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1972 Martin D-12-28 12-String Guitar Restoration

On to another rebuilding project here in the Dungeon.

This one promises to be a bit more challenging than the ES-225.

This is a 1972 Martin D-12-28.  Someone started a neck reset and bridge replacement project on it and never finished, and offered it for sale as-is.  Then some idiot enterprising soul bought it with the thought of putting it all back together again.

That person would be me.

Here's what I plan to do:

  1. Remove the 'popsicle' brace in a quest for better tone.
  2. Remove the oversized rosewood bridge pad and replace it with a smaller one made of maple - in a quest for better tone.
  3. Make a new bridge of cocobolo in a quest for better tone.
  4. Repair a minor crack in the fingerboard.
  5. Fix some minor finish chips.
  6. Replace the missing 15th fret that was apparently lost when the neck was removed.
  7. Replace the pickguard with one made of tortoloid.
  8. Reinforce the hollow neck rod with a carbon fiber rod.
  9. Reset the neck.
I'll expand on each of these processes as I work on them.  In a nutshell, though, late 60s through early 80s Martins had a couple of interior changes (namely the huge bridge pad) that are tone-sapping.  My goal is to rebuild this guitar into one that sounds like one from the 1950s or earlier.  (If Martin had offered a 12-string back then).  In essence, I'm souping it up a bit.

You'll see that I have the original ebony bridge - which had been shaved to lower the string action and avoid the inevitable neck reset.  It looks like someone eventually realized the neck did need to be reset and planned to put a new rosewood bridge on.  Now, I have a hunk of cocobolo left over from my Gretsch ukulele project, and I've been wanting to use it.  I'm going to attempt to turn it into a 12-string Martin bridge.

If that fails (possible), I'll just use the rosewood bridge.

 What we're looking a here is the 'popsicle,' or tongue, brace.  Older Martins don't have this brace.  You can see it between the neck block at the top and the cross brace just above the soundhole.

The idea is that this brace prevents splits here.  Now, there is a lot of controversy over this brace and its effect on tone.  Some folks remove them in the belief that it will improve tone - i.e., that the top can vibrate more in this area if the brace is gone.  And that the brace isn't really needed.

I can go either way, but I figure I'm going to remove this one as a test.

And here we have the notorious Martin rosewood bridge plate.  It's believed that Martin put these on its guitars beginning in the late 60s to prevent the top 'bellying,' or lifting behind the bridge.  It probably does, but it also is a major tone-sapper due to its size and thickness.

I'm going to take it out and replace it with a custom maple pad.

Good luck to me.

Here's where the original bridge was.  Whoever took the old bridge off did a good job.  Very little spruce came up with the bridge.

I can't understand why there is glue/gunk in the pin holes - but I'll be drilling that out anyway.

I'm armed with my interior parts removal tools and ready to go to work.

The Complete Martin Guitar Restoration Saga
Restoration begins (This page)
Repairing heel break
DIY chisel for bridge plate removal
DIY bridge plate removal iron, Pt.1
DIY bridge plate removal iron, Pt.2
Steam removal of bridge plate
Bridge plate removed
Tongue brace removal
Crack repair and brace scallop
New bridge plate Pt. 1
New bridge plate Pt. 2
Patching hole in top
Final fitting of top patch
Installing carbon fiber rod
Fret removal
Fingerboard crack repair, Pt. 1
Fingerboard crack repair, Pt. 2
DIY fret bender tool
Refretting Pt. 1
Refretting Pt. 2
Tuner shaft repair
Neck reset - dovetail fitting
Measuring neck set with DIY jig
Gluing the neck with hide glue
Tortoloid Pickguard
Fitting bridge pins
Brace reglue
Making bone saddle
Making a buffalo horn nut
Restoration completed


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