DIY Network

Handmade Mandolin, Part 6: Decorative Binding From "Handmade Music" episode DHMM-106

The Gibson F5 is regarded as "the holy grail" of mandolins.

In this segment of DIY's Handmade Music, luthier Lynn Dudenbostel adds decorative binding to the outside edge of the instrument. But before he does, he takes the opportunity to talk about an original Gibson F5 that's in his shop for repairs. It's vintage mandolins like the classic Martin F5 one and the luthiers who built them that inspire the design and the techniques used in construction today. Modern makers and repairmen like Lynn Dudenbostel relish every opportunity to study the great ones.

The one shown in the figure at right was built in the 1920s and was originally owned by Earle Taylor who played in a group called The Stony Mountain Boys -- the first bluegrass group to ever play Carnegie Hall. This particular instrument was also reportedly played by the legendary Bill Monroe on several occasions.

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The Archetypal Mandolin: The Vintage F5

The original Gibson F5 mandolin featured in this segment was built in the mid-1920s. This particular model is commonly referred to as the "fern" because of the ornate inlay on the head stock. This particular instrument (figure A) originally belonged to a famous musician named Earle Taylor who played with a group called The Stony Mountain Boys -- the first bluegrass group to ever play Carnegie Hall. Reportedly, Bill Monroe also played this particular mandolin on several occasions. Despite considerable wear to the body and neck of the instrument (figure B), this mandolin maintains a wonderful sound.

Figure A

Figure B

It's mandolins like this that serve as a model and basis for the work that contemporary luthiers like Lynn Dudenbostel do. While this historic instrument is in his shop for repair work, Lynn takes the opportunity to study the various aspects of its construction.

"What's of particular importance to builders," says Dudenbostel "are the top and back thickness measurements." Lynn uses an instrument known as a Hacklinger gauge (figure C) to take those measurements. Mapping out these measurements helps provide an understanding of what's necessary to re-create the distinctive sound of these classic instruments. This device has a small magnet that goes inside the instrument.

A scale on the side of the gauge provides readings for the precise thickness measurements, in millimeters, with respect to the instrument body (figure D). By taking numerous readings over the top and back of the instrument, luthiers can determine the graduations in thickness that help create the mandolin's sound. Later, they can attempt to recreate those graduations when they build their new instruments.

Figure C

Figure D

Lynn plays and studies an original Gibson F5. This particular instrument reportedly was once played by Bill Monroe, the father of modern bluegrass.

The Mandolin's Decorative Binding

Materials:

Table router
Celluloid binding
Instrument-maker's glue
Rotary tool
Carpenter's pencil
Safety glasses or goggles

Safety Alert: Always wear safety goggles or safety glasses when
working with wood, power-tools, saws, drills, routers, etc.
Steps:

• Inspired by the classic F5, Lynn can now finish the construction of his mandolin's body by adding celluloid binding to its perimeter. First he must cut a rabbet around the perimeter of the body to accommodate the binding. He measures the binding with a thickness gauge (figure E) and uses the binding itself to determine the exact dimension of the rabbet to cut around the perimeter of the body.

• At the router table adjusts the spiral bit and jig to reflect the measurement he comes up with. He then makes the cut in several passes to prevent chipping (figure F) The first pass creates a good ridge and after checking the progress he adjusts his fixture slightly and cuts away additional material.

  Figure E

  Figure F

  
  
• When it appears that the channel has been cut to adequate dimensions, Lynn checks it against the binding to ensure a good fit (figure G).

• The router can leave little spurs of wood along the edge, so Lynn trims them with a chisel to create a perfectly clean surface along the rabbet (figure H).

  Figure G

  Figure H

  
  
• As before, there's one spot a router-bit won't help -- around the scroll. Lynn sketches out a pattern that extends the rabbet around the scroll (figure I)

• He then cuts away the excess wood using a rotary tool (figure J). A good way to judge the skill of a luthier is check out the scroll. This is where good ones like Lynn earn their money. The precision is achieved freehand, and this technique can only be perfected through skill and experience.

  Figure I

  Figure J

  
  
• After additional cleanup with chisels, Lynn is finally ready to glue binding to the instrument using a two-step process. With super glue, Lynn attaches one layer of binding with a white surface facing out (figure K). Typically he starts with the scroll and works out and around the top.

• When finished with the first layer, he adds another layer with a tortoise shell design facing outward (figure L).

  Figure K

  Figure L

  
  
• This time he uses a gelatin mixture comprised of acetone and scraps of binding melted together to create a bond. In essence the acetone melts the celluloid material together and permanently bonds the strips. Lynn wraps the binding around the scroll and works down the instrument (figure M). He uses a heat gun to soften the binding a make it more pliable.

• Lynn's clamping method for securing the binding is a heavy application of masking tape (figure N).

  Figure M

  Figure N

  
  

  Figure O

RESOURCES :

Stewart MacDonald's Luthier Supply Shop
Website: www.stewmac.com

Luthier's Mercantile International, Inc.
Website: www.lmii.com

Pioneer Valley Luthier Supply Company
Website: www.pioneervalleyluthier.com

GUESTS :

Lynn Dudenbostel, Luthier
Dudenbostel Stringed Instruments
Knoxville, TN