Safety

WARNING 

Instructional articles or video tutorials found here or elsewhere may not give you all of the information needed to accomplish a given task successfully or safely.  Do your research, learn, and observe safety precautions when experimenting in areas unfamiliar to you. Learn more than you think you need to know.  Information is at your fingertips, and you must be responsible for your own safety and for the safety of those around you.

Just Because You Saw it on the Internet Doesn’t Mean It’s Safe to Try

Although most of the articles on this site are intended to be narratives rather than tutorials, there will be times when potentially dangerous processes are described in detail such that you may be tempted to try them on your own. It should be understood that wood & metalworking tools and machines, chemicals, electricity, dust, sharp and pointy things, wound-up things, molten things, combustible things, and actually all things are fraught with hazard and have the potential to render you sightless, limbless, or lifeless.  The trick is to not only learn what you need to accomplish the task of interest, but to think outside of that narrow mission and understand the potential hazards that may appear along the way.

You only need to watch a few videos on YouTube or hang out in an experimenter or DIY forum for a period of time to realize that some individuals will dive into activities virtually unaware of potential hazards.  Tutorials tend to show how to perform a specific task in an orderly, nominal manner and are not usually (I say not usually) hosted by someone performing the task for the first time – you don’t see the blunders or mistakes that you may run into on your own first attempt.  All too often reading some of the comments and questions following a tutorial gives a disturbing look at how easy it is to get in over your head.

Even with an extremely conscientious and cautious approach to most anything new and potentially hazardous that I ever tried, I can look back and remember more than a few instances where something totally unexpected came out of nowhere and could have injured or killed me.  A potentially lethal electrical shock through several feet of “insulating” glass, a burst mold filled with 2100 degree molten metal, inadvertent exposure to asbestos, radium, and beryllium oxide dust, a large tree trunk falling just behind my lawn tractor  – hazards come out of nowhere, even if you do your best to anticipate them.

Without rehashing the hundred safety warnings that accompany your new toaster, here are just a few random topics that I have had reason to ponder recently either from reading forums (fora?) or from personal experience:

• Don’t wear rings around high current sources (welding, resistance soldering, high flux AC magnetic fields).  A current passing through or induced in the ring can cause burns.  Gloves are acceptable for protecting against contact currents, but it is safer to take the ring off just in case.  Rings can also represent a grabbing hazard around rotating machinery.

• The use of woodworking and metalworking machine guards is advised where possible, but let’s be realistic about it.  There will be times when the use of a guard is impossible or would only increase the risk due to lack of visibility.  In these cases keep your eyes protected, stay out of the trajectory of flying cutter parts, and use push sticks or custom-made holding jigs to keep your body parts away from hazards.  Push or pull only in directions that will allow you to fall clear of hazards should you slip.  I’ll spend any amount of time that it takes to make a safe holding jig for a difficult cut, even if it’s just a single quick pass, and I almost never rip without a blade guard and anti-kickback kerf-splitter in place.

• Speaking of flying cutters, avoid lingering in the plane of saw blades (carbide teeth can fly off) or router bits.  Bandsaws can seem pretty benign and that appearance may encourage you to allow your fingers near the blade, but it pays to anticipate blade breakage.  A broken blade may stop safely in its tracks, or the inertia may cause it to shoot out of the upper guide and into your fingers.

• If you use sanders, bandsaws, or any other dust-creating machines for both wood and metal, think about what can happen when sparks splash on the fine sawdust/aluminum powder mix inside the machine and are fanned by the airflow from spinning parts or your dust collection system.  The hazard can smolder, so to speak, for some time after you have left the shop. Keep separate machines for metal and wood or keep them clean.

• Electrical current passing through certain parts of your body kill you. Voltage is the enabler, but the current does the deed.  High voltages make it easier to pass lethal currents through your body, but lower voltages can also result in lethal currents if the contact resistance to your body is low.  Line voltage can be deadly and should be treated with the utmost respect. When working on electrical devices you should consider the ground you are standing on to be a potential current return path, so the adage of keeping one hand in your pocket will not suffice unless your device is powered through an isolation transformer. Keep devices unplugged when possible while working inside, otherwise use insulated tools.

  High voltages don’t need to be contacted through wires or traditional conductors.  Air or partial vacuums within glassware can ionize and put you in a current path when you might think you are a safe distance away.  Insulation breakdowns within a high voltage transformer may change an isolated winding to one that is tied at some point to ground intermittently, possibly increasing shock hazard.

• Buffers with large wheels or powerful motors can be incredibly hazardous, and learning to hold a piece at just the right angle of attack against the wheel can only be learned through experience – sometimes bad experience.  Even if the buffer motor is not very powerful, enough kinetic energy can be stored in a large cloth wheel spinning at high rpm to grab a piece from your hands in an instant, sometimes taking your hand with it.  When polishing small items it is advisable to find a way to mount them to larger fixtures that are safer to hold.  Metal frames or flat items with cutouts can be particularly dangerous to hold while polishing; the wheel can grab the cutout.  Attach flat items to a board to prevent the wheel from entering and grabbing the cutout.  Use screws if the item has holes or small hold-down blocks if it doesn’t.

• Working with molten metal presents multiple hazards. Avoiding direct contact is obvious, but the warnings to be wary of moisture should not be taken lightly.  A drop of water falling from the sky onto a molten surface will vaporize without a problem, but that drop of water or even a large snowflake trapped under or within molten metal will cause a mini-explosion.  The tops of molds should be kept dry, and tools that come in contact with metal must be preheated until known to be very hot.  A cold tool placed over a furnace exhaust in an effort to preheat it will form condensation first, so adequate time must be allowed to boil that condensation away.

• Extended exposures to many substances such as epoxy and superglue (CA) can develop allergies over time, even when there were no ill effects observed initially.  Epoxy can cause various types of direct-contact skin dermatitis, and even the odor can trigger reactions.  Methyl 2-Cyanoacrylate (in superglue) can trigger severe flu-like symptoms including runny eyes and nose and chest constriction.  The use of odorless CA may be acceptable if use of regular CA is not possible.

• The hazards of pressure and vacuum should must be understood when designing or working with pressure/vacuum vessels.  A container evacuated internally will be subjected to nearly 15 pounds per square inch (psi) of atmospheric pressure on the outside.  This may not seem like a problem until you start adding up the surface areas – the glass face of an old 32″ TV picture tube is supporting something like nearly 8000 lbs – four tons of atmospheric pressure.

  Containing high pressure can be even worse. Where a total vacuum will subject one side of a container to approximately 15 PSI at worst case, a pressure vessel has no fundamental limit.  Any pressure vessel must have a relief valve to act as a fuse to limit the maximum pressure, and the maximum safe pressure for a homemade vessel is not something that can be intuitively estimated.

  One of the forums has had an ongoing thread discussing the topic of making your own large chambers for vacuum and pressure resin casting.  There is one participant that is absolutely convinced that vacuum is much more dangerous than pressure (based on his experience with gas tanks!) and is working on a large pressure tank made from an old water tank.  While the tank may be able to hold water pressure, once it is cut to create a tank and lid, considerable thought needs to be put into using heavy flanges for reinforcement and a lot of clamping at the seal.  From what I have read thus far, I would not want to be anywhere near that tank when pressurized.

There are simply too many hazards in the workshop and in life to list.  If you experiment, explore, and make things, or even if you text while walking down the street, you will be exposed to hazards.  Anticipate them and avoid your Final Destination moments.