Soldering Iron - Cleaning

Cleaning

When the iron tip oxidises and burnt flux accumulates on it, solder no longer wets the tip, impeding heat transfer and making soldering difficult or impossible; tips must be periodically cleaned in use. Such problems happen with all kinds of solder, but are much more severe with the lead-free solders which have become widespread in electronics work, which require higher temperatures than solders containing lead. Exposed iron plating oxidises; if the tip is kept tinned with molten solder oxidation is inhibited. A clean unoxidised tip is tinned by applying a little solder and flux.

A wetted small sponge, often supplied with soldering equipment, can be used to wipe the tip. For lead-free solder a slightly more aggressive cleaning, with brass shavings, can be used. Soldering flux will help to remove oxide; the more active the flux the better the cleaning, although acidic flux used on circuit boards and not carefully cleaned off will cause corrosion. A tip which is cleaned but not retinned is susceptible to oxidation, particularly if wet.

Soldering iron tips are made of copper plated with iron. Copper is very easily corroded, eating away the tip, particularly in lead-free work; iron is not. Cleaning tips requires the removal of oxide without damaging the iron plating and exposing the copper to rapid corrosion. The use of solder already containing a small amount of copper can slow corrosion of copper tips.

In cases of severe oxidation not removable by gentler methods, abrasion with something hard enough to remove oxide but not so hard as to scratch the coating can be used. A brass wire scourer, brush, or wheel on a bench grinder, can be used with care. Sandpaper and other tools may be used but are likely to damage the plating.