Short answer
Soldering and brazing form joints using melted filler rather than melted components; the AWS handbook separates them at 840°F (450°C), with brazing above and soldering below. Welding, in the handbook’s melting-based comparison, also melts the base metal. That welding description should not be treated as a complete account of every welding process. 2
On this page
At a glance
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| Question | Soldering | Brazing | Welding |
|---|---|---|---|
| What melts? | Filler, in this comparison | Filler, not components | Base metal and filler in the described comparison |
| Temperature distinction? | Below 840°F (450°C) | Filler liquidus above 840°F (450°C) | Not defined by this boundary |
| Joint-forming emphasis? | Lower-temperature filler joining | Filler between closely fitted surfaces | Base-metal coalescence through melting |
These entries follow the handbook’s comparison, rather than a complete welding taxonomy. 2
What each thing is
The base materials are the components being joined; filler metal is the joining material introduced between them. Brazing is explicitly a family of processes. Soldering is its lower-temperature counterpart in this comparison, while welding is contrasted by melting the base materials themselves. 2
Key differences
There are two separate distinctions, not one temperature ladder. First ask whether the components melt. Then, for soldering versus brazing, consider the filler-temperature classification. The formal brazing definition specifies filler liquidus above the boundary but below the base materials’ solidus—not merely that the equipment becomes hot. 2
How to tell them apart
Look for a process description stating what melts. Filler-only joining points toward soldering or brazing; the filler temperature separates those two. Base-metal melting describes fusion welding, but other welding processes need more specific treatment. Appearance alone cannot classify an undocumented joint. 2
Where they overlap
The application does not uniquely identify the process. AWS lists soldering in electronics, but also in piping, gutters, kitchen equipment, and hand tools. It also lists industries using both brazing and soldering. Thus, an electrical versus mechanical use is not the defining boundary. 1
Edge cases
The exact 840°F (450°C) boundary needs the applicable standard’s wording: the handbook passage says above for brazing and below for soldering without assigning equality. Another name, braze welding, appears alongside brazing in an AWS filler-metal specification; the name alone should not be used to assume that the base metal melts. 2 1
Why the distinction exists
The terminology distinguishes the material participating in melting and, for filler-based joining, the temperature category. That makes the names more informative than a generic label such as metal joining. AWS describes its terminology glossary as a means of improving communication about welding and allied processes. 2 1
Common misconceptions
Soldering does not mean electronics only, and brazing does not mean melting the parts together. Nor does the heating-method name settle the category: AWS lists both torch and furnace soldering, as well as resistance brazing. Process identity depends on more than the heat-source label. 1 2
Examples
Two hypothetical cases apply the distinction. First, a connector joint uses filler classified below 840°F (450°C), without component melting: that fits soldering, consistent with AWS’s connector examples. Second, closely fitted metal parts remain unmelted while filler with a liquidus above that boundary joins them: that fits brazing, not the welding comparison described here. 1 2