A stick bomb is a (mechanical) spring-loaded device constructed out of flat sticks woven together under tension. Other names for stick bombs include Chinese stick puzzles, xyloexplosives, and frame bombs.
Simple stick bombs made out of four, five, or six sticks have been known to schoolchildren for ages. They were often known as "Chinese stick puzzles" which indicates a possible origin for the devices. Tarnai (1989) describes several designs, including those with indefinite size which he credits to Ruina. Ruina claims to have invented the "infinite popsicle-stick bomb" in 1971 although there is no evidence that others did not invent this idea earlier.
Stick bombs can be constructed out of most flat sticks of the appropriate dimensions. The usual material for construction is wood, but plastic can also be used. Ice pop sticks (craft sticks) and tongue depressors are popular because of availability, low cost, and because they are easily coloured. Tongue depressor sticks are strongly recommended for construction as they have lower tension than craft sticks and thus are easier to work with.
The sticks are woven together to form a reticulated grid with each stick held in place by tension created by the elasticity of wood or other material. If constructed properly, the removal of a single stick causes the other sticks to fly apart with surprising force. The speed of the shock wave depends on the materials used. If craft sticks are used, the detonation speed is approximately 30–40 meters per second (67–90 miles per hour); for tongue depressors, the speed is under 10 meters per second (22 miles per hour). Stick bombs, especially those made from craft sticks, can spontaneously explode without warning from a weak stick or from warping. For that reason, it is important to wear safety goggles when constructing stick bombs.
The variety of configurations in which stick bombs can be constructed is virtually limitless, and there are several tricks (stunts) that can be incorporated into the design. However, it does not always work if the sticks are thin, crooked, or deformed in any way. For reasons of structural stability, each stick is touching at least three other sticks in a frame bomb.
- See, for instance, POP! POP! POP! Ultra Fast Stick Bomb "Xyloexplosive", by Rachel Mansur, 27 Feb. 2010, accessed 11 May 2012; Videos of Kinetic Art Gadgets, by Tim Fort, accessed 11 May 2012; or Xyloexplosives 1001: Introduction to Large Stick Bombs, by Tim Fort, posted on the Internet Archive, accessed 11 May 2012.
- Tarnai, Tibor (1989), "Duality between plane trusses and grillages", International Journal of Solids and Structures 25 (12): 1395–1409, doi:10.1016/0020-7683(89)90108-X