Obviously I never intended to save the bolt - just to get it out. Not just because of strength, but also because of the shape of the head after trying to get it out before!
No - it would not shatter (no room for it to - it would shrink, just as it did). But I do recommend that the coolant be aimed directly at the bolt, and not hit the rest of the block!
By the way, being a pilot myself, I have never seen a prop held in place by aluminum bolts! (I'm not kidding - there is a fictional joke out there about a prop having been attached with fitting bolts from a bicycle shop, and the prop deciding to do a solo away from the airplane at altitude!)
1989 560 SEL (black/black)
2001 Audi TT Roadster (silver/grey)