Soldering Safety and Procedures

Import Safety Notes:

When soldering, safety glasses, lab coats, and long pants must be worn as Personal Protective Equipment (PPE).  More details on soldering safety which MUST be followed can be found through EHRS (Link).

Hazards
Soldering poses three main hazards:  

1. Burns and Fire The soldering iron, soldered joints, and soldering dross are sources of heat. The soldering iron tip can reach very high temperatures and will cause severe burns if touched. Soldered joints, molten solder, and soldering dross are initially hot and can cause burns until fully cooled.  The soldering iron can cause fires if it touches combustible or flammable materials.  

2. Flux/Rosin Fume Exposure Some solders contain rosin flux that generates smoke when soldering. The smoke contains chemicals and particles that can be irritating to the eyes and respiratory system. 

3. Lead and Other Metal Exposure Some solders contain lead (Pb) metal. Lead is a probable carcinogen and is a toxicant to multiple body systems. Chronic exposure to lead can lead to various health effects, including neurological effects such as decreased memory, learning and attention, weakness in extremities, anemia, kidney damage, cardiovascular effects, digestive issues, reproductive effects, and cancer.   Other metals used in solders (such as tin, silver, and indium) are less toxic than lead but still pose potential health hazards, particularly when ingested.  

Prevention of Hazards

Tips for Preventing Burns and Fires:

• • Ensure that your work surface is fire-resistant and that no flammable materials, such as paper bags or towels, are present near the work area. 

  • Check the condition of the soldering iron tip and replace it if it has visible damage. Check the condition of electrical wires and replace the soldering iron if the wiring is damaged.

  • Ensure that the work area is clear of power cords; touching a soldering iron to a power cord can cause electrical shock or burns.  

  • Never touch the soldering iron tip, soldered joints, or soldering dross on the benchtop. If the soldering iron falls during use, do not attempt to catch it.  

  • Ensure that cleaning sponges used on the iron tip are sufficiently wetted.  

  • Always place the soldering iron in its stand (holder) when not actively using the iron. Ensure that the iron is turned off and unplugged when not in use. Do not leave the soldering iron station unattended while the iron is on or cooling.

  • Make sure to wear proper PPE (as outlined above)

• Tips for Preventing Flux/Resin Fume Exposure

• Do not place your face directly in the path of soldering smoke. 

• Ensure that the work areas where soldering is performed are well-ventilated. Use a benchtop soldering smoke extractor with activated carbon filters or a dedicated exhaust snorkel to draw soldering smoke away from the person soldering. 

Tips for Preventing Lead and Other Metal Exposure

• The primary route of exposure to lead and other metals from soldering is through ingestion.  

• Ingestion occurs through accidental introduction of metals to the mouth via contaminated hands during contact with food, drink containers, smoking, or other hand-to-mouth behavior. 

• Skin contact with lead is considered harmless unless lead on the skin is later ingested. 

• Inhalation of lead and other metal fumes does not pose a significant exposure risk since solders are not heated to a high enough temperature to create a metal fume.

• THIS LAB WILL ONLY USE LEAD FREE SOLDER

• Maintain a hygienic work environment 

  • Wash your hands thoroughly with soap and water after soldering to prevent hand-to mouth metal exposure.  

  • Never use compressed air or dry wipes to clean contaminated work surfaces.  

  • Do not store or consume food and drink in the space where you are soldering. 

Leaded Soldering Waste Disposal

• Leaded soldering waste must be disposed of in a container with a lid. The container must have a yellow hazardous waste tag. 

Soldering Procedure

Please follow along with the procedures provided in the following links

1. How to solder in lab (BE labs instructions)

2. How to solder (Link to Sparkfun website)

3. Soldering Metal, Gold, and Circuits (Link to Daniel Gleich's Guide)