Fret Board Top Crack Repair

Cracking of the top along the fret board is pretty common on acoustic guitars. Seems to me this is more likely with poor upper bout bracing. But I digress.

Pictured here are two images showing how to clamp the neck block pulling the top back into alignment.

Preparation requires removing the neck and the back, followed by completely removing all bracing between sound hole and neck block. This includes all traces of neck block extension glued to the top between sound hole and neck block. (Not referring to the fret board extension which has frets installed.) You must remove all glue residue. So, yeah, there is potentially a lot of work involved with this repair. In the case of guitars with only a block glued the top between neck block and sound hole, this repair will prevent all future tendency for the neck to rotate into the sound hole. So this is an improvement over the original design in many cases.

This image shows the key to the clamping strategy. The 1/8-inch thick strip of spruce sticking up to the left forces the top under the fret board to pull back into alignment. As the large deep throat clamp is tightened, the top area previously under the fret board extension is pulled back. You may need a thicker strip.

The image shows a different angle of the clamping setup.

After pulling the top pieces into alignment, you should glue a cross brace just above the sound hole. Then, glue a piece of top scrap almost the full width of the top. This piece should cover 100% of the distance between the neck block and the neck side of the cross brace. You can see I seriously pressed the cross brace and the top scrap into place. I wanted that top to be dead flat. You can see the top scrap colored orange on the right. I used a scrap from a J-45 that I re-topped.

Martin Guitar Company fixed this problem long ago with the pop-cycle brace. Kudos to them.