In this post I will talk about soldering irons and how to clean, tin, and maintain soldering iron tip
What is a Soldering Iron?
A soldering iron is a hand tool used in soldering. It is composed of a heated metal tip and an insulated handle. It supplies heat to melt solder so that it can flow into the joint between two work pieces to make a physical bond to component to component, component to board, or component to wire.
In doing so the tip gets hot enough to oxidize quickly, which will become dirty or contaminated just sitting in the soldering iron holder.
The oxidation will then act as an insulator which is not good for heat transfer when working on your project.
The ability for the soldering iron tip to transfer heat is drastically reduced when it gets covered in oxides and burnt flux residues. Not only does heat not transfer as well through this debris, but the contaminants also prevent solder from wetting or sticking to the tip. Most heat transfer goes through a fluid solder “heat bridge” that lies between the iron tip and components, so an iron tip that repels solder will be very ineffective.
The longer oxides and charcoaled flux residues remain on the tip, the harder they become to remove, so it’s a good idea to clean the tip every time you use your iron.
Above are some examples of tips that have not been properly cleaned and tipped.
Wiping the iron tip on a damp sponge can help to remove oxides easier, and allows waste to fall away. A Dry Cleaner (special brass wool) can also be used. It consists of soft metal shavings that are coated with flux. You clean the tip by thrusting the iron into the shaving a few times. By avoiding the thermal shock of touching a damp sponge, these cleaners help to increase tip life, and in my opinion, do a better, faster job. But both are better than not cleaning a tip at all.
Regular cleaning = easier soldering and longer tip life:
After cleaning the tip apply flux core solder to the tip to give it a new coat of solder.
Repeat this step before starting and every few minutes after, apply small amount of fresh solder to the tip. Usually touching the tip with rosin-cored solder will supply enough flux so that oxides can be removed with a damp sponge or dry cleaner.
If this isn’t sufficient, you can purchase "tip tinner, cleaner or also called Heavy Oxidation Removal Paste that are a mixture of solder paste and flux. The flux is oftentimes stronger (more activated) to help remove oxides.
Thrust the iron tip into the tip cleaner a few times till it has an even coat of solder.
If that doesn’t work, a special cleaning polishing bar can be used to salvage extremely bad tips.
Another last resort is to gently rub the oxides off with an emery cloth or soft steel brush. Cover the tip immediately with solder after cleaning to prevent further oxidation.
Never file the tip to clean it or form a different shape. The tips are mostly copper with a protective iron plating, and once that plating is pierced, the tip will die quickly. Copper is used because it’s an excellent heat conductor, but if exposed to solder, it will quickly dissolve into the solder
What the causes of detinning are:
Failure to keep the working end of the tip covered with solder during idling periods.
Operating at high temperatures, which speeds oxidation. Maintain the temperature of
800°F (427°C), or less, whenever possible.
Use of very small solder wire. Its small diameter carries inadequate flux to keep the tip
Lack of flux in the soldering operation. Use of no clean fluxes and low-residue fluxes.
Use of solder with low tin content.
Repair and touch-up, and the use of wick.
Wiping of tips on dry sponges, man-made sponges, rags, paper towels, or metal wool in lieu of a wet cellulose sponge.
To maintain the performance of any soldering iron tip, a simple maintenance procedure is recommended:
- Operate at the lowest possible temperature (800°F (427°C) or lower. Operating at
temperatures exceeding 850°F dramatically increases the formation of iron oxides, which
is one of the major causes of detinning.
For tip wiping: use a dry cleaner brass wool or only (sulfur-free) pure cellulose sponges; damp to the touch.
Add rosin core solder of adequate diameter (.032", .80 mm, or larger) to the working end
of the tip regularly.
If your soldering tip becomes detinned (oxidized), it can be restored in a
number of ways:
With the iron tip cold use a polishing bar. A polyurethane foam bar with embedded abrasives which is used to polish the working end of the tip to remove surface oxides; then immediately re-tin the tip with rosin core solder.
Use Tip Tinner/Cleaner. This is a halide free, solid paste which
provides quick and safe re-tinning and cleaning of oxidized tips.
Just wipe the oxidized tip at normal soldering temperatures into the tip tinner for a few seconds until the bright tinning surrounds the working end of the tip. It’s fast acting, residue free.
Use a conventional solder wire with rosin base flux of sufficient diameter .032" (.80 mm)
or larger, (with a sufficient percentage of flux available) to re-tin the solder tips.
Flood or coat the working end of the tip regularly with solder.