Our monthly column in Sport Aviation/Experimenter Magazine for the month of November was an article on spark testing steels.We discuss methods which you can use to identify a piece of 4130 chrome Molly steel from a piece of mild steel or any other type of metal for that matter.
If you're not a member of EAA "you should be".The magazine alone is well worth the annual membership fee.
Spark TestingAs with most building trades, (electricians, masons, carpenters,) there are time proven materials and a base line method of performing tasks which become “standard practice”. As an aircraft builder, you soon learn that there is also a time proven set of practices and building materials that are commonplace within the aviation community.
If there is one universal commonality among the countless aircraft types, it is the use of steel within the structure in some form or another. From the very earliest of aircraft to even the most current, exotic composite aircraft, there is still steel in some form or another used within the aircraft.
The FAA Aircraft Maintenance Technicians Handbook (FAA-8083-30), Chapter 05, has a great explanation of all of the different types of steels, their chemical composition, their characteristics, and usage.