Sunday, November 18, 2018

It's Mandolin season.

Here's a Neopolitan Bowl back mandolin which came in for repairs.

Its condition was reasonable for its age. The case was in a bad state.

The mandolin had lost its original bridge saddle. In its place someone had made a crude replacement which lifted the string action above a playable height.

The bowl back was split in several places but overall it was sound.

The frets had worn unevenly and needed levelling and crowning.

I repaired the cracks in the bowl and refinished the surface, removed the machine head tuners, re polished the head and neck, levelled and crowned the frets and fabricated a new bridge saddle.

String height and intonation are now as good as it gets.

The case was restitched. I sewed a new leather handle and new lid fastening toggles. I located some fresh red felt and patched up the interior. Lastly I refinished and waxed the exterior of the case. It still shows its age but is now intact and will continue to protect its contents for a further 100 years with good care.

Saturday, September 8, 2018

An old Neopolitan Mandolin comes in for repair.

I found that the neck joint had failed, the frets were worn, the saddle height and
intonation were going to need adjustment after the neck joint re set, the finish
was scratched and the strings needed replacing.

Buckled tail piece.

Failed neck joint

The dirt of ages.

Stripped and ready for repair.

Neck removed using a hot clothing iron and spatula.

Neck joint block is Poplar, not a particularly strong timber for this application.
The wood grain failed rather than the glue joint.

Next remove all traces of hide glue.

Mask and ready for glue.

Clamp joint in 2 dimensions.

While I was at It I decided to restore the case as well.
When I received it the mandolin fell out of the separation between base and the sides of its
original cardboard case, I removed the hard ware and re glued the separated parts and re papered
the exterior with Black Japanese paper and replaced the green felt lining.

Frets levelled, crowned and polished, intonation, string height, all spot on.
Re activated the shellac finish. What a surprising volume and tone this little  mandolin reveals!

One happy customer!

I coated the case with epoxy varnish to protect the paper finish. Looks like new again.

Sunday, June 10, 2018

Baby Taylor Disaster.

My latest mission?

To repair this.

Baby Taylor after altercation with Airport Baggage Handlers. Gig bag protection is just not enough folks!

Sound board separation

Bridge separation

Neck joint separation and neck fracture
 The owner of this guitar had attempted a repair to this neck joint but failed to make a proper connection. I wrapped the joint in a damp towel over night which softened the PVA wood glue.
Luckily for for everyone it separated cleanly.
Neck Joint separation

Neck joint separation.

Neck and head stock separation.
Head stock finger joint

Neck finger joint
Bridge removed
 The bridge was partially lifted on account of the distortion of the sound board so I removed it using a pallet knife and a hot clothing iron. I discovered that Taylor attached this bridge with double sided tape! The problem with this adhesive is that it is terribly difficult to remove. The tape residue is rubbery so all traces have to be scraped off before the bridge can be re-glued with wood adhesive.

Sound board re glued
The threaded rod is used to push the rib of the lower bout back outward under the edge of the sound board. the damage to the guitar plus the lack of kerfing meant the the rib had distorted inwardly. I made an adjustable rib thruster by running a nut and washer along the length of threaded rod and adjusted it until the rib and to aligned perfectly.

detail of neck finger joint fracture repair.
 The Neck fracture was a problem. The crack runs at an angle to the grain, lifting the finger board between the nut and the first fret. The crack also distorted the fit in the first finger joint grove.
Detail of neck finger joint repair
I drilled a 3 mm hole into the valley of the first finger joint, deep into the crack. I then fitted a PK screw into the hole to force the joint apart. I was then able to clear the splinters. I then removed the screw and forced wood glue into the hole then blew the wet glue into the fracture with compressed air
Clamping Jig for neck joint repair
 I built a jig to support the neck in every dimension to allow clamping force to be applied to the freshly cleaned finger joint. I made a tiny sanding board with which to sand the inner surfaces of the finger joint to remove all traces of glue. I dry fitted and trial clamped the joint, spot on!
Clamping Jig for neck joint repair

Clamping Jig for neck joint repair

Detail of neck Joint repair

Detail of neck Joint repair

Detail of neck Joint repair

Sound Board lower bout repaired

Checking lower bout sound board repair interior.
Note lack of kerfing blocks

Sound board reconnected and bridge re-glued.

Refinishing soundboard
The Baby Taylor guitar is getting a refinish on the neck and sound board. On the Taylor website the Baby Taylor and a number of other lower end guitars in their range are finished in what they call Varnish. I can confirm that Taylor's so called "Varnish" is in fact shellac. The surface finish is soluble with Methylated spirit. Shellac is hellish to sand as it galls up sand paper very quickly.

Baby Taylor with fresh shellac finish.

Baby Taylor with new set up and new strings. The saddle had never properly fitted the pocket in the bridge. Once I began adjusting the fit it dropped right in to the bottom of the slot and resulted in ultra low string height. I shimmed the saddle up with copper which brought the saddle height up by 2 mm!
Now it's all tuned up and settling in nicely. it has a big sound for a small guitar, the lack of bracing and kerfing probably accounts for that.