For arborists, loggers, and utility line clearance crews, chainsaw protective chaps are the absolute last line of defense between a running saw and their femoral artery. These chaps do not stop the chain with thick armor; they work on a brilliant, passive principle called "clogging." The front panels of the chaps are stuffed with hundreds of feet of loose, ballistic Kevlar or Dyneema threads. When a spinning chainsaw chain accidentally strikes the chap, the chain's teeth instantly hook into the loose fibers, pulling them out and jamming them into the sprocket and chain drive, stalling the motor before the chain can reach the flesh.
But this intricate, life-saving web of ballistic fibers is incredibly fragile, and workers are destroying their chaps without even realizing it. The two biggest killers of Kevlar chaps are ultraviolet light and the commercial washing machine.
Kevlar is highly susceptible to UV degradation. Loggers routinely leave their chaps draped over the brush guard of the skidder or hanging in the back of the truck in the blazing sun. The UV rays break down the molecular bonds of the Kevlar fibers, making them brittle and weak. If a chainsaw hits a UV-degraded chap, the brittle fibers simply snap instead of being drawn out, and the chain cuts right through to the bone.
Even worse is the laundry. Chainsaw chaps get soaked in sweat, bar oil, and sawdust, making them disgusting. Workers throw them into a washing machine with heavy detergent and hot water, or worse, pressure wash them. The violent agitation of a washing machine pulls the precisely layered Kevlar fibers out of their batting, bunching them all into the bottom of the leg panel, leaving the top of the thigh completely unprotected. Furthermore, the harsh detergents strip the natural oils from the Kevlar, reducing its tensile strength, and the hot water shrinks the ballistic material, permanently ruining the protective layup.
To clean chaps, you must remove the ballistic pads (if they are removable) and hand-wash the outer shell in cold water with mild soap. If the pads are sewn in, you must hose them down with cold water and gently brush the sawdust off. Never use high pressure, never use hot water, and never use detergent on the pads. Store chaps in a dark, dry closet, not in the sun. If you hold a chap up to the light and see that the internal fibers have bunched up, or if the material feels stiff and brittle, the chap is a false sense of security and must be thrown away before it costs you a limb.
