In the Picture-of-the-Day for February 14, 2017, I told the story of Harvey Reid’s Chrysalis mandocello.  This is a much better picture than the one used then, so I thought I should put it up here.  Also, it is un-retouched. This body was originally used as a guitar, and when it was fitted out with mandocello parts, the much higher stress of the eight heavy strings caused a stress crack to open up in the back of the frame right next to Harvey’s thumb. I disappeared the crack in the Feb 14 write-up’s picture but admitted it plainly. Here is a much better raw picture including the crack.

Carbon fiber is very tough stuff. It will bend, but you have to be extremely dedicated to break it, and will likely end up red-faced and out of breath from the effort. Here the black epoxy matrix molded around the carbon fiber perimeter strips has cracked, but the carbon-fiber spine within is just fine, as is the continuous fiber grillwork, which is screwed onto the frame at thirteen hard points every 50mm around the outer perimeter of the frame.  This scheme distributes the string stress around the frame such that any given hard point handles only about 5% of the overall string tension. Even if several hard points failed, their load would be picked up by the others, and the overall structure would remain stable.