Did you ever try scoring both sides of the cut with the knife before you break it? I started doing that on my last remodel and it made a huge difference. No more torn paper or chipped mud, just a clean snap right along the line. Also switched to a carbide blade that stays sharp way longer than the regular ones.

8 years and still waiting, that stump's just flexing on you at this point.

Wait, @victor779, did you change your whole approach after one bad pour critique or did you actually flood someone's basement? I guess if the guy had a point about water content, it's easier to adjust than to explain to the foreman why your slab is turning into soup. Either way, sounds like you took the high road, which is more than I can say for the dude screaming about his wet concrete.

Saw a video from an old timer who breaks down knives for a living, and he said 90% of the damage he sees comes from people dragging the blade backward on the steel. That stuck with me because I used to do it myself until I messed up a good Wusthof. The Sharpie trick is the only reason I finally got my angle right, but honestly, nail polish sounds smarter since it stays on longer. Maybe the real problem is nobody shows beginners how to hold the steel steady first, so they rush and screw up the motion.

Oh man, that's rough. Losing a whole panel to a half inch template error hurts, especially with how expensive materials are right now. We've all been there with measurements going sideways, but it still stings every time.