Yet another fun post from the world of Halldor the Viking! Seriously, I know ‘elf and safety is not exactly the most enthralling of subjects, but regarding certain aspects of bone working with modern tools it is pretty important. The vast majority of the safety concerns are blatantly obvious and easy to address or avoid – e.g. saws, knives, axes etc are sharp so be careful! hot oil/water (for moulding horn) is hot so be careful! and so on.
However, one particular area is quite important and not so simply dealt with – dust. When working bone in a traditional manner, the dust is never really an issue as most shaping uses blades, and even a lot of finishing can be done with a knife. Additionally, most smoothing of items using pumice, ash, sand etc takes place at low speed and never really creates a dust cloud or fine particles. Modern machinery though is both a blessing and a curse – bench mounted grinders and sanders can speed up the shaping process for many items immensely, but they do produce a potentially very harmful amount of small particle dust.
Depending on the state of the bone, the speed and coarseness of the machine being used etc bone dust varies in size from about 3-300 microns (µm).
The larger of these particles (>100µm) are not too troublesome as they tend to settle from the air relatively quick and are not so easy to lift again simply by moving. They are still not great and you don’t want to be breathing through a cloud of it, they are simply not as bad as the smaller particles.
The particles that are <100µm are a different matter though. These are what is considered to be “inhalable dust” (can be inhaled through the nose and mouth during normal breathing) and can be dangerous. Once the particle size gets down to <10µm it is known as “thoracic dust” (can pass through the bodies various defences and enter the lungs), and given that bone dust does not naturally live in your lungs it can be safely assumed this is not a good thing.
Even worse than thoracic dust is the “respirable dust” (particle size of less than 5µm) as these particles can even penetrate into the gas exchange areas of the lungs and potentially cause all kinds of trouble.
Beyond the obvious method of prevention (don’t use powered grinders/sanders), there are a couple of methods of keeping inhaled dust to an absolute minimum.
The easiest is sorting out some decent PPE. There are many different grades of face mask on the market and even the most basic of these is better than nothing. However, if you are going to engage in frequent or heavy dust producing operations, it is better to get something more serious. In striving for a balance between saving money and, well, not dying of bone filled lungs, the best option for most people would probably be a FFP3 (European) or N100 (US) rated mask. A single disposable FFP3 mask is about £3-4. If money is no object, or you will be working daily with lots of bone dust, some kind of all enclosing filter mask would be much better. Other kinds of filters such as charcoal, HEPA and so on are not necessary as they focus on vapour, exceptional small (<1µm) particles or pathogens. Regardless of the kind of mask you use it is always important to remember to ensure it fits your face correctly – it is no good having a mask that filters out everything if you leave a huge gap around the side of it.
In addition to personal protection, a workshop extractor or filter system can be a good idea. Again this can range from a simply vacuum attachment on a tool that sucks away dust to an extremely complex all room filter and purifier. Again, for non-frequent or heavy dust production, the former is the best option. Just have a cheap dust extractor or hoover that can be attached individually to tools as needed. Mounted tools that don’t have a built in connector (such as bench grinders) can be housed in a custom box that has the hose fitted to it so that the air around the machine is constantly removed.
The combination of removing dust as it is created and then a second layer guarding when you inhale will cut down on over 99% of the material you could breath in (and that’s not a made up stat, the FFP3/N100 filters have to be even more efficient than that to meet standards).
Keeping dust free
So the three simple steps to saving your lungs when bone working are;
- Keep powered sanding to a minimum
- Try to extract as much dust as possible at the source.
- Wear a good dust mask.
Further information on the human respiratory system can be found here if you wish to know more about how it works and why proper safety measures are important.