Differences in Brazing vs. Soldering vs. Welding

Brazing, soldering, and welding are techniques for joining two or more metal pieces. Although several differences exist among these processes, the primary distinction is the temperature required to create the joint.
In most cases, welding entails melting the base metals to create a fused joint. It may or may not require filler metals or shielding gases.
Brazing and soldering, on the other hand, are alike in that they melt the filler metal but not the base metals. The heated filler metal is applied to the base materials, and when it cools and solidifies, it creates a joint. The hotter melting temperature of the filler metal during brazing differentiates the two processes.

Here is a detailed look at the difference between brazing, soldering, and welding:

What are the common features that compare brazing, soldering, and welding?

Joining metal requires soldering, brazing, and welding. And while each of these methods is different, they also have a few things in common.

• Cleaning the metal pieces: Whichever process you choose, you will not be completely successful unless you start with clean material.
• Heating the material: All three methods require adequate heat to create a strong joint.
• Proper safety equipment: Using eye protection, safety gloves, protective clothes, and helmets is an essential part of each of these methods.

What is brazing?

The brazing process combines heat, filler material, and flux to join two or more metals. A flux solution between the filler metal and base metal helps to join them during heating. The melting point of the filler metal is above 850°F, but it is always lower than the melting temperature of the metals being joined. The molten filler metal cools, providing a strong join between the same or different types of metals.

Brazing works well for thin metals such as aluminum, where higher temperatures can damage them. Because of its flexibility and the high integrity to which joints can be created, brazing is used in a wide variety of industries. It is reliable in various applications, making it one of the most popular joining methods.

The Pros and Cons of Brazing

Pros	Cons
Base metal does not melt	Larger sections cannot be joined
Neat joints without cleaning	Joint not as strong as with welding
Can join dissimilar metals	Possible toxic elements in the filler material
Economical way to fuse materials	High temperature can damage the joint
Simple technique	Joint color differs from base metal

 

What is soldering?

Solder is the filler metal melted at a relatively low temperature (under 800°F) using a soldering iron. The soldering process joins metal parts to form a mechanical or electrical bond. The solder bonds to the metal parts, creating a connection after the solder solidifies.

Even though soldering is used for plumbing, sheet metal fabrication, and automotive radiator repair, the most common application of soldering is assembling electrical components and wiring electrical contacts. As with brazing, the joined parts are not melted and are often a different material than the solder.

The Pros and Cons of Soldering

Pros	Cons
No need to melt the base metal	Cannot fuse larger sections
Low-temperature process	Low-strength joints
Thin-walled parts can be joined	Unfit for high-temperature applications
Low-cost method	It may contain toxic components
Easy to learn

 

What is welding?

Unlike in brazing and soldering, a high temperature is used in welding to heat the filler material and the edges of the base metal, establishing a strong bond between the metals. Temperatures over 850°F create a weld pool of molten metal that cools to form a much stronger joint than either brazing or soldering. Shielding gas is sometimes used in the welding process to protect the melted and filler metals from becoming contaminated or oxidized.

Welding is employed in various industries, including construction, automotive, aircraft, pipelines, tanks, vessels, bridges, and railroads. And there are several welding methods from which to choose: MIG, TIG, stick, laser, gas, and underwater welding are just some of the most common.

The Pros and Cons of Welding

Pros	Cons
Works on a variety of materials	Some danger from heat, light, and radiation
Strong and secure joints	Can be expensive
It can be done almost anywhere	Typically not suitable for thin metals
Large sections are easily joined	Base metal contortion
Relatively economical procedure

 

Side-by-side comparison showing the difference between brazing, soldering, and welding

Brazing	Soldering	Welding
Joints are stronger than soldering but weaker than welding. It can be used to bear some load.	It produces the weakest joint of the three. Typically used for electrical contacts, it cannot bear much weight.	Strongest joints capable of bearing loads. The strength of a welded joint often exceeds the strength of the base metal.
Temperatures can be as much as 1,000°F	Temperatures around 800°F	Temperatures of up to 7,000°F possible
The workpiece is heated below its melting point	No heating required on the workpiece	The workpiece is heated to the melting point
The mechanical properties of the joint may show a negligible change	No change in mechanical properties after joining.	The mechanical properties of the base metal may change in the joint because of heating and cooling.
The costs involved and the skills needed are in between the two other methods	The costs involved and the skill requirement is very low.	It can require high costs and high-level skills.
No heat treatment	No heat treatment	Often requires heat treatment to eliminate the unwanted effects of welding.
Because brazing is done at low temperatures, preheating can help to form a solid joint	Preheating the workpiece before soldering is also good for making quality joints.	Since it is performed at a high temperature, preheating the work is not necessary for welding.