Irons, Stations, Tips and Hot Air

Types of iron and station

The iron is the tool that delivers heat to the joint. The right one is not the most powerful but the one that holds its temperature when it touches a cold joint. A good station costs little more than a good pencil iron and makes every joint easier.

Type	How it works	Good for	Limits
Fixed-wattage pencil iron (15 to 40 W)	Heater runs all the time; temperature floats with load	Occasional hobby work	No control; tip can overheat or droop; poor with big joints
Temperature-controlled station (40 to 80 W)	Sensor in the tip, controller adjusts the heater	General electronics, repair, lead-free	Needs a stand; reasonably priced
Cartridge system (JBC, Hakko T12, Weller) 60 to 150 W	Heater and sensor inside the tip, very low thermal mass	Production, fast recovery, heavy joints	Dearer; tips are the consumable
Battery or USB-PD iron (e.g. 65 to 100 W)	Small cartridge powered from 12 to 20 V	Field repair, portable work	Limited by the supply; some run cooler under load
Hot-tweezer (SMD tweezers)	Two heated tips close like tweezers	Removing and placing chip parts	Special tool
Hot-air station (see below)	Heated airflow through a nozzle	SMD reflow, desoldering, heat-shrink	Can blow parts away; needs practice
Soldering gun (100 to 250 W)	Transformer heats a copper loop	Heavy wire and lugs, sheet metal	Not for electronics: the field can damage parts
Butane / gas iron	Catalytic or flame heater	Field work, plumbing, large joints	Poor control; uncontrolled temperature

Power, thermal mass and recovery

The tip stores heat in its own mass. Touching a joint pulls that heat out and the tip temperature droops until the heater catches up. A small thermal mass droops more; a large one stays hot; a powerful heater recovers faster. A cartridge has a tiny mass and a powerful heater placed right next to the sensor, so it recovers within a second; a cheap pencil iron has a heavy, slow-heating element.

ΔT_droop = E_joint ÷ C_tip and t_recover = ΔT × C_tip ÷ (P − P_loss)

Iron	Heat capacity	Heater	Heat-up to 350 °C	40 K recovery
Small pencil iron (tip and element)	8.0 J/K	25 W	137 s	16.8 s
Soldering station, long-reach tip	4.5 J/K	60 W	27 s	3.3 s
Cartridge (heater in the tip)	1.2 J/K	75 W	6 s	0.7 s

Take the heat capacities as typical; the pattern matters. The heat-up time is the best practical test of an iron’s thermal mass.

Choosing the temperature

Set the tip to the lowest temperature that makes a joint in one to three seconds. Hotter than necessary shortens tip life, burns flux and lifts pads; cooler makes you hold the iron on the joint for longer, which does more damage. A good starting point is 320 to 350 °C for leaded solder and 350 to 380 °C for lead-free, rising for large thermal mass (up to 400 °C) and falling for heat-sensitive parts.

Job	Leaded	Lead-free	Notes
Small SMD, fine pitch, 0402	300 to 320 °C	330 to 350 °C	Small tip; short contact
Through-hole parts	320 to 350 °C	350 to 380 °C	Standard
Ground-plane pins, heavy wire	350 to 400 °C	380 to 420 °C	Large tip; preheat the board
Heat-sensitive parts (LEDs, sockets)	280 to 320 °C	320 to 350 °C	Heat sink on the lead
Desoldering and rework	350 to 380 °C	380 to 420 °C	Add flux
Low-melting bismuth solder	200 to 250 °C	n/a	Separate iron

• Check the real tip temperature with a thermocouple tip thermometer; the dial can be off by 20 to 50 °C, especially on cheap irons, and an iron’s own sensor reads the sensor, not the tip face.
• Do not leave the iron at a high temperature idle: use the sleep or standby mode, since a hot idle tip oxidizes and burns off its tinning in minutes.

Tip shapes and sizes

Choose the tip by the joint, not by habit. The tip should be about as wide as the pad it heats, so that its face contacts the pad and the lead together; a tip that is too small is slow and a tip that is too big bridges pins and burns the board.

Tip	Contact	Use
Conical (pointed)	Small point	Precision work, tiny parts. Poor heat transfer: avoid for general work.
Chisel / bevel (1.5 to 3 mm)	Flat face	General through-hole and SMD; good heat transfer
Hoof / bevel with a well	Flat with a solder reservoir	Drag soldering fine-pitch ICs
Knife	Long straight edge	Drag soldering rows of pins, wire
Bent / angled	Offset	Working in tight areas
Large chisel (4 to 6 mm)	Wide flat	Heavy wires, lugs, ground planes

Tip care: tinning, cleaning and life

Most tips are copper coated with iron plating (which resists attack by the tin) and a chrome or nickel layer to keep the solder off the shank. The working face must stay tinned, i.e. covered with a thin bright film of solder, because a bare, oxidized tip does not transfer heat.

