Pickguard cupping on an 81' Guild F30

[eliya]

Hi everyone!

The top of my Guild F30 is cupped where the pickguard is, along with a small crack near the fingerboard extension. To me this seems like the classic pickguard shrinkage and cupping, and Frank has two, very thorough guides to fixing this problem (this one and that one). However, I want to make sure that this is in fact pickguard shrinkage and that the prying and re-gluing of the pickguard with water-based glue is the right fix. I'm attaching pictures of what it looks like.

The first picture shows the cupping halfway across the length of the pickguard, and you can see that the cupping starts almost from the edge of the top. The second picture shows the cupping close to the fretboard extension. Last one is of the crack.

The finish looks like lacquer, but I have no idea if the pickguard is celluloid or not. I'm assuming it doesn't really matter, because you can see the shrinkage in the third picture. The only thing I'm concerned about is that the cupping starts all the way from the edge of the top (first picture).

Also, do you guys have a preferred wood for cauls? From the pictures Frank posted it looks like he's using two 3/4" pieces of plywood glued together.

Thank you!

[Frank Ford]

I'd say it's the textbook situation there, and I'd release/reglue the pick guard with TItebond.  Also, I'd want to reinforce the crack alongside the fingerboard - that one can get nasty.

[eliya]

Thanks Frank. I'll reinforce the crack as soon as I fix the cupping, so the crack will be level.

[Mark Pollock]

I'm facing a similar repair, but was thinking of sealing the bare wood with a few coats of shellac and then using adhesive film to reattach the guard. Is there a reason that this is preferred, other than the time commitment?

[eliya]

I'm far from an expert, but what would be gained by doing this your way? What I really like about Frank's method is that the wood fibers would find themselves back into where they were, and that you don't have to spend a lot of time making sure you glue back the guard exactly where it was.

[Mark Pollock]

The only reason, and it's not much of a reason, is that it can make it easier to do the repair again in 50 years, and might allow the guard to slip a bit as it continues to shrink. But perhaps the correct glue allows this slippage too. 

[Paul Verticchio]

Shouldn't the crack be repaired BEFORE the pickguard is restored/repaired? Just curious as that's how I'd approach it.

[eliya]

That could very well be the way to go. I obviously have no experience. However, right now the two "sides" of the crack aren't level, and I think repairing the cupping would fix that. At least that's what Frank did here with a similar crack and sunken pickguard.

[Paul Verticchio]

But you guitar's crack is in a very sensitive, high stress area.Yours may require a completely different (more complex) approach.

What Frank corrected in that photo essay was the classic Martin pickguard crack.  Those are the most basic and 'simplest to fix cracks' on an acoustic.  Also, the repair to the PG is for a completely different problem. The question that comes to my mind is "Why did your PG shrink (cup) in the first place?" It could be due to age & the settling of the top OR it could indicate a structural issue. I'd try to solve that issue before proceeding. Any successful repair starts with a thorough diagnosis.

We'll see where this goes, eh? :) Best of luck :)

[eliya]

Thanks for the thorough reply, Paul.

At first I thought there might be a loose brace (or more than one) under the pickguard, but all the braces are glued tight, and I couldn't get a .002 feeler gauge between the braces and the top. Seeing Frank's repair documentation and this same problem led me to believe that it's the pickguard that has sunken in. You can also see the shrinking marks around the perimeter of the guard. Perhaps I'm wrong, though! Anyway, since the crack isn't flat, I'm afraid that repairing it first, and then repairing the pickguard area wood loosen the fix. Perhaps I'm wrong, though!

What else do you suggest looking into before embarking on the repair?

[Frank Ford]

That's it - pick guard first, then reinforce the crack alongside the fingerboard.  Without even seeing the guitar in person, I can say for certain that the pick guard shrank, causing the cupping.  That happens on virtually all these guitars with celluloid glued directly  to the wood.

Regluing the guard flattens the top, and the job goes quite well with little or no risk.  In the future the same repair can be repeated.

[Paul Verticchio]

Thank you, Frank. :)  The Master has spoken :)

[Mark Pollock]

"In the future the same repair can be repeated." 

That pretty much ends the discussion of my question. In the face of evidence, I must change my stance.