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Brazing is sometimes confused with welding (or soldering), as these processes involve joining metal pieces together. Both brazing and welding uses molten filler metal to join metals. The main difference between the two processes, however, has something to do with temperature. Brazing is done at much lower temperatures than welding. Brazing uses filler metals whose melting points are between 840 and 10,000 degrees Fahrenheit (1).
Both processes emit sufficient amounts of heat and ultraviolet radiation to be hazardous, but brazing does so at a much less intensity. So the question is whether it’s necessary to wear a welding mask or helmet when brazing.
Brazing is generally less hazardous than welding for a number of reasons. It doesn’t produce as much sparks and spatter as welding does. Also, it is done at much lower temperatures, and while it may produce intense light and heat, it doesn’t produce as much ultraviolet radiation as arc welding does. These do not mean that you can slack off on precautionary measures. In fact, OSHA still recommends wearing helmets and respirators for brazing.
Cadmium is one of the most toxic industrial substances. The International Agency for Research on Cancer and the Environmental Protection Agency classify it as a carcinogen. Using cadmium in brazing exposes you to fumes that cause flu-like symptoms. These symptoms include fever and muscle aches, hence often called “cadmium blues.” Although these symptoms disappear in a week, bronchitis and pulmonary edema can be a result of severe exposure due to inflammation. When you inhale cadmium fumes, the linings of your respiratory passages get inflamed. A cough is usually the first sign of inflammation. But systemic assault caused by cadmium may cause headache, dizziness, lethargy, and chills.
On the other hand, when lead is used in brazing, the likelihood of inhaling lead fumes is high. Lead fumes can be minimized by melting lead below 900F. But since brazing is done above 840F, it’s unavoidable to go beyond 900F and release lead fumes. Lead oxide also tends to settle on surfaces. If you see yellowish or brownish dust in your weld area, that’s lead oxide, a neurotoxic substance. Meaning, it harms your nervous system. In addition, it has long-term effects on your gastrointestinal tract and kidneys.
Exposure to too much lead can cause poisoning. Acute lead poisoning has neurological consequences that produce symptoms such as pain, muscle weakness, numbness, and tingling. In severe cases, it causes brain inflammation. Abdominal symptoms (e.g. abdominal pain, nausea, vomiting, and diarrhea) are not uncommon.
Ways to Mitigate Brazing Hazards
Two types of ventilation done to control the concentration of fumes and gases in welding and brazing are general ventilation and local exhaust ventilation.
General ventilation works by diluting airborne contaminants. This is done in two ways:
- Keeping doors and windows open
- Installing fans to promote circulation of air and prevent accumulation of air contaminants in an area
General ventilation is good for moderately hazardous fumes and gases. The purpose is to dilute, if not eliminate, fumes and gases from your breathing space.
Contrary to a common misconception, ventilation is not always unnecessary when working outdoors. If there’s a breeze blowing, you can stay upwind to avoid fume and gas inhalation. If that’s not possible or if there’s no wind blowing (and you run a risk of inhaling contaminants), mechanical ventilation or wearing a respirator is your next option.
Local exhaust ventilation, on the other hand, is more effective than general ventilation because it doesn’t blow away contaminants but captures them. Hoods and ducts suck out fumes and gases from your breathing zone. The hoods can be placed close to you to immediately capture the fumes and smoke and produced by your brazing torch.
Brazing PPE, which serves as an adjunct to ventilation, includes body, eye, and face protection. Basic body protection involves flame resistant clothing that provides sufficient coverage. The purpose is to reduce risk of skin burns caused by sparks or the flame itself. Welding gloves and aprons are also necessary.
However, to address the initial question, which is the title of this article, again, you can’t go wrong with a complete set of protective gear, including a welding helmet or mask and a respirator. If a helmet seems like an overkill, you still need to wear welding goggles or glasses with shade 3-4 lenses. For respiratory protection, exhaust hoods are almost always necessary. Airline respirators may be needed in confined spaces when significant levels of cadmium and lead or other contaminants are present. If you’re doing brazing outdoors, you should wear mask respirators that filter fumes, vapors, and gases.
Additional Safety Measures
Brazing filler materials that contain significant amounts of cadmium should have labels that say so. Also, fluxes that contain fluorine compounds should have the same precautionary labels. In any case, avoid inhaling the fumes!
Welding Respirators Review
There are a range of outstanding welding respirators that are on the market today. We have compiled the Welding Respirators Reviews that we consider essential reading for those of you looking to find a good quality respirator.
Most of the welders you know probably forgo welding masks or hoods for some reason. Welding helmets are bulky. They can limit your mobility. Besides, brazing isn’t as hazardous as welding. Then again, brazing is still dangerous without appropriate protective gear. OSHA has set rules and recommendations for welding and brazing for your safety. If you’re an employee and brazing is one of your jobs, your employer should be responsible for ensuring a safe working environment and providing you your PPE.