• Tin before heating long: on first use, heat the new tip to temperature and cover its face with solder and flux at once.
• Clean on brass wool rather than a wet sponge: wet sponges chill the tip and cause thermal shock; brass wool keeps the temperature and removes oxide.
• Tin before parking: before you put the iron down for more than a minute, leave a blob of solder on the tip, which protects the face from the air.
• Never file or sand an iron-plated tip: that removes the plating and the tip dissolves quickly. Use tip cleaner paste on a blackened tip.
• Do not bend the tip or use it as a lever; do not leave it set above 400 °C.

Tip wear by tin attack is strongly temperature-dependent. A common rule of thumb is that life roughly halves for every 25 K above a base temperature:

Tip temperature	Relative tip life	Versus 350 °C
320 °C	1 000 hours (relative)	2.30×
350 °C	435 hours (relative)	1.00×
380 °C	189 hours (relative)	0.44×
400 °C	109 hours (relative)	0.25×

The figures are a rule of thumb, not data for a particular tip, but they show the economy of the lowest workable temperature.

Hot air and other tools

A hot-air station blows heated air through a nozzle to melt solder on many pins at once. It is the standard tool for SMD rework and for small-batch reflow. The air is heated by an element and pumped by a small blower; the main controls are the air temperature and the airflow.

P = ṁ × c_p × ΔT

Airflow	Mass flow	Heat carried at 350 °C
5 L/min	0.10 g/s	33 W
15 L/min	0.30 g/s	98 W
30 L/min	0.60 g/s	196 W

• Use low airflow with a larger nozzle so that small parts are not blown off the board; turn the temperature up rather than the flow.
• Preheat from below with a plate or a second hot-air blower on large boards; it avoids the board warping and the large temperature difference.
• Protect neighboring parts with Kapton tape or foil, and keep plastic connectors away from the stream.
• Other tools: a preheater (infrared or ceramic plate) for large or multilayer boards; desoldering stations with vacuum; solder-fume extractors; and a microscope (see rework on Rework, Desoldering and Repair).

The bench set-up

• Light and magnification: 1 000 lux or more on the work (a bright adjustable LED lamp), and 3 to 10× magnification for SMD parts; a stereo microscope is the best upgrade.
• Holding: a PCB vise or “third hand” so the work does not move; a heat-resistant mat.
• Fume extraction at the work: a small fan with a carbon filter, or a hose (see Soldering Safety, Fumes and ESD).
• Stand and cleaner: a heavy iron stand with brass wool or a damp sponge.
• Static control: an ESD mat and wrist strap if you handle sensitive devices (see Soldering Safety, Fumes and ESD).
• Consumables: solder wire of two diameters, flux pen, desoldering braid and pump, isopropyl alcohol and brush, tweezers, flush cutters.
• More on the bench and tools: Shop Tools.

Troubleshooting

Symptom	Likely cause	What to do
Tip will not take solder (black)	Oxidized, burnt or worn plating	Clean with tip cleaner, retin; replace if the iron plating is gone
Iron is hot but joint is slow	Small tip, dirty tip, big thermal mass	Larger tip, clean and tin, preheat, add flux
Joints are good then suddenly poor	Tip has cooled in use (droop) or is sleeping	Check standby setting; use a higher power iron
Solder smokes a lot	Tip too hot	Lower the temperature and extract
Hot-air blows parts away	Airflow too high	Lower flow, bigger nozzle, hold the part with tweezers
Temperature reads wrong	Uncalibrated sensor or worn tip	Check with a thermocouple thermometer; replace the tip

Related

• Soldering: the overview of this guide.
• How Soldering Works: the heat energy per joint.
• Through-Hole Soldering and Surface-Mount Soldering: using the tools.
• Shop Tools: the bench.

FAQ

What wattage soldering iron do I need?

For electronics, a temperature-controlled station of 40 to 80 W is ample. What matters is how quickly it recovers, not the number of watts: a 60 W cartridge outperforms a 100 W simple iron.

Why is my tip turning black?

The plating is oxidizing because the tip was left hot without solder, run too hot or cleaned badly. Retin it with solder and flux, clean it on brass wool and lower the temperature.

Brass wool or a wet sponge?

Brass wool is gentler: a wet sponge chills the tip and cycles it through thermal shock, which shortens its life.

What tip temperature for lead-free?

About 350 to 380 °C, adjusting up for large joints and down for sensitive parts, as low as will make a joint in one to three seconds.

Do I need a hot-air station?

Not for through-hole work. For surface-mount rework and for removing multi-pin chips it is the right tool and worth having.

References

• Manufacturers’ tip and station data (Hakko, JBC, Weller, Metcal); IPC J-STD-001.
• Lee, N.-C., Reflow Soldering Processes and Troubleshooting, Newnes.
• Horowitz, P. and Hill, W., The Art of Electronics (soldering notes).

Last reviewed: October 2026. Heat capacities, powers and tip-life figures are typical; use your iron’s data sheet.