I had an APC 12x6 explode on my test stand. The prop had previously been mounted on a plane, but due to a prop strike on landing it shed the tip on one blade. I just cut it down to an 11x6 and only used it to run on engines on the stand. I was running an SC .52 at WOT, when it went bang a piece 2 1/2x5/8" pierced my shed wall (metal shed). I have my stand bolted to a black&decker work bench, the force and sudden imbalance almost topled the work bench. Now I only need to see 1 tiny dink in a prop and it goes in the bin.
Once bitten twice shy ...