Sunday, December 29, 2013

Two Mandolins - Rainy Day Man

Now simple pleasures they all evade you, store-bought treasures, Lord none can save you.
Look for signs to ease the pain, I said ask again, go on and pray for rain.

The second mandolin on my repair bench proved to be a bit more challenging.  At first, the owner and I thought it would take little more than reattaching the fret board, repairing some binding, repairing some non-structural surface cracking, a thorough cleaning and putting on a new set of strings.  It turned out this old mandolin had been worked on before and was in need of additional top and brace repairs.  According to the owner, this instrument spent a lot of time over the past few years in extremely dry conditions.  So, I was not terribly surprised when I found the top beginning to cave in under the tension of a new set of strings.  The last few times I've had a chance to work on this mandolin have been dreary, rainy days.  Considering how dry this mandolin had been, all the moisture in the air could only have helped.

The case of this mandolin has both historic and sentimental value.  Note the Delta Airlines unchecked baggage tag.

The fretboard was detached when I first inspected this instrument.  The binding for the most part was in great shape, and the dovetail joint was still holding together well.

The intricate binding was split at one of the seams but was intact.  With a little minor probing, I started finding out how brittle and fragile the wood and binding were at this corner.  A little taping after some CA and acetone were all it would take to fix her up there.

After removing the few remaining strings and her tailpiece cover plate, I started thinking about the order in which I would make the repairs.

I used some steam to clean off the old glue and make sure there weren't any hidden cracks in the fretboard.

After removal of the pickguard, I found evidence of an old repair.  Despite the top showing signs of distress, there was a repair cleat behind the crack that made things appear to be structurally sound.

With the mating surfaces clean of the old adhesive, I roughed things up with light sandpaper to prepare them to be reattached with hide glue.

After clamping and cleaning up the excess glue, I brought the repaired mandolin indoors and kept her in there for a few days while the hide glue dried.

Satisfied with the reattachment of the fretboard, I removed the clamps and moved on to repairing the surface cracks with yellow carpenters glue.

Some scraping and sanding with a small file, sand paper and steel wool took care of most of the remaining squeeze-out glue and final cleanup of the seam between her fretboard and neck.

A small amount of the fretboard binding had come loose in the process.  I used a little CA to make the repairs to it, as I eventually did with the top panel body binding repair she needed.  While the CA dried, I removed her tuners and began cleaning and polishing all of her exterior surfaces.

As I prepared to put the strings on, I noticed some separation at the back panel.  After applying some hide glue, I applied some painters tape to hold things in place, and moved on to stringing up this mandolin.

As I applied tension to the strings, the condition of the top became apparent.  Clearly, some additional repair work was required.  I contacted the owner with the bad news, and we agreed it made sense to make the structural repairs at this time.  Determining the full extents of  necessary repairs and making them through the sound hole would not have been possible.  So, the next step was removing the back of this mandolin from her sides.

Starting at the corner of the back I had just repaired, I used a combination of sharp tools and heat to release the glue bond between the back and sides.  Fortunately, her back came off easily with minor collateral damage, and two of the back braces remained attached to the sides.  These two braces were enough to provide the required stabilizing force to keep the sides from warping while I assessed and made repairs to the top panel.

The middle back brace was barely attached to the back panel.  I used yellow carpenters glue for repairing this collateral damage.

With a little closeup inspection, I determined the root cause of the top panel failure was inadequate bracing.  Unlike the other braces in this mandolin, this one did not extend between the sides and top panel.  Although some instrument builders purposely leave the braces short to allow the top and bottom plates to vibrate, that clearly was not the design intent with the rest of the braces in this instrument, so I doubt it was the intent with this one.  More likely, it seems to me this short brace was the result of design or construction error or oversight.

To keep as true as possible to the original design, I decided to replace the brace.  In order to do that, I first had to remove the existing brace.

With full string tension, the fretboard had been pushing on the top and contributing to the forces that led to the failure.  Without string tension, the fretboard was pulling the top panel outward.  Neither condition is desireable without proper bracing, and realizing this was the situation also meant a neck reset was not out of the question at this time.  So, before removing the brace, I released the fretboard from the body, so it could be properly attached while making the bracing repair.

