Gray Matter: An Elemental Recipe For Creating Great Showers of Sparks

Hot Shower When a grinder is applied to mischmetal—a combination of various elements—it produces copious quantities of big sparks. Mike Walker

Metals can be classified by hardness, malleability and conductivity. One quality you won’t find listed in the reference books is sparkiness.

A delicate balance between flammability and hardness determines which metals spark. For example, magnesium is a famously flammable metal, but grinding it produces no sparks because the energy needed to cut chips from the soft metal is not enough to heat them to their ignition point.

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DIY, Gray Matter, Theodore Gray, flammability, gray matter, lathanides, mischmetal, November 2009, sparks

Lighter “flints” aren’t made of flint but rather a mix of lanthanides, with iron added to tame the excessive sparkiness of the other elements. Lose the iron, and you have the pinnacle of sparkiness: Mischmetal (German for “mixed metal”) contains lanthanum and cerium, with smaller amounts of other lanthanides. Blocks of it are often used in movie special effects. For example, a scene in which a car blows a tire and drags on its rims needs a stream of sparks coming off the wheel, so a block of mischmetal is strapped on for spectacular effect.

Ironically, modern aluminum wheels are nonsparking, so the only place this still happens at all is Hollywood.

Tailgaters Beware: The author tows a block of mischmetal along the road, turning his minivan into a fire-shooting menace.  Mike Walker