November 30, 2017
As I write this column, home heating units are working hard. When I walk across the carpet and touch something I get a "zap." It's static electricity. The Shooting Times staff have received questions lately about static electricity and reloading safety. The questions tend to have two parts: Is it dangerous in a reloading setting and how to deal with it.
"Static" means "not moving." Static electricity consists of stationary charges that build up on one surface, creating an imbalance of charged particles between objects — an unstable condition in nature. This imbalance remains until equalization returns through grounding or an electrostatic discharge, such as a spark. Static electricity has very high voltage but very low current (amperage). A discharge in air forms a high-voltage, low-amperage spark in the vicinity of "energetic materials." The spark heats the air around it to temperatures that can ignite volatile materials. Static electricity's hazard to reloading is largely limited to primers and propellants.
Primers and primer residue are, in my experience, the most sensitive to static electricity. Conditions must be just so, but I have investigated static-triggered primer accidents that were far from trivial.
Fortunately, the modern percussion primer and its packaging are so evolved that it takes a lot of abuse to create a problem. The foil paper and lacquer-type sealants offer a lot of protection against static. The big hazard is primer dust.
Most materials are easier to ignite if ground to dust-size particles. In February 2008, an explosion in a Georgia sugar processing facility killed 14 and injured 40 of the roughly 112 souls on site at the time. Some ignition source found its way into an environment where sugar dust hung in the air. Most of us would not consider sugar a "hazardous material," yet lives were lost and the facility was largely turned to rubble.
Under prolonged and vigorous vibration, bits of the primer pellet itself may break loose and build up in the package that holds the primers, in primer trays, in primer tubes for automated loaders, and around the primer feed mechanism of your loader. Primer manufacturers have stringent test protocols for evaluating a production lot of primers for its potential to create dust. The dusting test represents greater abuse than most reloaders can imagine. With today's primers the amount of dust is incredibly tiny, but if dust accumulates in your equipment when using primers, your housekeeping and materials handling need serious and immediate review.
It is not hard to minimize this problem. Maintaining a clean reloading area and gear is the most effective step. Never store or transport primers in feed tubes; move leftover primers from the tubes to their original packaging at the end of a loading session. Look through tubes after about every 1,000 primers are seated to see if dust is building up. If they need cleaning, do it while holding the tubes under water. The long pipe cleaners sold by florists supply and craft stores are cheap and effective tube brushes. Never oil primer tubes as that can accelerate dust buildup.
Dust can accumulate around automated primer feed systems. I use a pastry brush with a wood handle and natural — not synthetic — bristles to clean around feed mechanisms. Use a degreaser if needed to remove dust-attracting oil. If the mechanism needs lubrication, use a dry lube like graphite or ask the equipment manufacturer for maintenance advice.
Smokeless propellant has a relatively high kindling temperature, so it's harder to ignite big granules in the presence of static, reducing but not eliminating the hazard. Blackpowder is easier to ignite and easier to crumble, so it's a bigger worry. However, both products are elevated to the Red Zone if reduced to dust. What if you spill propellant on a hard floor and opt to walk in it for weeks instead of cleaning the mess now? You've just made dust that is quite easily ignited by many energy sources.
How to Reduce Static Risk
There are a number of things you can do to make an overall reduction in static risk in your handloading area. First, dry climates increase the frequency of static electricity events, and heating systems can dry out the inside air in winter. Moving air itself can create static. If your house has forced-air heating, you can block the loading room vents with cardboard or foam and use a convection-type heater to maintain comfort. You should also consider purchasing a free-standing room humidifier for your load area.
If your loading area floor is carpeted, there are reasons to remove it in addition to carpet's amazing ability to create a massive static charge. Spilled propellant and even dropped live primers can hide in carpet, as can lead residues. My preference for a loading room floor is natural wood, assuming the installation does not leave gaps that can collect propellant. My second choice is bare concrete without gaps or expansion joints.
Likewise, I prefer a benchtop made of tight-grained wood. If you need more than one piece of lumber for the top of your reloading bench, make sure the glued edges are finely jointed for a tight fit that won't collect residue.
Some benchtops are finished with synthetic countertop material that can encourage a static charge. Wiping synthetic surfaces with a dry cloth can make it worse. Always use a damp cloth for cleanups. If you can't replace your benchtop, there is a way to greatly reduce its propensity to create a nasty spark, and it's likely that you already have the solution. Look in your laundry room. Dryer sheets used to reduce static cling in clothes run through a dryer are excellent for minimizing static charge. Use a fresh sheet to wipe synthetic benchtops and other plastic surfaces. They also reduce static charges with plastic scale pans, funnels, and powder measure hoppers.
In severe static electricity conditions or those in an OSHA-covered workplace, extreme measures may be required. Static electricity needs to be dissipated to the earth, but any grounding system should be designed and installed only by qualified engineers and electricians.
For the average reloader, common sense, alertness, and cleanliness go far toward a safer hobby.