Official Luthiers Forum!

I've got a guitar that came in with a lifted bridge (a lot of those lately...) Anyway I've noticed a really tight crack that runs towards the end pin from behind the G string hole. The crack didn't move much when I pushed on it, and underneath I noticed no loose braces, all clean and tidy looking glue joints. I was able to pump some glue into the crack and feel confident that it is sealed up. I will usually add a cleat or two to a crack like this but in this case on one end the crack stops at the G string hole, and travels about 5" towards the end pin where it stops under a brace. In between the two endpoints I have another brace and the bridge plate. There's really only about an inch of real estate in between those two braces, and not much space between the bridge plate and the middle brace. Not much room to cleat. Am I wrong to assume that the crack has likely travelled as far as it will and the interior architecture of the top has effectively already cleated this crack? Should I put a cleat on the other side of the outside brace in case the crack does decide to move further?

Cleat it, the edge gluing of crack repair is mouse nuts in terms of gluing/surface area. It's often hard to get enough glue in a crack so that you see little tiny beads of glue the entire length of the crack on the inside.

My cleats are spruce (for spruce tops) slightly more than 1/2" long and less wide and around .060" thick. I bevel all edges to nothing and of course install across the crack with the cleat grain at 90 degrees to the crack direction.

We can't know how much glue is under a brace where it traverses a crack so I use cleats if there is any span there, say an inch or more between braces, tail blocks, bridge plates etc. Minimalistic cleats won't even weigh a gram so don't be afraid to use them.

I don't see any need to cleat for the anticipated travel direction of a well repaired and cleated crack.

Be sure to advise the client in writing that their guitar was dry and it will crack again if they continue to be a dotard and don't humidify it. . I write it on the bill and show it to them when they are picking up. Crack shaming if you will.....

BTW several years ago I developed a hernia on the right side of my abdomen.... I got it fixed surgically and they cleated me... with mesh.... Several years later I have now developed two more hernias now on the other side and in the middle.... Guess I need to drink more and increase my RH....

Anyway it's been our experience that some guitars are more prone to cracking than others and some clients are more prone to abusing their instruments than others. Cleats are cheap insurance that when your client has to visit you again it will be for new, billable work and not to redo a prior, failed repair that should and could have been cleated.

Haha, thanks Hesh. On with the cleating.

I'm always suspect of cracks that transverse or even stop at braces. Check it real good with a bright light. When you have cracks in an aluminum airplane wing you find the very end of the crack and drill a hole in it... Seriously. The idea being that a sphere is one of the most stable conditions almost anything can be in and as such the stress is relieved and the crack will go no further. I'm not saying you should drill holes in the top of your guitar But your idea of cleating the end of the crack on the other side of the brace has merit imho. I would probably just double and triple check the brace and glue it tight if it needs it.