Home - Blog

What Metal is Solder: Variants You Can Apply

Soldering has been an integral part of electronics since the 19th century. It’s the go-to for creating conductive links between metal items. Plus, it offers sought-after reversibility needed in most circuits and metal works. But what metal is solder?

While you can’t solder some metals, quite a few provide excellent solderability. For this reason, we can’t answer the question without exploring all the possible options. 

Thankfully, this article will detail the metals you can use as solder and discuss the most common ones.

Are you ready? Let’s go!

Let’s Start with the Basics

Before we dive into the list of solderable metals, let’s kick off with the basic information for beginners. What is soldering? It’s a process that uses solder to link other metal pieces. Solder works like glue but for mechanical and electrical connections.

Interestingly, the soldering process is simple. It starts by heating the solder to its melting point before joining metals or wires with a soldering iron. Then, the melted solder will solidify after it cools down to create a durable metal bond. In addition, you can easily reverse the process with desoldering.

What Metals can Serve as Solders?

Soldering iron and solder

Soldering iron and solder

As mentioned earlier, you have various options when selecting a solder. But you may need little research on the metals required for your application.

One of the most popular options available is Brass. This metal offers a reliable, easy, and simple solder for various applications. And hobbyists can use them consistently for DIY applications.

In addition, Lead-based filler metals were also popular at some point. However, they’re no longer applicable today due to their harmful effects on human health and the environment. Regardless, lead-based solders are easy to apply and preferred for intensive applications.

You can access more lead-free solders like tin, copper, indium, silver, and antimony. Further, some metals can create durable chemical or physical bonds independently, while others (like aluminum) need backup from alloys with higher melting points.

Soldering iron with a roll of solder

Soldering iron with a roll of solder

Also, we can classify lead or tin as soft solders due to their low melting points. And these metals are tricky to process with other metals that oxidize quickly. In contrast, variants with high melting points fall under the “hard solder” category.

What’s more? You can access other soldiers called ‘wiping soldiers.’ In truth, these variants have impressive compositions, making them fluid and easy to manipulate. For example, cable-wiping solder possesses extreme tin content but provides a strong bond.

Gold, silver, and copper are easy to solder, while nickel, iron, and mild steel are tricky. Lastly, aluminum and stainless steel are even more difficult.

What are the Most Common Metals used for Soldering?

Hands soldering a PCB

Hands soldering a PCB

Lead and tin are the two most used metals for Soldering. Lead is the most common and widely used due to its high success rates. Also, most manufacturers maintain a 60:40 ratio (when micing lead and tin) to achieve a 180 to 190 °C melting point. And higher in concentrations generate better shear and tensile strength.

However, the EU banned lead-based soldering options due to their hazardous effects. Thankfully, many lead-free alternatives are ready to take the spot. For example, silver solders are excellent replacements for lead-based options.

Note: Keep in mind that lead-free doesn’t always translate to safe. Other metals can also generate less or more toxic fumes.

Understanding Solder Blends

Soldering process

Soldering process

Soldiers often comprise different blends to achieve specific compositions. In truth, different metal mixing ratios result in different solder types.  Also, the additive percentage makes each solder type different.

For instance, antimony is a popular alloy used by soldiers. Manufacturers add this metal to increase mechanical strength and deter pests. However, it doesn’t reduce wettability.

Further, adding indium, copper, and bismuth reduces the solder’s melting point while enhancing wetting properties. Also, indium improves flexibility, especially when added to gold solder, and they’re expensive.

Also, we can use silver to achieve mechanical strength, but at the cost of flexibility. More importantly, you can use specific metal ratio combinations for special applications to create strong joints.

What Metals are not solderable?

Not all metals make the soldering process easy. Metals like titanium are often too reactive to work with substances like brazing flux.

Other hard-to-solder metals include steel, chromium, and other nickel-based metal alloys. Why? Because they have melting points higher than what we require for solder.

Final Words

Today, you can access various mixture ratios and types of solders for your applications. Lead-based and lead-free variants are some of the most popular options available. Despite the obvious dangers of lead-based soldiers, most professionals prefer using them for projects.

Thankfully, you can use lead-free techniques for electronic devices that meet health and environmental requirements. Also, not all metals are solderable due to unwanted reactions or extreme melting points.

Do you have more questions? Please, leave a message, and we’ll be glad to help.

Avatar photo
Emma Lu
Our professional engineering support saves our customers a lot of trouble and loss. >>>>>> After you place the order, our engineer will conduct technical reviews to make sure the parts can be mounted well/correctly on the boards. We will check if the component packages match well with the Gerber footprints, if the part numbers you provided match well with the descriptions, and if the polarity is clearly marked. >>>>> When your design is ready, please send your Gerber and BOM so we can quote and start!