Crappy steel and welds failure case

One-line aside on his consulting business.

If you're talking about a ceramic — I had some guys in the office from a company last week, and they're trying to make better ball bearings for jet engines. They want to make them out of silicon nitride because it's one of the toughest ceramics. The size flaws they've got to be looking for are five microns, because five microns will be a critical flaw size in fracture mechanics for a ceramic. For a metal, maybe half an inch, two inches is a critical flaw size. You can have some pretty crappy welds in a metal and it still is not going to fail. Although if you have a crappy steel and crappy welds, it will. That's helped put my kids through college, okay.