Lead-Free Soldering 230

This class covers the specific characteristics, flux requirements, and thermal profile of lead-free solders, as well as the proper techniques to apply when using these new solder materials. Includes an Interactive Lab.

  • Difficulty Intermediate

  • Format Online

  • Number of Lessons 13

  • Language English


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Course Outline
  • Objectives
  • What Is Lead-Free Soldering?
  • What Is Lead-Free Solder?
  • Flux for Lead-Free Soldering
  • Advantages of Lead-Free Soldering
  • Disadvantages of Lead-Free Soldering
  • Hand Soldering with Lead-Free Solder
  • Lead-Free Soldering: Thermal Profile
  • Lead-Free Soldering: Proper Heat Transfer
  • Effects of Lead-Free Solder on Soldering Iron Tips
  • Characteristics of a Good Joint
  • Common Lead-Free Soldering Defects
  • Summary
  • Define lead-free soldering.
  • Define lead-free solder.
  • Describe flux used for lead-free soldering.
  • List the advantages of switching to lead-free soldering.
  • List the disadvantages of switching to lead-free soldering.
  • Describe the impact of lead-free solder on hand soldering.
  • Describe the thermal profile for lead-free soldering.
  • Describe proper heat transfer for lead-free soldering.
  • Describe the effect of lead-free solder on iron tips.
  • List characteristics of a good joint.
  • Describe common lead-free soldering defects.
Vocabulary Term


A uniform mixture of two or more materials. One of the materials must be a metal.


A chemical compound with both chlorine and fluorine, formerly used as refrigerants, propellants, and cleaning solvents. Chlorofluorocarbons were banned because of their negative effects on the ozone layer.

cold joint

A dull, poorly soldered joint that does not provide good conductivity.


A measure of a material's ability to conduct current.

contact angle

The angle at which a liquid meets a solid surface. In soldering, contact angle is measured as the distance between the soldering iron and the surface being soldered. Decreased contact angles encourage proper wetting with solders.


A chemical solid, liquid, or gas capable of irreparably harming living tissues or damaging material on contact. Corrosive chemicals include acids and certain organic materials.

eutectic point

The lowest temperature at which a substance will melt.


A substance which facilitates soldering, brazing, and welding by chemically cleaning the metals to be joined.

flux pen

A flux application tool, usually shaped like a marker pen, that channels controlled amounts of water-soluble flux onto metal surfaces.

fume extractor

A device designed to remove harmful fumes caused by solder and flux from the soldering workstation by filtering the air.

good joint

A properly soldered joint that provides good conductivity.


A highly reactive, highly corrosive compound that attacks dirt and bacteria. Chlorine and flouride are common halides.

heat transfer

The passage of thermal energy, i.e. energy in the form of heat, from a hot to a cold body.


Jagged extensions or spikes protruding from a soldered joint. Icicles can be caused by an iron that is too cool.


A soft, heavy, toxic, and malleable metal often used in solder. Because of the serious health hazards associated with lead exposure, there is a growing movement to eliminate lead from all consumer products.

lead-based solder

Solder that contains more than 0.2% lead. Lead-based solder has been the standard soldering alloy for the past several decades.

lead-free solder

Solder that contains less than 0.2% lead. Lead-free solder has different properties and appearance than lead-based solder. Lead-free solder is dull and grainy, and requires hotter soldering temperatures.

lead-free soldering

Soldering with metal alloys that contain only trace amounts of lead, or no lead at all.


A specific flux classification. Composition is organic (OR) with high activity (H) and the presence of a halide (1).


A material's chemical reaction with oxygen. Oxidation causes rust and tarnish to form on metal surfaces and also prevents solder from properly bonding to surfaces.

Pb-free solder

Solder that contains less than 0.2% lead. Pb is the atomic symbol for lead.


Tinned by the manufacturer before the tip has ever been used.


Tin (Sn), silver (Ag), and copper (Cu). This is one of the most commonly used lead-free alloys.


Tin (Sn) and copper (Cu). This is one of the most commonly used lead-free alloys.

surface tension

An effect within the surface layer of a liquid that causes that layer to behave as an elastic sheet. This effect allows insects (such as the water strider) to walk on water, and causes capillary action.

thermal profile

The range of temperatures involved in a heating process.


Poisonous or harmful. Many substances can be harmless with small amounts of exposure and toxic with large amounts of exposure.

water table

The water table is found underground. Rock and soil are saturated with water that can feed or seep into wells or other water sources used by people for drinking.


The ability of a liquid to spread out over a surface.


The behavior of a liquid when the liquid contacts a solid surface. Liquids with poor wetting ability tend to form droplets, while liquids with good wetting ability tend to spread out evenly over the solid surface area.


A crystalline metallurgical phenomenon whereby metal grows tiny, filiform hairs. The effect is primarily seen on elemental metals but also occurs with alloys.


Capillary action that draws a liquid up and away from a surface.