In this article we are going to take a look at a few soldering tips and how to deal with oxidation.
A soldering iron can be an indispensable tool for electronics use. A new or adequately cared for soldering iron is very efficient in its operation, allowing components to be quickly and easily soldered into place. But sometimes the soldering tip gets a buildup of oxidation on its surface. When this happens, the soldering iron no longer functions as it should. But with a little effort, the tool can be restored to complete functionality. Let’s take a look at soldering tips and how to deal with oxidation.
The Soldering Tip
In the past (and in some very cheap tools today), soldering tips were constructed of copper. The tips were shaped by filing or sanding, and there was no plating involved. The copper from the tip eventually dissolved into the solder, leaving a pitted and eroded surface. This directly affected soldering performance.
Starting in the 1980s, iron plating was added to the thermally efficient copper tip. This prevented the copper from dissolving into the solder, giving the tip a much longer (and predictable) operational life.
While the iron plating on a tip is excellent for extending the life, it can lead to oxidation issues.
What Causes Oxidation in Solder Tips?
Solder tip oxidation is created when the iron plating on the tip becomes iron oxide and is a natural part of the metals used. Oxidation will occur at room temperature, but at a much slower rate. The heat of soldering dramatically accelerates this process.
The biggest factor affecting tip performance in oxidation will be the loss of wetting ability. As oxidation builds up on the tip, it creates a thermal dewetting barrier. When this happens, the solder will tend to ball up on the tip instead of flowing smoothly.
The oxidized layer will also impact heat transfer between the tip and the work. Many times a soldering iron that does not seem to be hot enough is actually suffering from oxidation.
Removing Mild Oxidation
Any soldering tip will have a small amount of oxidation, it’s part of the natural process of the iron plating. But any kind of buildup will impact soldering performance. If you are experiencing reduced effectiveness from a soldering iron, or there is visible oxidation, you should clean the tip to restore proper operation.
- Adjust the temperature of the soldering iron to a typical work range (about 300°C).
- Apply flux-cored solder to the oxidized tip. The heat will activate the flux and start the chemical reaction that will remove the oxidation.
- Use brass wool or specially designed cleaners on the tip. The cleaning tool will begin to remove the oxidation.
- Repeat the steps above until the tip is clean. The tip should show allow for smooth solder flow when it is clean. For a mild case of oxidation, expect to repeat this process three or four times.
If this process does not adequately clean the tip, or if the tip is severely oxidized, you may need to follow the instructions for severe oxidation.
You may notice some black residue from the flux, especially on the tip. It is not necessary to remove this residue, as it will not adversely affect soldering operation. In fact, you could damage tip integrity in the process, so consider leaving this.
Damaged Tip Signs
If the iron plating on a soldering tip is damaged, it can lead to problems with the soldering performance. A crack or hole in the plating will allow the copper interior of the tip to come into contact with the solder. When this happens, the copper will dissolve into the solder, impacting the tip’s integrity.
In some cases, the copper will dissolve enough to leave a hole in the tip, leaving the rest of the iron plating intact. Inspect the tip for this kind of damage, and if it is found the tip or cartridge should be removed from use and replaced.
Once you have checked your solder tip for damage and cleaned it, it might be a good idea to avoid excessive oxidation by following our helpful tips.
Tips to Prevent Oxidation
There are several ways to reduce oxidation buildup on solder tips.
Use a protective layer of solder – The easiest way to prevent oxidation of a solder tip is to protect it with a layer of solder. Each time you clean the soldering iron and put it away, apply a fresh solder to the tip. The best solder for oxidation prevention is one with a high amount of flux core.
Keep the tip clean – Keeping a tip clean is also a solid strategy to reduce oxidation. You will find that both a damp sponge and a wire cleaner will be effective for cleaning a tip. Some solder will respond to one method better over the other.
When cleaning a solder tip with a damp sponge, be sure to let the iron return to its set temperature before wiping again. This will maximize the cleaning the sponge offers by keeping the tip material in a flowing state.
Avoid unnecessary heat – Excessive heat can also contribute to oxidation buildup on a solder tip. Make sure that you use the proper temperature for the selected solder type and application. Keeping a soldering iron at a higher than needed temperature can damage the work product as well as shorten the life of the tip.
Lead-free solder will typically require a higher temperature than one containing lead, so be sure to check the temperature when moving between solder types.
Today there are advanced soldering systems on the market today that use microprocessor control to precisely regulate the tip temperature. These systems use a sensor on the tip to control power flow. The end result is that the tip stays a constant temperature, extending life and protecting work.
Turn it off when not in use – If you know that you won’t be doing any soldering for a period of time, go ahead and turn the iron off. The natural oxidation process happens at a much slower rate at room temperature. Keeping the iron off when not in use is safer too.
There are advanced soldering irons that incorporate an auto sleep feature into their design. These tools will automatically power down the tip when not in use, extending tip life.
With the right practices, a solder tip can provide a long service life before oxidation becomes a problem. And once it does become an issue, a proper cleaning with the right products can keep a soldering tool working for a long time. We carry a variety of soldering, desoldering, and reworking tools, featuring SmartHeat® Technology. Contact us today to see how we can make your hand soldering efforts a success.