DIY Network

Handmade Mandolin, Part 10: Wood Stain and Shellac From "Handmade Music" episode DHMM-107

	Lynn chose a honey-colored stain for this mandolin. Staining is only the first step in finishing process. Staining is followed by the application of shellac and varnish. The final step is a technique known as a French polish.
	Kentucky Thunder mandolin-player Andy Leftwich plays one of Lynn Dudenbostel's custom handmade mandolins.

With the neck completed and joined to the body, the instrument is termed "in the white" -- which is a luthier's way of saying everything is complete except for the finish. Alhough Lynn Dudenbostel has completed the construction on the handmade mandolin, it is not ready to be heard. The wood finish does more than add to the look. It's also an important aspect of an instrument's sound.

In this segment, the mandolin's finishing process gets underway with applications of stain and shellac.

Materials:

Spray booth and paint sprayer
Stain
Shellac
Varnish
Paintbrushes
Rags
Sandpaper
Masking tape
Protective gloves

Safety Alert: When working with stains, varnishes, solvents and other toxic chemicals, work in a well-ventilated area. For some procedures, a ventilator mask is recommended.

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Wood Finish, Part 1: Wood Stain and Shellac

• Lynn preps the mandolin for the finish by raising the grain of the wood. He applies a small amount of water to the wood surface and carefully sands using 150-grit sandpaper (figure A). He repeats the process several times, using progressively finer grit sandpaper. For the final sanding he uses 220-grit sandpaper.

• He then masks off the cocobolo-wood fingerboard (figure B) and peg head with masking tape to protect the detail work during the staining process.

  Figure A

  Figure B

  
  
  
• Rather than staining this mandolin in the traditional sunburst style of the original F5 mandolins of the 1920s, Lynn opts for a distinctive honey-colored finish for this mandolin. He applies a light, amber stain to the surface of the mandolin using a rag (figure C). A small amount of potassium dichromate is also used to give the instrument a vintage or aged look. Lynn applies a even coat of the stain and allows it to dry overnight.

  Lynn assesses the look of the wood after each coat and decides whether to add more. In this case a second coat of stain is sprayed on (figure D).

  Figure C

  Figure D

  
  Staining is only the first step in the finishing process. After the stain has been applied, and has dried fully, the wood is sealed with shellac. Lynn applies the shellac, mixed with a small amount of the stain, using a sprayer (figures E and F). "The shellac acts as a binder between the wood and the varnish," he says. "That's kind of important to have that transition there. The varnish doesn't stick as well to bare wood as it does to shellac."

  Figure E

  Figure F

  
  

In the segment that follows varnish is applied, and the finish is finalized using an old-school technique known as French polishing.

RESOURCES :

Kentucky Thunder
For more information on the band that appeared in DIY's Handmade Music, Kentucky Thunder -- and to hear streaming audio and download samples of their music -- visit the website for Skaggs Family Records, www.skaggsfamilyrecords.com.

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