It normally entails taking a piece of metal, usually scrap, and applying it to a grinding wheel in order to observe the sparks emitted.
[4] Automated spark testing has been developed to remove the reliance upon operator skill and experience, thereby increasing reliability.
It has been found that this system can determine the difference between two materials that give off sparks that are indistinguishable to the human eye.
[2] In 1909,[8] Max Bermann, an engineer in Budapest, was the first to discover that spark testing can be used reliably to classify ferrous material.
He originally claimed to be able to distinguish different types of ferrous materials based on percent carbon and principal alloying elements.
[12] In the early 21st century the availability of portable X-ray fluorescence equipment largely superseded it in laboratory practice.