My dad worked at Boeing and related companies for decades. Lots of manufacturing steps had odd things that had zero documentation. Lot of protectionism for j

My dad worked at Boeing and related companies for decades. Lots of manufacturing steps had odd things that had zero documentation. Lot of protectionism for job security. Others just laziness. One he mentioned was using fishing line to help foam set correctly. When replacements tried to build the part it just wouldn’t work right. They had no idea why.