This article is based on an original publication by Chris Stuber, Product Manager for American Hakko Products, Inc.
As the old adage goes, nothing lasts forever. This is especially true when it comes to machines and other products that are tasked with performing labor-intensive actions under stressful conditions. Soldering irons are no exception. They are designed to work with chemicals under high heat. Over time, soldering tips degrade through a series of physical changes that affect their performance. Once a tip no longer delivers quality solder connections, it is ready for retirement. With this in mind, how does one make the most out of the limited time a soldering tip is able to deliver optimal results? The answer lies with understanding the changes solder tips undergo during use.
Soldering Tip Construction
A soldering tip’s construction is the first necessary component in understanding these changes. The copper plated core “conducts heat energy from the heating element to the application being soldered.” An iron plating protects the copper from corrosion due to exposure to various soldering materials while chromium plating protects the iron plating (excluding the tip) from corrosion.
Tip Maintenance
Just as regular oil changes and tune-ups will extend the life of vehicles, soldering tips that receive regular maintenance tend to perform better over a longer period. Aside from treating your soldering equipment with care, there are other steps you can take to ensure long life for your soldering tips. Frequently cleaning the tip with a damp sponge (using only distilled water or de-ionized water) or non abrasive tip cleaner removes oxidized solder, flux residue and debris.
Be cautious when using chemical tip cleaners, as they have aggressive cleaning properties similar to highly active fluxes. They also may cause residue build-up that blackens the tip and oxidizes the plating. Gentle chemical tip cleaners can be used sparingly but as mentioned before, distilled water or deionized water is preferable.
Finally, applying solder to the tip’s working surface provides additional protection (known as “tinning the tip”) by covering the work surface and preventing it from reacting with the surrounding air, keeping oxidation and corrosion at bay.
Tip Temperature
Temperature plays a large role in solder tip degradation in several ways, the most obvious being physical changes due to thermal expansion while heating and contraction while cooling. This expansion and contraction weakens the tip’s structure over time. High temperatures also accelerate chemical reactions between the plating and the solder (particularly tin solder), both on the tip and in the air surrounding the tip, and they speed up tip oxidation and solder and flux reaction with the tip’s iron plating.
Solder
The type of solder used also affects the performance life of soldering tips. Solders high in tin (Sn) and other chemicals shorter tip life by degrading the tip via chemical reactions over time. Therefore, understanding how different solders affect solder tips is important.
Flux
Fluxes with more aggressive cleaning action inflict more degradation faster upon the solder tip.
Conversely, mildly active fluxes do not wear plating on the tip as fast.
Operator Technique
How you handle and use the solder tip has a big influence on its life expectancy. Some techniques tend to cause more physical abrasion and other types of damage to the tip. Selecting the proper tip for a given application can improve handling, performance and heat distribution, thus extending the tip’s performance life.
Soldering/Rework Application
Finally, the application itself has an effect on the tip’s life. An intense application requiring certain types of solder and high heat tend to accelerate deterioration. While it’s not always possible to choose which solder applications you work on, understanding an application’s effect on solder tips can be a useful tool in deciding which to use.
Understanding how various procedures and elements inherent in the soldering process can enable you to effectively extend the life of your solder tips. Nothing will prevent degradation but there are many ways to stave damage in order to get more life from your solder tips and your other solder tools.