DIY Network

Gilded Frame: Gilding Process From "Wood Works" episode WWK-601

	The silver-leaf gilding on the frame is enhanced through a patina process brought about with a chemical reaction.
	The "knuckle test": Lightly drag your knuckle along the surface. If the surface makes a squeaking sound, the size is ready for gilding.

In this episode of DIY Wood Works, host David Marks builds a hardwood picture frame with spline-mitered joinery and a raised decorative bead. With the frame structure built and reinforced with spline joinery, work can now begin on finishing the frame with gilding of silver leaf and a chemically produced patina.

Gilding with silver creates a lustrous finish with depth and texture that could never be achieved with paint alone. When used on a frame, it adds elegant and dimension to the art being displayed.

Materials:

Paint sprayer
Primer (white-pigmented shellac)
Clear de-waxed shellac
Cobalt-blue Japan paint
Gold-size
Silver leaf
Wax paper
Gilding tools
Potash sulfurated solution
Sodium Sulfide
Gause
Safety glasses or goggles
Protective rubber gloves
Respirator mask

Safety Alert: Always wear protective gloves, and ensure adequate ventilation, when working with wood stains, solvents and other toxic solutions. When working with some chemicals or sprays, a respirator mask is required.

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Silver-Leaf Gilding and Patina

• The first step in the gilding process is to prep the frame using white-pigmented shellac as a primer (figure A). Spray on three coats. Between each coat, allow the shellac to dry, then sand the surface with 220-grit sandpaper to smooth the surface.

• To create a mechanical tooth for the next layer of paint to adhere to, sand the primed surface to 320-grit (figure B).

  Safety Alert: Always apply spray-on pigments and chemicals in a well-ventilated area and wear a good-quality respirator mask

  Figure A

  Figure B

  
  

  Figure C

  
  
  

• Once the surface is thoroughly primed, we opted to apply a base coat for the gilding of cobalt-blue Japan paint. This specialized paint is made from finely ground particles of pigment and is used as a backing color for the silver leaf. The rich, blue color will show through any of the subtle gaps and cracks in the leaf once it is applied, creating an effect much like the veins of color in natural marble. Spray on two light coats of the Japan paint (figure C). Following each coat, allow the paint to dry and sand with 600-grit sandpaper.
  

  
  

• Once dry, seal in the Japan paint with two coats of clear, de-waxed shellac (figure D).

  Once the shellac dries, lightly sand the surface again with 600-grit sandpaper (figure E).

  Figure D

  Figure E

  
  

  
  
  

• To make the silver leaf adhere to the surface, an adhesive must be applied. The adhesive we used is called gold size, a fast-drying oil-based varnish. It's a good idea to filter it before application to remove any solid particles of resin (figure F).

  In a dust-free environment, brush the size onto one half of the frame (figure G). Once applied, it will take about an hour for the gold size to set up, or tack -- meaning that it's sticky enough to apply the leaf.

  Figure F

  
  

  
  
  

• Silver leaf is extremely fine sheets of silver that have been pounded or rolled to a thickness much thinner than paper. Typically the leaf comes in books of 25 sheets that are 3-3/8" square (figure H).

• Some of the tools needed for the gilding process (figure I) include a goat-hair brush for tamping the silver down to the size, a soft brush for brushing away excess skewings, a leather pad (known as a klinker) for placing the sheets onto, and a gilder's knife for cutting and placing the sheets.

  Figure H

  Figure I

  
  

  
  
  

• Once the size has set up, you can begin work applying the leaf.

• Tip: A good method for checking to see whether the gold size is tacky enough is to lightly drag your knuckle along the surface. If the surface makes a squeaking sound, the size is ready for gilding.

• To apply the gilding, start in one corner and carefully apply the sheets to the tacky surface. Tamp it down using the soft brush (figure J).

• Continue carefully working your way around the sized frame (figure K).

  Figure J

  Figure K

  
  

  	Figure L
  	Figure M

  
  
  

• As you proceed, burnish the applied silver using wax paper (figure L) to help the leaf adhere to the size. Rub the wax paper with your fingertips, carefully working the leaf into the details, while holding the paper steady so that it doesn't slide and scratch the silver. Avoid touching the silver at this point as the oils on your fingertips could cause the surface to oxidize.

• To create a texturized surface that will let some of the blue color to show through, add thin strips of wax paper and dental floss to the sized surface (figure M). These pieces are termed resists and create a void in the gilding, allowing the color underneath to show through in the negative spaces.

• Once you've worked your way around the first half of the frame, apply the size to the second side, allow it to set up and then gild it.
  

  	Figure N
  	Figure O

  
  

• After allowing 12 hours for the size to completely dry and the silver to bond, you can begin the process of cleaning away the excess leaf. The excess pieces that fall away are known as skewings. Brush off the excess silver with a gilder's mob or soft brush (figure N).

  Tip: You may want to collect and save your silver skewings in a jar for possible use later on another gilding project.

• You can now carefully remove the strips of wax paper and dental floss to reveal the contrasting color underneath (figure O).
  

  	Figure P
  	Figure Q
  	Figure R

  
  

• At this point, you could opt to apply a lacquer sealer to protect the silver from tarnishing. However, we opted to take the gilding one more step, with a chemical patina, to add even more texture and color to the finish. To create the chemically induced patina effect, we used two chemical solutions -- potash sulfurated and sodium sulfide.

  Safety Alert: These chemicals are toxic. Wear protective rubber gloves and follow necessary safety precautions for working with toxic chemicals.

• To apply the potash sulfurated solution, soak strips of cheesecloth in the solution then drape them over the frame (figure P) and press them down using wax paper. The cheesecloth will imprint a texture onto the silver leaf.

• As the chemical begins to react with the silver leaf, it will create a tarnish effect and an aged look featuring gold and reddish color that contrasts against the blue surface underneath (figure Q).

• Setting the treated frame in direct sunlight will help further the oxidation process and transform the once-shiny silver to a textured field of metallic colors and shades (figure R).

  Important: Watch the oxidation process and avoid leaving the chemicals on for too long, as they will eventually turn the silver to black.

• If you find any areas that have remained unoxidized, you may want to use a spray bottle with the sodium sulfide solution to help soften the highlights to a warm pewter tone.

RESOURCES :

Woodworking Techniques: Best Methods for Building Furniture from Fine Woodworking
Author: Editors of Fine Woodworking magazine
Publisher: Taunton Press
ISBN: 1561583456

Fine Woodworking: Making Picture Frames
Author: Stuart Altshuler
# 014032
The Taunton Press Inc.
Website: www.taunton.com

David Marks Website
David Marks, DIY's Wood Works host, is a master woodworker. For more information on cut sizes and project details, please contact him via his Website at www.djmarks.com

Fine Woodworking
A magazine devoted to high-quality craftsmanship in woodworking.
The Taunton Press Inc.
Website: www.taunton.com