More guitar fix it trivia here.
An open crack down the middle of an acoustic guitar top means the guitar is crying out for more humidity. This article suggests one way to fix the problem. This method works only with the back off and the braces removed because the humidifiers must lay right on the top wood.
This is yet another good reason to do brace conversion on Harmony guitars. Back removal lets us repair all kinds of problems.
The image below shows the smallest "GLAD" brand storage container made. Note the top drilled with 8-10 1/4" holes. Inside there is a chunk of cellulose sponge wetted but not dripping with warm water. You don’t want any water dripping out of the cup.
The image below shows the cups inverted on the top. I place these wherever there is a crack. The top wood absorbs the moister and gradually closes up in a day or two.
If you look closely you can see the crack is already closed. Yea!
Don’t leave these on for more than a day or two. You might warp the top.
Remember to align and reglue the crack.
©2020 D.R. Hanna