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Soldering Equipment

Two types of soldering equipment are soldering iron and instant heat soldering gun. Most soldering irons are of pencil type construction and range in heater output power from 15 to 250W. A 40 to 60W soldering iron is suitable for small electronic work, for example, soldering components to PCB. A 60 to 100W iron is suitable for larger electrical work, for example, wiring mains cord to connector. The cordless soldering irons used for field work are either powered by rechargeable batteries or by butane gas. The transformer isolated, grounded tip soldering irons with 12 or 24V heating elements are used for electrostatically sensitive electronics work, for example, soldering MOS devices. The temperature controlled soldering irons are employed for precision temperature sensitive soldering work, for example, soldering flatpac micro-controller chip onto PCB.

The soldering iron tip transfers thermal energy from heater to the soldering connection. Most tips are some copper alloys for their excellent thermal conductivity. The tips are available in different shapes and sizes suitable for different types of work. For fast and optimal heat transfer, the tip should be of the largest possible diameter and the shortest reach suitable for the type of job. The mains powered soldering iron tips are usually connected to GND for operator and component safety. The grounded tip protects voltage and current sensitive components.

The soldering tip temperature is usually set between 700 and 800 deg. F (370 to 425 deg. C). This is substantially higher than melting point of most solders (400 deg. F). Using a higher temperature stores heat in the tip which speeds up the melting process and allows proper formation of intermetallic layer of the parts and solder.

The soldering iron you will be using in the lab. is Weller WTCPT (manufactured by Cooper Tools, Australia) mains powered, transformer isolated and temperature controlled.

A ferromagnetic temperature sensor attached to the tip and a permanent magnet inside the pencil in close proximity with the sensor are used for ON-OFF temperature control. The heater is rated at 24V/48W and the tip used is 1.6 mm screwdriver type having temperature rating of 700 deg. F (The bottom end of the tip is marked with '7')

For care and safe use of soldering equipment, Thou shall learn and follow without fail Ten Commandments:

1.

Thou shall not remove tip from soldering iron when power is On. Causes heating element to rise in temperature to approximately 1300 F resulting in thermal shock and reduced heater life.

2.

Thou shall maintain a damp (NOT drenched) iron sponge (preferably with de-ionized water). A drenched sponge will bring the temperature of the tip down too drastically, causing thermal shock and reduced tip life.<

3.

Thou shall not disconnect soldering iron from base unit when power is turned On. Disconnecting or reconnecting the soldering tool from the base unit with power applied may cause a short between non-compatible pins resulting in damage to the base unit or pencil.

4.

Thou shall maintain a coating of solder on working area of soldering iron tip. Protects the tip from oxidation.

5.

Thou shall never drop soldering iron while heated. Dropping the soldering tool while heated may cause thermal/mechanical shock to the heater, sensor, or tip (fractured plating).

6.

Thou shall not throw soldering iron into soldering tool stand. See Commandment 5.

7.

Never use soldering iron as a crowbar or pry tool. Could chip or pit finish on tip rendering it useless.

8.

Using sharp or serrated objects to remove tip from soldering iron is forbidden. See Commandment 7.

9.

Honor thy KGB (Known Good Base). Do not plug a non-working soldering iron into a KGB. Could cause damage to the base.

10.

Thou shall turn station down to lowest setting during daily usage when not being used. Turning the station down during non use periods will prevent severe thermal cycling of the tool. However, tools not being used for extended periods of time should not be left on indefinitely.

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