Turn Down the Edges
Add a Three-Dimensional Look and Feel to Flat Panels
by Tom Ellis
from Volume 20, No. 2, April 2001
Discuss this article in the Glass on Metal Forums

     A very simple hammering process can be employed on flat copper or silver panels that make the panel to visually appear thicker or heavier than it really is.  The edges of a flat piece of metal are turned down adding an exaggerated third dimension to the panel.  
     This not only has an aesthetic appeal for some works, but also adds strength to the edges of the piece.  The edges can be thought of as arches which support the rest of the metal.  It will minimize warping which includes the middle of the metal from becoming concave.  For hundreds of years this has been a method often used for preparing flat panels.  
     The example shown here is made from .040" thick (18 gauge) copper.  This metal thickness is suitable for works in cloisonné, champlevé (if doing champlevé or basse-taille, the metal can be etched or engraved prior to turning down the edges), stencils, sgrafitto, etc.  For painting enamel applications, the metal should be considerably thinner (.010" thick).  Thicker copper (i.e. .040" as above) may cause crazing or stress lines to appear in the painting enamel after firing.  
     The first step is to snip off the corner points (see figure 2) and then use a file to round out the corners.  Next the copper piece is positioned at a 45 degree angle on top of a piece of 1/4" or substantial thickness of steel plate.  A small ball-peen hammer is worked along the bottom edge of the metal panel (see figure 3).  Try to keep the hammer strokes aimed at the bottom edge of the metal going up no more than 1/4".  Do this to all four sides of the copper panel.  Attention is given to the corners so that they become almost "domed" or semi-spherical.  Continue to work all edges until there is an obvious "turn down" to the metal edges.  Make each side as uniform as possible.  The piece can then be placed top-side-up on the steel plate and with the flat head of the hammer, the metal is tapped lightly around the sides to make the bottom edges sit evenly and flush to the steel plate surface (see figure 4).  The copper is now ready to enamel.  
     After thoroughly cleaning the copper, Scalex is applied to the front of the piece and allowed to dry.  The back side is sprayed (from an atomizer or Preval sprayer) with a 50-50 mix of water and Klyr-Fire.  Counter enamel or the enamel you plan to use on the front is applied to the back and allowed to dry.  The piece is placed on Marinite board¹ and fired at 1450 degrees F.  
     The Marinite board gives complete support to the metal as it is being fired.  When cool, pickle the front in Sparex #2 (about 5-10 minutes).  Clean thoroughly and repeat the above process, applying Scalex to the back of the piece, over the fired counter enamel, let dry, apply enamel to the front of the piece and dry.  
     Set the back of the piece (covered with dry Scalex) onto the Marinite board (see figure 5).  Fire for 2-3 minutes at 1450 degrees F.  The Scalex that gets fired into the backing enamel leaves a deposit of clay on the surface of the enamel.  This makes the enamel surface less tacky and prevents it from sticking to the Marinite.  It also makes a good surface for gluing when mounting the finished piece.  The Marinite board is then used for continuing firing as the support for the work.  Since most of the entire piece is resting on Marinite board when fired, warping is virtually eliminated. 

Discuss this article in the Glass on Metal Forums

1. Marinite is a high temperature insulating board which stands up to enameling temperatures and can be used many times. It is available in various sizes through Thompson Enamel, Inc.