What Is Soldering Paste? (ANSWERED!)

In a lot of movies, there’s always this intense scene featuring a techie soldering a piece of metal on a motherboard. We’re sure you’ve come across such a scene before.

Soldering isn’t limited to electrical applications, though. It’s now being used in a variety of fields, from plumbing to jewelry making.

You’ve come to the right place if you’re new to soldering and need help understanding how you can use it. We’ll answer all your burning questions, from how soldering works to what soldering paste is.


Let’s get started!

What Does Soldering Mean?

Simply, soldering is the process of fusing a metal alloy (solder) with one or more metal parts. The connection between the two metals can be electrical, mechanical, or both. This makes it very popular in a wide range of industries.

Soldering is viewed as a basic skill in the electronics industry, seeing as it helps form electrical connections, especially when it comes to fixing joints/tips on a printed circuit board (PCB).

It’s also a common method used by plumbers to join copper pipes. What’s more, jewelers can use it to join the ends of an accessory or even repair one.

It’s easy to desolder a fusion if you want. By using proper techniques, you can easily separate the metal parts. This allows for more trial and error in some fields as well as a range of options for customizations in other fields.

What Are the Basic Soldering Components?

Before getting into the process, we’ll go over the main components of soldering so you have a better understanding of their roles:


The solder is a low-melting alloy that’s either tin-lead or lead-free. Tin-lead solders were popular back in the day. However, their use has been limited since the lead ban went into effect in 1986. You see, lead causes serious health problems and has a negative impact on the environment.

Following that, lead-free solders were manufactured using other metals such as silver, copper, brass, tin, nickel, or bismuth. On a side note, the application of solders is determined by the metal ratio in the alloy.

Solder is the fusible alloy that we melt to adhere to metal pieces. Then, as it cools, it forms a strong bond. Bonds can have electrical properties that aid in the completion of an electric circuit. They can also have mechanical characteristics only that are mainly used for adhesion purposes.

Interestingly, the word “solder” is derived from the Latin word “solidare.” This word means to combine two things into one and create something stronger or more solid.


Flux is a liquid injected into the core of a solder wire. Rosin (type R) flux is the type of flux used in solders. It acts as a surface cleaner during soldering, removing any small particles that could cause an imperfect joint. It also keeps molten solder from oxidizing.

A word of caution: the fumes produced by soldering are caused by the flux burning away. These fumes are extremely dangerous. So always work in a well-ventilated area and follow all safety precautions.

Soldering Iron

We like to think of this tool as a middleman. A soldering iron is a hand tool used to heat solder, which in return facilitates the connection of two metals.

The soldering iron has an insulated handle and a metal tip that transfers heat. It resembles and feels like holding an enlarged pen.

This tool is available in a variety of shapes and sizes, but most of them are powered by electricity. Besides, it usually comes with temperature controllers, giving you more control over the temperature you want to obtain.

How Does the Soldering Process Work?

You might presume that, because soldering is used in several industries, it must be complicated. That’s not the case. It’s a simple process that can be mastered with a “practice makes perfect” mindset.

After knowing the functions of each component, all we have to do now for the process is connect the dots:

-Heat the iron above the solder melting point, which is approximately 600 to 700°F.

-Clean the iron’s tip with a wet sponge or brass sponge to remove any oxidation.

-Place the solder on one end of the metal piece and the iron on the other.

-When finished, remove the solder before the iron.

-Allow the fused section to cool for a few seconds.

What Is Soldering Paste?

Soldering paste, also known as solder paste flux, functions as an adhesive in the same way that solder wire does.

It’s mostly used in PCBs to secure mount devices to the board’s surface and pads while also establishing an electrical and mechanical connection.

Naturally, because it’s a paste, its composition and process differ. Solder paste consists of two main components: solder particles in the form of powder and flux.

In terms of weight, a typical solder paste contains 90% solder particles and 10% flux, whereas, in terms of volume, the ratio is 45% solder and 55% flux.

Solder Powder

The powder is made up of tiny spherical metallic particles of varying sizes. Their size is measured in microns on a scale that gets smaller as you move up the ranks.

Solder powder also contains chemicals, such as activators, and alloy compositions in varying ratios.

To sum up, there are several types of solder pastes that are used for different applications. The key distinction between each type is the size of the metallic particles as well as the different percentages of chemicals and metals.


Flux cleans the surface of dust, debris, and oxidation to ensure perfect bonding. It also acts as a temporary adhesive. Its gel-like consistency aids in keeping metal parts intact while you work on fusing them.

In Short

For us, soldering is the perfect example of “easy does it.” As you can see, the process doesn’t call for much. However, for it to work, you need to be focused and organized.

Finally, we hope that by now you’ve learned the answers to “What does soldering mean?” and “What is soldering paste?” by heart.

We have discussed what soldering is made out of here.