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Mod - soldering iron

Power socket replacement

A stock soldering iron tends to have a fixed power cord. It is an integral part of the device, cannot be removed, and causes major annoyances during transportation and installation. It is also dependent on the power socket type in a given country.

It was decided to replace the power cord with the IEC C14 connector, allowing use of standard computer power cord instead. Such assembly also allows significant reduction of cabling in the workspace, when the  "Octopus cable" is used.

The soldering iron shell was opened. The transformer was temporarily removed, the power cord was cut, a hole was made in the shell to which the IEC connector was placed, and the connector was soldered to the wires.

Soldering iron

Soldering iron, bottom

Soldering iron, inside, power supply

Soldering iron, inside, control board

Socket dimension check

Socket hole

Socket hole, matching cut on top cover


Wires attached to socket

Wires attached to socket, heat-shrink tubed

Final result

Final result

Thermal insulation of the solder pen

A frequent problem was encountered during work. Plastic and plastic-coated parts, namely plastic enclosures and wire insulation, are sensitive to heat. The soldering iron is hot. When accidentally touching the plastic with the side of the tip or by the sleeve of the heater, a permanent burn mark was frequently left, often requiring replacement of the affected wire or coating the damaged place with insulation paint or a heat-shrink tube.

A solution to lower the surface temperature of the soldering iron was devised: a thermal insulation. Such insulation limits the heat flow from the heater and tip to the outside, and normal ambient air cooling is then sufficient to keep the surface temperature low enough to prevent more substantial damage to accidentally touched surfaces.

A self-adhesive glass cloth strip, used for door insulation in wood and coal stoves, was chosen for the surface coating of the heater sleeve. A length of the tape was cut and wrapped along the sleeve, which it almost perfectly covered. To prevent fraying and to seal the gap, the cloth was saturated with water glass. The cloth was then wrapped with thin copper wire to avoid detaching.

Part of the iron tip was also coated. A narrower piece of a self-adhesive tape was used. The tip was wrapped in a way similar to the sleeve; a thinner layer was used as the maximum outer diameter was limited by the hole in the sleeve skirt, in order to maintain tip replaceability. The cloth was also wrapped with wire and saturated with water glass.

The assemblies then were dried, then baked for about two hours using the soldering iron itself, ramped through a range of temperatures up to about 400 °C, spending most time at around 300-350 °C.

The water glass foamed somewhat, creating fragile but nicely insulating glass foam. The cloth with the water glass formed a fairly compact composite material. The binder and polymer layer from the cloth adhesive side was decomposed during baking, and created a fairly bad stink, only partially mitigated by opening the window. The decomposition products also slightly discolored the formerly pristine-white glass cloth.

The resulting insulation coating greatly reduces the extent of damage caused by accidental touch on plastic surfaces. At common soldering temperatures, a brief contact now causes only a slight mark instead of an extensive damage.

Soldering iron pen

Soldering iron pen, detail

Soldering iron pen, parts

Insulation cloth, before wrapping

Insulation cloth, after wrapping

Insulation cloth, around tip

Insulation cloth, soaked with water glass

Insulation cloth, tied with wire

Insulation cloth, after burn-in

Insulated soldering iron and tip, detail

Insulated soldering iron and tip, detail

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