Magnesium - Myths-vs-Facts
"Few of us will ever forget the time-honored magnesium strip experiment. It has left many with the idea that magnesium of any kind ignites readily and burns quickly. The truth behind this impression is a bit more complicated. It points out facts we never learned in high school . . .
Myth: All magnesium ignites easily and, once ignited, is difficult to extinguish.
Fact: It is true that magnesium (Mg) can be ignited. Once ignited, the fire can be sustained in air under the right conditions. This is about the only principle ever demonstrated by the chemistry professor. (Erickson's high school teacher even put the strip into a bottle of oxygen to enhance burning.)
When a strip of Mg is very thin, you can supply enough heat to ignite it with the flame from a Bunsen burner. Even then, to get it to burn, you have to tip the strip downward to heat the area above it. That puts more of the heat of the flame into the metal.
When a bigger piece of Mg. . . is put in a high-temperature environment (an oven or a burning car), it's possible to get it up to a temperature where it will ignite and burn. Even then, it is usually the last thing to burn. Investigators have looked at old VW Beetles, which had about 60 lb of Mg in them. In a car fire, the entire car is consumed before the Mg will ignite."
As I stated above, B-52 brake calipers (all eight of them) are made from magnesium, in the last 72 years, how many B-52s have made overweight landings resulting in hot brakes? (Rotors can reach temperatures well over 1500° F.) We have lost as many B-52s to brake fires, as we have to F-100 Super Sabers shooting them with an air-to-air missile., And, in that one brake fire incident, it was due to a hydraulic line breaking and the hydraulic fluid catching on fire, not any of the magnesium components.
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