Soldering is the process of combining two metals via a third metal (the "joint") with a lower melting point than the base metals. In this procedure, the two base metals are not distorted and only the filler metal is melted. The filler metal is made up of a combination of substances, generally, 60% tin, 40% lead and a wetting agent to aid solder flow, called flux.
Flux is a chemical cleaning agent that is used in conjunction with solder in order to remove oxidation from the base and filler metals involved in soldering. This process improves the overall flow and effectiveness in the merging of the metals.
Colophony, the base product of flux, is a translucent, amber-colored rosin that is abstracted when turpentine is distilled from the resin of pine trees. It is composed of roughly 90% resin acid and 10% neutral material. When the flux is heated, colophony generates fumes including, but not limited to, aliphatic aldehydes, hydrochloric acid and other gases containing benzene, toluene, styrene, phenol, chlorophenol and isopropyl alcohol.
Soldering fumes (also known as soldering smoke) are hazardous fumes that are generated from the process of melting down the flux past its boiling point. When the flux is melted down, its state goes from solid - to liquid - to gas (the “Solder Fume”).
When your soldering iron is set, it usually runs between 300 and 400 degrees C, and although solder is made up of tin and lead, the temperature at which they melt is still not enough to heat the metals to their boiling point and turn them into gas (Tin boils at 2603 degrees C, and Lead boils at 1750 degrees C). This difference in temperature would indicate that the majority of fumes are being applied from the boiling of flux.
Yes. These hazardous fumes often contain many chemicals that can cause immediate and long term respiratory and skin irritation, including, but not limited to, eye, throat and lung irritation, nose bleeds and headaches.
Weller, a manufacturer of soldering products (among other items), explains that "at least 20% of the employees working in the soldering area show clinical symptoms of asthma caused by the work environment" in studies that have been done on workers mostly in the United States and England in the electronics industry.
WARNING: THIS PRODUCT CONTAINS LEAD AND MAY CONTAIN OTHER TOXIC METALS OR CHEMICALS. Ingestion or inhalation of fumes or particles released through processing could cause lead poisoning or cancer. Absorption of lead is known to cause birth defects and other reproductive harm and may result for example in damage to the blood and neurological systems. Use only with adequate ventilation. Use NIOSH approved respiratory protection when necessary. Wash thoroughly before eating, drinking or smoking. Not for use in portable water service systems...
On some occasions lead oxide can be introduced through the soldering process, creating an exposure to lead oxide fumes can be extremely hazardous and result in lead poisoning. Lead poisoning often includes symptoms such as indigestion, nausea, constipation, severe abdominal cramps, loss of appetite and headaches or even migraines.
Because of the high risk of worker/operator exposure during soldering, OSHA suggests Ventilation as a key to controlling lead exposures:
"Ventilation, either local or dilution (general), is probably the most important engineering control available to the safety and health professional to maintain airborne concentrations of lead at acceptable levels. Local exhaust ventilation, which includes both portable ventilation systems and shrouded tools supplied with ventilation, is generally the preferred method. If a local exhaust system is properly designed, it will capture and control lead particles at or near the source of generation and transport these particles to a collection system before they can be dispersed into the work environment."
The type of soldering [e.g. Hand Soldering, Wave Soldering, Reflow Soldering, Production Soldering, Maintenance Soldering, Pipe Soldering, Mechanical & Aluminum Soldering, Resistance Soldering, Stained Glass Soldering, etc.] being performed by the operator directly determines the size, configuration, and air volume that the fume extractor will require in order to be effective. Certain applications can release more fumes or may be spread out over a larger surface area; which may require a more powerful fume extraction unit.
Sentry Air Systems offers a large variety of solder fume extractors, including Series 100 options (with the lowest air volume rating), and Series 450 options (with the highest airflow rating of up to 950 CFM).
This question also determines whether or not you may need features like ESD-Safe Fume Extraction. For those working on applications that need to be protected from Electrostatic Discharge, such as electronic soldering, this feature may be a primary requirement as you search for a solder fume extractor.
If your process calls for an ESD-Safe unit, take a look at the Model 100 Stainless Steel Solder Sentry, which is an ESD-Safe benchtop fume extractor.
Do you solder 8 hours a day, 5 days a week? Or do you solder for a half an hour once a week? The amount of time spent soldering should be taken into consideration when choosing an appropriate fume extractor. Extractors with more powerful fans, larger filter media, and pre-filtration should be selected if soldering is performed on a regular basis.
A large part in determining what type of solder fume extractor is a good fit for your workstation can be based purely on size. Can your benchtop workspace accommodate a fume extractor? If you don’t have room on your benchtop, would you prefer a wall-mounted unit to hover over your work area or a floor unit that reaches your work area via flexible hose?
The Occupational Safety and Health Act of 1970 states that "employers are responsible for providing safe and healthful workplaces for their employees."  It is the employee’s right to inform the employer of workplace health hazards like poor ventilation during soldering. (The Whistleblower Protection Program protects employees who raise health and safety issues to their employers).
Sentry Air Systems, Inc. provides this information as a customer service, but cannot be responsible for its accuracy or completeness. It is recommended that competent legal authorities as well as safety and hygiene professionals be consulted.