Martin tailblock and finish repair

[AcousticAmber]

Hey everyone

Once again I'm seeking some expert advice on a Martin repair I'm doing (I bought it damaged to repair and keep).

Its a brand new GPCPA4 which (I'm guessing) was dropped on the endpin pickup resulting in a cracked tailblock, finish cracks on the top, loose binding and a separated top.





I have repaired the loose top and binding and the tailblock crack so everything is flush and stable now, but not sure exactly how to tackle the finish cracks in the top.










I know that if I fill with thin CA and sand, it won't be an invisible repair... If I spray the whole area with nitro will that be enough to fill the cracks? Or should I use a different type of finish? Or a different method?

Advice appreciated, thanks in advance

[mirwa]

Leave it alone and just play it, anything from here is likely going to involve refinishing the whole top and sides to hide it

Steve

[Howard Klepper]

I would not be at all concerned with the cracks in the finish. You are more likely to make them worse than to fix them. It's never going to be a new guitar again.

But I would be concerned about the likelihood that there are torn fibers in a line running cross grain at the edge of the tailblock, where it flexed the top upon impact. You might want to get an L shaped or triangular block in there, glued to both tailblock and top. It should be feathered down to nearly nothing along its outside edges.

[B. Howard]

Not sure what Martin is using on those these days for finish.... If it is USA made it may be their nitro variant and it could be re-flowed with some retarder, and a light build coat added over the area then sanded and buffed.

If it was made in Mexico it is likely a conversion varnish of some type and the only way to repair would be at least a partial re-finish of the top.

[M Hayden]

Originally Posted by Howard Klepper

I would not be at all concerned with the cracks in the finish. You are more likely to make them worse than to fix them. It's never going to be a new guitar again.

But I would be concerned about the likelihood that there are torn fibers in a line running cross grain at the edge of the tailblock, where it flexed the top upon impact. You might want to get an L shaped or triangular block in there, glued to both tailblock and top. It should be feathered down to nearly nothing along its outside edges.

^ This. With the size of the hole for mounting electronics, it should be relatively easy to fit a piece to support the top as Howard says, and it adds a safety margin if the top is indeed partially compromised at the edge of the tailblock.