I have been doing a lot more soldering in the past two years than I have ever done.  I’ve learned some new things during this time.  Some of it contradictory.  Some of it I didn’t know why, such as being told to use copper curls instead of a damp sponge to clean my soldering iron tip.

So I’ve “read the literature” and from my research compiled a list of things you can do to keep your tip in good condition as long as possible.  Some of my tips you may choose to ignore to make your life more convenient at the price of buying new tips more often. That’s fine of course. But at least now it will be a more informed decision.

Like tires on a car, a soldering iron will inevitably wear out with use.  And like balancing and rotating the tires on your car, there are ways to make your soldering iron tip work better and last longer.

First, a bit about the construction and theory behind a soldering iron tip.

A soldering iron tip is made of a copper core that conducts heat well, plated with a relatively thin layer of iron to prevent erosion of the copper.  Oxidized iron does not conduct heat well and will not wet with solder.  Iron oxidizes rapidly at the high temperatures used during soldering.  The iron needs to be protected from corrosion with a coat of solder which contains tin. 

We often call protecting the tip with a fresh coat of solder “tinning”.    An iron tip coated with molten solder is referred to as “wet”.

Tips for taking care of your soldering iron tips:

1. If nothing else, always re-tin your iron just before placing it back in the holder.  The #1 mistake most people make is not adequately protecting the tip with solder while it is resting in the holder.
2. Lower the temperature or turn off the iron if you won’t be using it for several minutes.
3. Use the lowest temperature you can for soldering.  High temperatures accelerate oxidation and other wear-out mechanisms by up to 2X.  The required temperature varies depending on iron, tip construction and size, technique, and type of device you are soldering. Here are some guidelines:
   • For SnPb 63/37 solder, under 340C (650F) should be used.  I use 315C for hand soldering surface mount parts.
   • For lead free solder, use 360C to 385C (680F to 725F)
4. Use “metal wool” or “copper curls” instead of a wet sponge to clean the tip.
   • The thermal shock of placing a hot tip on a wet sponge causes tiny fractures in the iron plating. This leads to openings that allow the interior copper to oxidize and erode.
   • It is easy to remove too much of the solder coating from the tip using a sponge.
   • The cooling effect of the wet sponge can make it harder to remove flux residue.
   • Using tap water (instead of distilled water) can leave mineral deposits on the iron, resulting in an unwettable tip
5. If you use a sponge, only use clean sponges made specifically for soldering.
   • A dirty sponge will collect contaminants that will react at high temperatures, damaging the tip.
   • A typical “store bought” sponge often contain sulfur or plastic that cause corrosive by-products when heated to soldering temperatures.
6. Use rosin core “RMA” solder and flux.
   • Water soluble is too corrosive.
   • No-clean has difficulty keeping oxidation off the tip.
7. A badly oxidized tip will have a black or brown scale coating.  Rosin activated flux can be used to clean the tip.  Follow with a fresh coating of solder. Alternatively, use a tip cleaner that contains tin plus a de-oxidizing agent.
8. Never use an abrasive material such as sandpaper, emery cloth, scotch-brite, or a dry sponge to clean a tip.  This removes iron from the tip, drastically reducing tip life.
9. Avoid the drag solder technique. It is like running the tip across a metal file.
10. Do not use the tip to lever a part off during desoldering.  This can fracture the iron coating. Use a soldering tool.
11. Do not apply excessive pressure or scrub the tip against a joint. This causes wear and does not aid heat transfer. Tin the tip and use additional liquid flux if necessary. 
12. Do not bang the tip against the table to remove SMT parts or excess solder.  In addition to the shock causing fractures in the tip’s iron coating, this can also damage the soldering iron’s heater.
13. Avoid striking the tip against the metal holder when placing the soldering iron back in its holder.
14. If possible, use lead based solder.  The high tin content of lead free solder causes migration of the iron coating on the tip into the solder.  Migration plus higher temperatures needed for lead free solder can reduce tip life by 4 to 5 times relative to lead alloy solder.