Solder Paste

Solder paste is a form of solder commonly used for printed circuit board (PCB) assembly, both in mass production and for prototyping. A mix of small solder spheres and solder flux, this paste comes in a variety of forms and must be carefully applied for consistent and reliable results.

You'll find a range of soldering paste for electronics available through our website including different manufacturers, grades, alloys and types of flux. Whether you're looking for AIM M8 solder paste, MG Chemicals solder paste or another popular product, we're likely to have it in stock and ready to ship.

Browse our product selection online to find the ideal paste for your application. You can also read more about how solder paste works and the different types available below.

What is solder paste?

Solder paste is a mixture of small solder spheres within solder flux that's used to connect surface mount components, such as resistors and capacitors, to PCB pads. A high-quality solder paste that's carefully applied provides a strong mechanical bond and electrical connection, assuring board performance and component longevity.

You can buy solder paste in bottles, tubs or syringes, depending on the volume needed for your application.

How does solder paste work?

Solder paste provides a convenient method of solder application. Initially, the paste holds components in place before the board and its components are heated. The user then applies heat to melt the paste, create a connection and bond the various parts together. This process is called reflow.

What are the different types of soldering paste for electronics?

The solder spheres in solder paste are an alloy of metals, traditionally tin and lead. The lead found in popular products such as 60/40 solder paste is ideal for soldering as it has a low melting point and readily flows. But health concerns and modern legislation around the use of lead have given rise to several lead-free solder paste products, using metals such as silver and copper.

There are also several grades of solder paste according to the size of the solder spheres. The right grade for your application will depend on the size of your connectors and contacts, as overly large particles can become difficult to work with on smaller boards.

Soldering paste for electronics also contains different flux types:

• Rosin-based solder paste contains rosin and is highly efficient
• Water-soluble solder paste is highly active but needs to be cleaned off to prevent corrosion
• No-clean solder paste doesn't demand the use of cleaning agents after application

How to use solder paste

Whether using solder paste for mass production, prototyping or reworking, the soldering process follows a few basic steps:

• First, apply solder paste to the PCB in the areas where solder is needed. This can be done with a solder paste stencil, which only allows a certain amount of paste through.
• Once the paste is applied, the components can be added either manually or using a pick and place machine.
• The solder paste will hold the applied components in place. You should avoid knocking the board or leaving it too long to solder, otherwise components may become displaced or the solder paste may deteriorate.

It's important to carefully control the soldering process to prevent defects in PCB assembly. Make sure to apply appropriate amounts in the correct places, using a solder paste that is in good condition.

How to store solder paste

All solder paste deteriorates over time. It's important to store it correctly to maintain its critical properties, minimize deterioration and guarantee high performance within its shelf life. Here are three key storage tips:

• Store solder paste in an airtight container to prevent oxidation. This is a significant risk due to the large surface area of the solder spheres.
• Store it at low temperatures - but not below freezing - to reduce the rate of any oxidation, and slow down degradation of the flux.
• Avoid using solder paste after its end date. Using old solder paste brings a higher risk of defects which will require repair and replacement.

Order quality solder paste with RS

If you need a solder paste you can rely on for easy application and long-lasting results, you'll find the solution in our product range. As one of North America's largest tool and hardware distributors, we have the stock, manufacturer network and shipping capabilities to help you get to work.

Browse our product selection online and apply search filters to quickly find the ideal solder paste for your needs. If you have any questions about our products or our service, don't hesitate to contact our team.

You can also visit our expert hub for product advice and industry news.