I bought a replacement HSI (IG101) recently, and my parts guy carefully inspected the new part before selling it to me, stating that he wanted to make sure it wasn't already cracked. I appreciated that.

Now, my question: When I removed my failed ignitor, just for fun, I wanted to see how brittle these things really are. Turns out I could flex it quite a bit before it broke (its a spiral type.) Are these things most sensitive during the manufacturing process, or when they've cooled down after manufacturing, or after they've had some wear and tear on them, or are they sensitive only while they're energized? Despite having thousands of cycles on it, the old one sure seemed tough (but it obviously had developed a hot spot on it.)

Just curious.