11/21/14

Repairing Top Cracks on the Vintage Gibson TG-1

You may recall I have a ca. 1931 Gibson on the workbench for some crack repairs.  I've gotten back to working on it.

There are a couple of side cracks, but the trickiest to repair are these top cracks and breaks.

The guitar took a hit near the edge of the rim, probably on an angle.  The hit caused a couple of long cracks to open along the grain lines - see the red arrows.

And there are also some breaks across the grain which didn't go through the top - they split horizontally.  Those are the areas the green arrows point to.

I need to open up the long cracks, as well as the splits, to get glue into them.

I carefully used a very small flat-bladed screwdriver to lever the top upward.  Then I wedged some other small screwdrivers under the split 'planks' to hold them open.

Now we can get glue into those joints.

Not surprisingly, one of the cracked pieces broke off during this operation.

You can see how the piece was broken - the spruce is actually split in half horizontally.

In fact, three pieces came off.  This is actually a good thing, because I will now be able to get glue under them and glue them back into place.  With luck, they should fit back exactly where they came from.

I'll do that as Phase 2 of this repair.  For now, I want to get the large cracks glued up.

Did you know Paul Prudhomme makes hide glue?  Dig it!

(I accidentally broke my trusty Felix hide glue jar; it cracked after being heated and cooled so many times.) 
Into the hot water bath it goes, heated to 145°F (or 62.77°C).

I heated the cracks up a bit with a hot air gun to give me some extra working time...

... then I used a small paintbrush to apply the glue.

I worked so fast that my camera didn't have time to focus!

Then I pressed the cracks down flat.

And clamped the whole thing down.  There's a sheet of waxed paper between the top and the caul on the top of the guitar so the caul won't get stuck onto the guitar.  That would be a disaster...I shudder just picturing it in my mind.

There's also a caul on the bottom - both are there to protect the guitar.

Here's the repaired area after the glue has dried.

I'm pretty happy with it.  The cracks are all flat and the repair is very solid.  The ugly spot where those pieces are missing looks bad, but I'll glue those pieces back in next and it'll look much better.


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