Ecodefense: A Field Guide to Monkeywrenching 1993 [x]
Tree spiking has forced the development of a number of countermeasures, the most significant being the use of metal detectors to locate metallic spikes embedded in tree trunks. Many sawmills routinely screen all fallen logs at the mill to remove commonplace metallic objects like nails and old barbed wire. There is an increasing likelihood that conventional metal spikes will be detected before reaching their intended target ā the costly sawmill blade.
Ongoing research has produced several non-metallic spikes, or pins, that promise to defeat the metal detector and wreak havoc inside the sawmill. The first of these is a high-fired ceramic pin made of the same type of stoneware used by potters who hand-throw (on a potterās wheel) cups, bowls, plates, etc. Clay bodies can be stiffened and made even more durable by the addition of āgrog,ā a gritty, sand-like material usually made of a high-fired refractory material (ground stoneware) or simply a pure quartz sand. High temperature firing brings about chemical changes in the clay, causing the particles to bond together through vitrification. The end product is a material so hard it will easily scratch glass. In hardness, it ranks with some types of steel, although it will shatter under a heavy blow (making it unsuitable for spiking with hammers). Still, it is high enough on Mohsā scale of hardness to cause damage to sawmill blades.












