A Baroque guitar repair

Discussion of all aspects of early instruments, lutes, theorbos, vihuelas, Renaissance guitars and Baroque guitars.
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senunkan
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A Baroque guitar repair

Postby senunkan » Tue Nov 01, 2016 11:22 am

I received a Baroque guitar for repairs.
The guitar was damaged in an accident and the back was crushed with some damage to the sides.
The head was snapped from the neck.
So I was asked to examine the guitar and possibly restore the guitar as close to the original as possible.

Upon examination I concluded that the guitar is quite repairable.
The back's damage looks pretty bad but all the pieces should be inside the body itself so think should able to glue back nicely.
The neck was using V-joint and glued with hide glue so the break was virtually clean at the joint.
So no damage to the head/neck joint.
The side's damage is minimal.

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Damage to back

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Damage to head / neck

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Slight damage to sides

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Close up of the damage to back

After much consideration and some advice from the owner's luthier friend, we both agreed that removing the back is the way to go.
So I removed the binding first but weren't able to retain the binding during the removal process.
Next I use iron and steam over wet paper towel to heat up the joint
I carefully insert the palette knife to separate the back and sides linings.
The hard part was a the brace joining the sides.
The braces sit in a lining pocket but didn't budge.
In the end I manage to lift up the back slightly and insert a 2 mm chisel to chisel the brace free from the pocket.

Another hard part is at the heel area.
But after much heating and inserting I manage to dislodge the back from the heel.
Luckily the heel area is pretty small.

Image
Damage of the back extend to the upper bout.

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Removing the binding

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Heating the back and lining.
A wet paper towel underneath

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Inserting the palette knife to separate the joint

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Finally the back is off!

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Luckily all the missing pieces are intact.
Sen CL Goh
2013 Sen Goh (S - IR)
2010 Sen Goh (S - IR)
1996 Ross Gutmeier (C - IR)
Alhambra 4P
Yamaha CG110

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senunkan
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Joined: Wed May 24, 2006 10:08 am
Location: Singapore

Re: A Baroque guitar repair

Postby senunkan » Tue Nov 01, 2016 11:32 am

Next I proceed to glue up the back.
I am using hide glue as per tradition.
After gluing I used clamps to hold the back together.
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Gluing the back

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Using clamps to close the gaps.

Next I clean up the neck / head V-joint.
Though I believe the original glue used was hide glue, still I better clean the joint to get a clean surface.
Then I proceed to glue in the reinforcement for the crack seam.
I use a maple veneer which fits the back maple material.

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Cleaning up the head / neck joint

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Straighten the back with plastic as it was bent a little and adding maple veneer reinforcement for the cracks.

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I also sanded away the paper backing at the rose area.

Next, I removed those spoilt lining and re-glue those lining blocks.
Also I check the back braces in fact more of the back braced are OK.
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Removing spoilt lining blocks

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Re-gluing new lining blocks

Next, I finally closed the back for the baroque guitar.
I also shaped the head to make it more symmetrical.
Unfortunately I had a small accident cut which I plunge my chisel into my hands.
It was careless of me to hold the piece using hand only and directly in the path my chisel...
Always remember the hand is not a good clamp.

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Before closing

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Closing the box.

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Shaping the head using hand as clamp... bad decision.

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Minor accident with the chisel, as it cut the thumb and plunge into my hand near the ring finger.
Sen CL Goh
2013 Sen Goh (S - IR)
2010 Sen Goh (S - IR)
1996 Ross Gutmeier (C - IR)
Alhambra 4P
Yamaha CG110

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senunkan
Posts: 810
Joined: Wed May 24, 2006 10:08 am
Location: Singapore

Re: A Baroque guitar repair

Postby senunkan » Tue Nov 01, 2016 11:43 am

Next comes the binding.
I ordered some walnut as binding because of the colour match but the walnut binding has too much run-out
They broke while I was bending them.
In the end I use my IRW stock and they bend nicely!
Next I bind the body using tape and tighten with strings

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Bindings bent

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Taping the binding at first

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Followed by string.

After the glue had dried, I use plane and scraper to make the binding flush the body.
I also sanded the back and sides for refinish.

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Planing down the binding

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Scraping it flush

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Sanded the back and sides for refinishing

Next I glued the head.
I correct the skew and adjust the fit.
Make some caul for the gluing process.

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Adjusted the fit of the joint

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Glued the head to neck.
The cauls are on the fingerboard for the length wise clamp and behind the the neck.

The joint is tight now, there used to be some gaps in the head / neck joint.
Unfortunately I don't have the picture to show this part.
Now it's tight especially the part where the V mortise sits on the triangular tenon's shoulder.
I also corrected the skew in the head.
Now it's parallel to the neck.
But I need to widen the nut slots as a result.

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Close up on the joint

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The part where the head mortise sits on the triangle tenon's shoulder. Now it's closed up.

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Ready for finishing

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Back view

... will probably take a while as the owner needs to get the guitar back for practice for a concert.
After the concert I will resume the finishing.
Sen CL Goh
2013 Sen Goh (S - IR)
2010 Sen Goh (S - IR)
1996 Ross Gutmeier (C - IR)
Alhambra 4P
Yamaha CG110

HNLim
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Joined: Tue Jul 26, 2011 1:02 am
Location: Singapore - The City in a Garden

Re: A Baroque guitar repair

Postby HNLim » Tue Nov 01, 2016 1:04 pm

Well done!
1978 Yamaha GC30A - S/BRW
2012 Esteve Adalid - S/BRW
2014 Sen #5 - S/BRW
2016 HNLim - S/BRW
1974 S.Yairi 950 S/BRW -10-string-convert 2015
HN Lim 14-string - S/BRW - Self-made
HN Lim 15-string - S/NEW - WIP
1974 S.Yairi 800 : Retired

vesa
Posts: 347
Joined: Tue Mar 01, 2016 12:52 pm
Location: Sulva, Finland

Re: A Baroque guitar repair

Postby vesa » Thu Nov 10, 2016 4:59 pm

Very interesting to follow. Not too many instrument repair threads around.
Hope your hand is cured by now.
Vesa Kuokkanen

David Rubio ws. E. B. Jones 1979
Antonio Marin nr. 813 1995 (Bouchet)
Vesa Kuokkanen 2016

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Big bird
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Location: Tejas North

Re: A Baroque guitar repair

Postby Big bird » Thu Nov 10, 2016 6:00 pm

The owner of that guitar is going to be very happy with you.
________________________________
Randy ( Big Bird, it's what my grandkids call me)
2015 ESTEVE 7SR - 650/52 Spruce/EIRW
2016 ESTEVE 8 - 650/52 Cedar/EIRW

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senunkan
Posts: 810
Joined: Wed May 24, 2006 10:08 am
Location: Singapore

Re: A Baroque guitar repair

Postby senunkan » Tue Nov 15, 2016 2:42 am

Thanks everyone!
My hand is healed but I can still feel the pain on my left hand ring finger on certain stretches when I'm playing.
The poke cause more damage than the cut.
Sen CL Goh
2013 Sen Goh (S - IR)
2010 Sen Goh (S - IR)
1996 Ross Gutmeier (C - IR)
Alhambra 4P
Yamaha CG110


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