The term solder is defined as uniting or making whole by the process of soldering. Soldering is a process of joining two or more metal items by melting, followed by flowing a filler metal into the joint. During IPC J-STD-001, students learn common solder practices using the tools available. Two of the most common types of solder are lead and lead-free.
What is Lead Solder?
Lead-based solder contains 60% tin and 40% lead and has a melting point of around 360 degrees Fahrenheit. The solder generally comes on a spool in wire form labeled Sn63/Pb37, which indicates the amount of tin and lead the alloy is composed of. When students are learning to solder, they can practice a variety of techniques. Some techniques include soldering wires and terminals, through-hole components, and surface mount components to a PCB or Printed Circuit Board.
What is Lead-Free Solder?
Lead-free solder is the complete opposite of lead soldering. Lead-free solder does not contain any lead. Instead, it will contain other metals such as copper, silver, indium, or zinc to name a few. Lead-free solder has a much higher melting point than regular lead (around 422 degrees Fahrenheit). Due to the toxicity of lead, places in Europe and Asia have either restricted or banned the use of lead in consumer electronics. This is known as being RoHS compliant which stands for Restriction of Hazardous Substances.
Which Solder is Better?
Depending on which task you are trying to accomplish, there are benefits to using both types of solder. Lead-based solder is selected for its lower melting point, faster cooling times, decreased chances of cold solder joints and flows well. On the other hand, the benefits of going lead-free are that complies with RoHS guidelines, does not spread during the reflow process, and there is no rapid stencil wear.
At EEI Training give our students the option to use either lead or lead-free based on what their job requires or preference. For more information on our solder training courses please visit /training/certifications/index.