Regluing Fingerboard Extension on Guild F50

For what it's worth, I figured out why the fingerboard extension broke off the fingerboard.

There are two reasons actually.  The first is the join at the 15th fret was weakened because I had to drill 5 holes to get the steamer into the dovetail.  Now that I know how it was glued, I also know not to drill more than 2 holes as I usually would.

The other reason is that the wood around the same fret had swelled quite a bit - due to the steam.  So the extension curved downward more than usual.  When I reglued it, the angle made it such that it simply wouldn't stay glued - the joint wouldn't flex, so it just snapped.

Anyway, it's not a disaster. 

And now I'm going to reglue it to the body and fill the join.

I had lightly scraped the top of the guitar where the extension goes, as well as the bottom surface of the extension itself.

I also did some test fittings and measuring to ensure it lines up.  The drafting tape you see is there to use as an alignment.

Ready to glue!

I like to heat up the mating surfaces where possible with a heat gun - not to get them hot, but to get them warm so the glue has a bit more setting time.

After that, spread the hot hide glue onto the extension and the guitar top.

And clamp it down.

There's a caul inside the body to protect the big brace that runs under the extension from getting dented.

The radius block serves as the top caul.

A repair like this is an ideal place to use hide glue.  It has a high initial tack, and won't let pieces slide like an aliphatic glue would (e.g. Titebond). 

As an aside - I mis-wrote something in an earlier post.  Hide glue is made from bovine hide, at least in the US.  Not equine hide.

Here's the extension after the glue has dried.  Looks good, I think.

Now I'll glue the two chunks you see on the guitar top back into place, and fill any gaps.