Tip maintenance of your soldering iron is a necessary action. Without proper tip care your soldering days are greatly reduced and tip replacement comes sooner than expected. With high heat needed for soldering, especially for lead-free soldering, tip burnout is more likely to occur. Temperatures of 700 – 750 degrees Fahrenheit for lead-free and 650 – 700 degrees Fahrenheit for tin/lead are not uncommon. Some soldering stations are capable of reaching 900 degrees Fahrenheit.
As you can see lead-free solder requires a much higher heat to melt. Sometimes this leads to “cold tips” where the ends turn black and the solder fails to adhere to the tip surface. You may think the tips are not heating properly when the solder just balls up and falls off the ends. But, don’t be fooled, this stuff is still hot and can burn you. Shown below is an example of how some manufacturers have overcome the overheating problem. This technology is built into the soldering tips that I prefer to use for my own jobs.
Smartheat Soldering Tips
With tips generally made with a soft copper core the outside is coated with some form of metal alloy such as iron. Iron can withstand an immense amount of heat over a long period of time. However, if the iron or other surface coating is damaged, such as scratching or bending, the tip will incur heat loss and the “cold tip” syndrome will commence. Iron can also corrode causing dewetting.
In order to prevent premature tip failure a few things can be done to negate this. Turn the heat down! When not using the soldering station for five to ten minutes turn it off. This will help in maintaining a longer tip life. Most modern soldering stations can heat up and cool down within just a few seconds. So, why not utilize this feature and save your tips from an early grave? Heat wears out tips.
Next, make sure the tip is clean and tinned prior to placing it back in the holder. Tips will wear out much quicker when not properly cleaned and tinned. Lastly, use the proper cleaning tools for tip maintenance. A battery terminal scraper is not the correct tool for cleaning soldering tips.
Another useful thing to remember is to keep your solder types separate. Lead-free solder should never be used with a tip that is used for tin/lead RMA or non-rosin core solder. When you mix solder types the layer of solder left on the tip from tinning will have a lasting affect every time you use the tip.
Example of the proper way to maintain soldering tips
Now, it’s not to say that you can’t use the same tip for each type of solder. However, the extreme cleaning action needed to completely remove the tin/lead or lead free solder from the tip is harder to accomplish than just switching tips. “Why not just keep tips separate for lead-free and tin/lead? This would negate any problems down the line if you perform both types of soldering on a continuous basis.
Let’s take a look at maintaining a tip utilizing tin/lead solder. Since tin/lead soldering is the most widely used method in electronics manufacturing I will cover that first.
Before you start soldering, the tip of your iron should be cleaned of any residual solder, flux, or debris. Start by heating up the tip to its normal operating temperature that you have set. Next, clean the tip on a sponge and then with some soft brass wool or “brass brillo” as we call it in the industry. Ensure you use a cellulose sponge and not a synthetic sponge. The synthetic types will melt when the tip comes in contact. In addition, remember to use only deionized water. Regular tap water has minerals that will shorten and damage the life of your tip.
Example of Brass Wool or "Brillo"
Make sure all solder has been removed. Next, melt just a dab on the tip to prevent oxidation. A dirty tip with no tinning will not conduct heat properly from the tip to the part to be soldered. You can also use a burnishing tool if you don’t have access to a rotary cleaner or a can of tip tinner. I don’t recommend using a burnishing or polishing tool unless you don’t have any other method of cleaning your tips. Tip tinner works well for tips in removing burnt on flux and debris. Just roll the heated tip around inside the tinning can until the black color turns to silver and you know then that it is clean. Once cleaned, remove the excess tip tinner with the sponge and brass brillo. Then re-apply solder to tin the tip properly. Tip tinner is not meant to be left on the tip. It is only for cleaning the tips and nothing else.
Example of Tip Tinner
If you have cleaned the tip properly, and the solder has adhered to the tip while pre-tinning, then you have successfully cleaned the tip. If the tip is not cleaned properly and the solder just balls up as you try to tin the tip, then more than likely it is still dirty or damaged.
Never and I mean never, bend or dent the tips to another shape. Never pull a tip out or install with a pair of pliers. Soldering tips are meant to apply solder and not to be bent to a different shape. If you need a 90 degree tip and only have a straight tip then spend the money and get the right tip. When you bend a tip or damage it by yanking on it with pliers the tip becomes ineffective in completing the soldering job efficiently. Heat transfer is lost due to the damage incurred.
In some instances the sponge and brass wool become ineffective in cleaning your tips. There are rotary motor driven tip cleaners that can remove more oxidation than normal cleaning can provide. These units are a little more expensive than hand cleaning methods. However, if you are a serious solder technician they are worth the cost. I personally use one in my own lab on a monthly basis and they save time and money replacing expensive tips.
Example of a soldering tip polishing tool
When using lead-free solder, cleaning and maintaining the tips are pretty much the same as with tin/lead tips. However, temperature ratings are much higher for lead-free tip usage and therefore the tips tend to wear out much sooner.
So, when you decide to perform maintenance on your own tips remember to treat them gently. A well maintained set of tips should last for a very long time. I have tips that are over five years old and still perform as if they were bought just yesterday.