Representatives today.