My friend send me a photo of a cracked part that he JB Welded.
He used an allen key as a splint! How smart! It's funny, if that happened to me, it would not have occurred to me to take the splint approach. I would have tried to keep it clean/seamless, and only applied JB to the inner surface of the break seam (to just end up with a clean hairline crack)
As you know, this never seems strong enough, and often breaks again. Plus, it's annoying to hold it in place while it dries. His approach was just to glob the JB over the entire break, which almost serves as a "cast"....which diffuses pressure to a larger surface area than just the crack seam.
He agreed, and said he first tried it without the splint, but it broke again when I tried to reassemble it. There was no way the epoxy alone would hold the broken pieces together under stress. That's when he decided to use the splint and glob as much JB on there as possible.