top failing at glue seam

[Danny]

while thickness sanding with my r.o. sander my top split at the glue seam. i had previously repaired this same split with ca b4 profiling and installing rosette. Should i give up on? i do have another top that i can use. i was quite rough with while sanding it. Maybe i was too rough while tapping it and shaking it trying to figure out what everyone else is talking about in knowing when to stop thinning it. btw, this is my first.

[tippie53]

tell us your gluing procedure , what glue clamping etc. Also how did you join the top

[Danny]

The top is a martin reject. I did not notice the crack when i first receved the top. I first noticed the crack around July and i seeped ca glue into it and held it until it set up. My little fix seemed to work fine and top held up to my shops typical wild humidity swing, from 67% in summer to 35% current. It held up to profiling and rosette inlay. while thickness sanding and my subsequent tapping and shaking to listen for any type of tone or ringing (i'm just learning!) the top failed at that seam again. just a few inches right at the tail block area. I actually reglued it but it failed again yesterday....just an inch. I realize that my reglue efforts are likely not getting good wood contact and i may be just gluing glue together instead of wood. I am wondering if 1. Can you be too rough with these unbraced tops and 2. Is the proper fix going to be too time consuming or advanced for me and if so i should just move on to working on my other top?

[Danny]

Oh, i just noticed i did not answer one of your questions....i did not glue that top up, presumably someone at the Martin factory did. It may have been rejected bc of the crack. I just did not notice the crack for several months after i received it or perhaps the joint failed after i received it. I have stored it flat with stickers and weight on it to keep it flat.

[tippie53]

I don't like CA and spruce , it has a tendency to turn yellow over time. Also the chance are the glue joint may have been stressed. I would start anew

[Danny]

Thanks guys. That's a bummer but i figured that was the answer. And yes, i have been really itching to get to work on gluing the bracing while my humidity is so low. I trying to find the time to start a project blog on this forum but I have not yet found the time.

Thanks,
Danny