To join materials together, particularly metals, you need intense heat so that the metals can melt and then bond together. That said, each metal has its own characteristics, so no one metal-joining method is going to work effectively on all metals.
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Luckily, there are three common techniques used to join metals, but if you don’t know the differences between them, it may be difficult to choose the best one for your project.
So, what’s the difference between soldering, welding, and brazing? The main difference between these techniques is the temperature used to melt the metal. Welding is the most intense, while in soldering, the metal barely softens.
Because each method has its benefits and drawbacks, keep reading to know all the differences between soldering, welding, and brazing.
The Key Differences Between Soldering vs Welding, and Brazing
Soldering, welding, and brazing are different techniques suitable for different materials and applications. The key distinction between each technique is the temperature used.
As a result, each method produces a different type of joint that has its pros and cons. To understand which one is best for your project, you first need to know the main differences between them.
Soldering
In soldering, metals are joined together using a metal solder filler. This solder is typically an alloy of lead and tin, which has a low melting point.
The solder is melted by heating it to about 600 °F. When it cools down, it creates a joint between the two metal pieces, both of which have barely softened.
Soldering is typically used in the electronics industry, usually to join copper to circuit boards. It can also be used to join plumbing pipes. However, the most common use of soldering is in
jewelry making because it doesn’t have much effect on the actual metal.
It’s a fairly easy method. All you need is the solder metal and a soldering iron or a soldering gun. The best part is that it’s also a reversible process. Any joining you’ve made can easily be desoldered.
Advantages:
-The original workpiece metal isn’t distorted or harmed
-Lower temperature than other methods
-Can join different metals
-Can safely join thin materials
-Doesn’t require heat treatment
-The easiest at-home method
Disadvantages:
-Creates relatively weak joints
-Can’t fuse larger pieces of metal
-Solder material usually contains toxic lead
Welding
The main purpose of welding is to join together parts, usually metal, using intense heat. The temperature is high enough to melt the original metal creating a joint when it cools back.
So, as opposed to soldering, welding does melt the original workpiece, which requires a high temperature of about 6500 °F.
The formed joint is called a weld. It’s incredibly strong since it’s formed under intense heat and pressure, sometimes even stronger than the parent material.
Welding can be used for materials other than metals. It’s all about adjusting the temperature. You can weld plastics and even wood.
However, not all materials can be welded. These are called unweldable materials and won’t stick together no matter what method you use.
There are numerous types of welding depending on the process and heat source used. They include electron beam welding, arc welding, and laser welding.
Welding produces the strongest joints. That’s why it’s used in most big structures you see in everyday life, including planes, bridges, and cars.
Advantages:
-Produces the strongest joints
-Can fuse many materials, including plastic and wood
-Can join large sections of metal
Disadvantages
-High temperature may damage the original workpiece
-Requires post-process heat treatment
-Can be unsafe
Brazing
Brazing may actually be considered a high-temperature type of soldering. As with soldering, a molten metal alloy forms the joint between the two original workpieces. It is often used by plumbers to connect copper pipes. More modern techniques don’t require brazing as there are copper fittings that can be pushed together.
The filler metal is usually heated above 840 °F. This temperature is traditionally above the filler metal’s melting point, but still not high enough to soften the workpiece metal.
There are multiple heat sources to use in brazing:
Localized heating using a torch
High-frequency induction or high resistance electric current
Diffuse heating using furnace brazing or dip brazing
Due to the high temperature at which the filler metal is heated, the filler needs to be protected with a flux.
Since brazing requires less heat than welding but produces stronger joints than soldering, it’s a reliable joining method for most materials, including electrical components and pipes.
Advantages
-Less chance of damaging the original parts
-Stronger joints than soldering
-Can fuse dissimilar metals
-Doesn’t require post-heat processing
Disadvantages
-Produces joints weaker than welding
-Fluxes may have toxic components
-The produced joints have a different noticeable color
-When to Choose Soldering, Welding, and Brazing
Should you use Soldering, Welding or Brazing?
Now that you know all of the differences, as well as the advantages and disadvantages of each method, which of the three techniques would be most suitable for certain projects?
There are certain factors regarding your workpiece and your equipment to consider.
Type of Metals
Welding can melt the original workpiece, so it requires a hard metal that isn’t easily denatured.
Not only that, but if you’re working with two different metals, such as copper and steel, they simply won’t fuse by welding. This is because each metal has unique properties, including a different melting point.
If you need to melt different metals, brazing or soldering is the better option. Both don’t even require melting the original material. These techniques, however, only fuse together small, thin sections.
Strength of Joint
Soldering uses lower heat than brazing, which makes it less abrasive but creates weaker bonds. So, it’s best for jewelry making or electrical boards.
Alternatively, welding fuses metals by melting the original workpiece, creating the strongest joints. That’s why welding is best for heavy-duty projects.
Cost of Process
Other factors to consider are time and cost. Welding is the most time and cost-consuming because it requires a lot of safety precautions, metal preparation, and post-heat processing.
Soldering can simply be done using a soldering gun and is, by far, the easiest, most cost-friendly of the three techniques.
While brazing requires more heavy-duty supplies than soldering, it’s still a low-maintenance option compared to welding.
Conclusion
The main difference between soldering, welding, and brazing is the temperature applied to the metal.
The highest temperature is used in welding, which requires melting the original metal so it resolidifies into a joint. On the other hand, brazing only melts the filler material and partially heats the original metal. Lastly, soldering barely heats the original metal.
Each technique is suitable for different applications. For instance, welding is the best way to join large, thick pieces of metal, but they must be similar so they fuse correctly. Brazing and soldering, on the other hand, use a filler material that’s best for thin small joints.
Even if you’re not regularly soldering, welding, or brazing metals, now you know which method to choose for your next DIY project!