With the fretboard released from the body, I used a hot and sharpened putty knife blade to remove the the old brace along with the cleat from the previous top panel repair.

To help restore the intended convex shape to the body, I made the replacement brace with some camber.

To accommodate the longer brace, I cut into the generous side material just enough to form the two gaps needed to receive the brace ends between the top panel and sides.

I used a putty knife to apply hide glue between the top panel and fretboard, and then applied carpenters glue to the top panel and the new brace.  After inserting the new brace, I clamped things in place and cleaned off the squeeze-out from the brace, fingerboard and top panel surfaces.  It was expected to be a chilly night, so I brought the backless mandolin back into the house to sit while the hide glue between the body and fretboard dried.  It would have to wait a few days, so I took the opportunity to take care of a few other things around the house and shop and got caught up on this blog before starting in on reattachment of the back panel.

Sunday, December 8, 2013

Two Mandolins - Come On Up to the House

Well the moon is broken
And the sky is cracked
Come on up to the house

It was only some binding that had cracked on This Old Mandolin.  The past week was full of work, band rehearsals and other aspects of married life with children.  With a few things on the to-do list complete, it was Saturday evening when I had the time to get back to the repairs on this Kay L4 mando.

A few days before starting in on these repairs, I left some small pieces of binding strip in a shallow mason jar to dissolve within a combination of 100% acetone and tint.

One piece at a time, I added slivers of tinted binding strip back to the repair site with some CA.

Using a popsicle stick, I applied some of the binding/acetone/tint juice to fill in and smooth out the bumps and valleys.

Progressing from a rotary tool sanding drum to 200 grit sand paper to steel wool, I smoothed out the binding surfaces.

Just before touching up the color, I used a toothbrush to apply a mild abrasive.

It was too cold to spray this repair area with clear lacquer on Saturday evening.  After setting up the paint booth, I brought This Old Mando up and into the house and enjoyed some Sarah Jarosz covers of some Tom Waits songs while writing this entry.  There's always tomorrow.

Tuesday, November 26, 2013

Two Mandolins - Keep the Customer Satisfied

And I'm one step ahead of the shoe shine
Two steps away from the county line
Just trying to keep my customers satisfied,

About a week ago, a coworker asked me to price some repairs and maintenance on two family heirlooms.  The one mandolin is a Kay L4, and the other is unlike anything I've ever come across before.  Both had obvious signs of age and use, but appeared to be in or very close to playable condition.  After reaching agreements on the scope of work to be done and the price, I ordered some replacement parts.

Although the Kay is in the better condition of the two, it had some issues.  Some of the rear binding near her neck joint was loose, the inside of her case was showing some wear, and her tuning pegs were deteriorating.

Although there were some scratches in her finish, she mostly needed a good, thorough cleaning and waxing.

The owner was interested in restoring this mando to playable condition, but was not yet ready to replace the buttons on the original tuners or to replace the tuners entirely with donor parts from another mando.  Instead, we agreed it made sense to replace the tuners with an inexpensive set, and to save the original tuners to be refurbished or replaced another time.

Although the screw holes and other dimensions matched up with the original set, the new set had two more screw holes per side.  To avoid altering the headstock, I decided I would leave the additional screw holes open.

The binding repair was next on the list.  It took a little CA glue with some painters tape to clamp things in place.

After stripping off all the grime and old wax with some Murphy's Oil Soap, I put on a coat of wax.

After removing the existing peg collars, I realized the new collars that came with the new pegs were slightly larger.  So, after cleaning and waxing the headstock, I cleaned the original collars and reinstalled them.

After applying some blue tape to affect the surrounding surfaces, I lightly sanded the grime and pitting off of her frets.

It was getting too cold to continue working in my shed, so I decided to leave the remainder of the binding repair for the next day.  I brought Kay inside, and put a new set of strings and her tailpiece cover back on her before calling it a night.