Ventilation Info & Hacks for Metalsmiths

One of the most important topics for a Metalsmith is safety. First and foremost, you should be protecting your lungs from both dust particles and gas/fumes from burning gas and using fluxes/solders.

Dust particles from sanding, polishing, grinding, application and other situations should be dealt with by wearing a Niosh rated N95 respirator. A couple of suggestions would be the Aura Mask by 3M or the RZ Mask which has replaceable filters. Both masks are very lightweight and will not fog your glasses. The more comfortable, the more you will wear them.


When using gas related equipment, such as a torch, the removal of particles burned off with the flux, solder and gas combusting is very important. This can be accomplished by making sure you have proper cross-ventilation and exchange of air during the use of your torches.

A room in which you use your torches should have a window and door, two doors or two windows to create new air incoming and exiting. You should also further move the air by installing a good vacuum with a vent which pulls the air, directly at the spot of soldering, to the outdoors.

Here is a very good explanation of the concerns with torch soldering, from

One of the most neurologically damaging chemicals is manganese (Mn). Exposure is prevalent in many welding operations. According to the American Conference of Governmental Industrial Hygienists (ACGIH), the threshold limit value for manganese is 0.2mg/m 3 time-weighted-average, yet OSHA’s permissible exposure limit is 25 times higher at 5.0 mg/m3.

However, according to the National Institute for Occupational Safety and Health (NIOSH), levels of manganese less than 0.2 mg/m3 have been known to cause a decrease in brain function and motor skills.

The symptoms (e.g., tremors, shakes, loss of balance, slower response speed, trouble walking, impotency, slurred speech, extreme drowsiness or nighttime leg cramps) are collectively called “manganism” and can be very similar to those of Parkinson’s disease. However, medical evidence linking manganese exposure to Parkinson’s Disease is inconclusive, and it has stirred a controversy in the occupational safety and health community (read “Toxic Smoke and Mirrors”). For further information, read Safety and Health Topic: Welding and Manganese: Potential Neurologic Effects (NIOSH) online.
Manganese is not the only hazard of welding and torch-cutting. The following are some of the toxins listed by OSHA that are released during these operations:

  • Zinc is necessary for protecting metals from erosion as well as the manufacture of brass. When welding with zinc-coated materials, the process gives off a fume called zinc oxide. Inhaling this fume can cause flu-like symptoms known as “metal fume fever.” The exposed worker may experience a high temperature, cough, sweating, chills, nausea, dry throat and fatigue.
  • Cadmium can be found in zinc and is often used to protect steel from rusting. While it shares many similarities with zinc, this substance is far more toxic. OSHA, NIOSH and the Environmental Protection Agency (EPA) find cadmium to be a cancer- causing agent. Inhalation can cause metal fume fever, severe lung irritation and pulmonary edema. If exposed to cadmium over a long period of time, a worker can also suffer from emphysema and kidney damage. Mercury also protects metals from rusting. The government listed mercury as a toxic pollutant in the 1990 Clean Air Act. By federal law, the use of mercury must be controlled to the greatest extent possible via engineering and administrative controls and personal protective equipment (PPE). Its vapor can be released into the air during welding, and when inhaled, it can cause stomach pain, diarrhea, kidney damage or respiratory failure. Long-term exposure may produce tremors, emotional instability and hearing damage.
  • Lead has long been known to be a toxic substance. Welding and cutting metals that contain lead or are coated with lead paint expose workers to dangerous toxins that enter the lungs and blood stream. Elevated levels of lead are commonly called lead poisoning. In the most severe cases, it can cause neurological disorders. Symptoms include a metallic taste in the mouth, loss of appetite, nausea, abdominal cramps and insomnia.

The release of carbon monoxide is also associated with welding and cutting. It is especially dangerous in confined spaces or areas with poor ventilation. Carbon monoxide is odorless and colorless, yet inhalation can be fatal. Mild exposure to this gas can cause headaches, dizziness, ringing in the ears and nausea. High levels of carbon monoxide inhalation can rob a worker’s body of oxygen. For a complete list of welding toxins, including physical and chemical agents, visit the Welding Health Hazards section in OSHA’s online Construction Safety and Health Outreach Program.

The device below was built for the glass-iron-soldering not gas soldering. It has a charcoal filter and helps with the smell of the fumes. It is good in that it pulls air away from you, however for Metalsmiths, you are using a gas flame (butane, mapp/pro, propane, acetylene) so you need to worry about:

  1. Air exchange with incoming and outgoing air flow
  2. Carbon monoxide
  3. Fumes from the gas, solder and flux being removed and not inhaled This is not an adequate tool but it’s better than nothing.

You don’t need expensive equipment but you do need something that moves the right amount of air per your cubic feet of space.

Length x width x height = cubic feet

If you have a 10x10x10 room = 1000 cubic feet

If your fan pulls 390 cfm then a little over 1/3 of your air will be exchanged in a minute. The higher the CFM the faster the air is exchanged, but usually the noise is also more. We want to make an environment where we can work in peace without it causing further issues, like headaches. If you don’t enjoy your space, it will effect the time you work in the space and also whether you will use the vent.

The other important thing is to consider how the vent pulls the air/contaminates away from you. An overhead vent hood often pulls the fumes and by-products of the gas burning off, right past your face. You want these fumes to be pulled away from you at the point of combustion which would be nearest your flame.

So locating your torch soldering station near an area where you can set up a fan and it’s duct work to pull this air out of your studio should be a primary concern when setting up your studio. If you cannot make a hole in your studio wall, then placing your soldering station near a window is the best solution.

There are a couple solutions. If you cannot make a hole in the wall then use your window. You will need a vent (see below), foam insulation tape, a piece of acrylic from the box store cut to fit in the window, laundry vent tubing, and vent tape, and access to electricity to plug in the fan. The fan can go inside or outside.

If you can build in a vent for a planned soldering station, you have more options, but also more cost. The advantage is you can use large propane tanks because only the small camping tanks should go indoors.


Test your vent with incense sticks to see how well the air is being pulled.

Wear a mask/respirator when soldering if you are using products with fluoride or cadmium or other questionable alloys. (See below)

Never torch fire anything with galvanized coating like cotter pins or other materials from the hardware store.

Minimize your exposure to hazardous toxins like using flouride free flux (Prips). Check your hoses often with soapy water or windex, including your connections and hoses.

Use flashback arrestors between your regulator and your hose to minimize risks.

For excellent information and additional source information please consult these two links

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