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- Herausgeber: John Wiley & Sons
- Kategorie: Geisteswissenschaft
- Serie: Architectural Metals Series
- Sprache: Englisch
ZINC SURFACES THE LEADING RESOURCE FOR ARCHITECTS, DESIGNERS, AND ARTISTS WORKING WITH ZINC Zinc Surfaces: A Guide to Alloys, Finishes, Fabrication and Maintenance in Architecture and Art combines the latest guidance and information about zinc surfaces into a single and comprehensive resource for architects and artists everywhere. The fifth book in the author's authoritative Architectural Metals Series, Zinc Surfaces offers a highly visual, full-color guide to ensure architects and design professionals have the information they need to properly maintain and fabricate zinc surfaces. Numerous case studies illuminate and highlight the theoretical principles contained within. Full of concrete strategies and practical advice, Zinc Surfaces provides readers with complete information on topics including: * The use of zinc in architecture * The history of zinc's use in design * How to choose the right alloy for your purposes * Surface and chemical finishes * Corrosion resistance of various alloys This book is perfect for architecture professionals, metal fabricators and developers, architecture students and instructors, and designers and artists working with metals.
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Seitenzahl: 487
Veröffentlichungsjahr: 2021
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Table of Contents
Cover
Title Page
Copyright
Dedication
Preface
CHAPTER 1: Introduction to Zinc
ELEMENT 30 ZN –
SPELTER
THE ZINC ATOM
HISTORY
ZINC MINERAL FORMS
ZINC IN ART
ZINC AS AN ARCHITECTURAL METAL
HEALTH AND HYGIENE
THE ENIGMATIC METAL
NOTES
CHAPTER 2: Zinc Alloys
INTRODUCTION
ALLOYING DESCRIPTIONS
INGOT ALLOYS
ZINC ALLOYS – ROLLED FORMS
ZINC ALLOYS USED IN ARCHITECTURE
WROUGHT ZINC ALLOYS
ARCHITECTURAL ROLLED ZINC
FORGED AND EXTRUDED ZINC ALLOYS
CAST ZINC ALLOYS
SLUSH CASTING
ZINC DIE CASTING
GRAVITY CAST ALLOYS
KIRKSITE
NOTE
CHAPTER 3: Finishes
INTRODUCTION
APPEARANCE AMONG METALS
MILL FINISHES
NATURAL ZINC COLOR
MECHANICAL FINISHES
MECHANICALLY ROLLED TEXTURES
PREWEATHERED ZINC SURFACE
CLEAR COATING WITH PIGMENTATION
BLACKENED ZINC
CUSTOM PATINA FINISH
DARK VARIEGATED PATINAS ON ZINC
ZINC OXIDE PATINAS
ZINC IRIDESCENT PATINA
GALVANIZED ZINC SURFACES
GALVANIZED STEEL STRUCTURAL SHAPES
DARKENING GALVANIZED STEEL
ZINC PHOSPHATE COATINGS ON GALVANIZED STEEL
ZINC FABRIC
OTHER METHODS OF APPLYING ZINC TO STEEL
ZINC ANODIZING
CHAPTER 4: Expectations
INTRODUCTION
NATURAL FINISH ON THIN SHEET MATERIAL
NATURAL FINISH ON THICK PLATE MATERIAL
NATURAL FINISH ON CAST SURFACE
PREWEATHERED FINISH
PREWEATHERED WITH ADDED PIGMENTATION
EXPECTATIONS – PREWEATHERED SURFACE
BLACKENED ZINC
COLOR MATCHING
CUSTOM PATINAS
FLATNESS AND VISUAL DISTORTION
CREEP
GALVANIZED SURFACE
DARKENED GALVANIZED STEEL
CHAPTER 5: Available Forms
INTRODUCTION
WROUGHT FORMS OF ZINC
PLATE
SHEET AND COIL
ZINC FOIL
EXTRUSION
TUBE AND PIPE
WIRE
ROD
WIRE MESH
EXPANDED METAL
PERFORATED ZINC
TEXTURED ZINC SHEET
ZINC ORNAMENTATION
CAST
SLUSH CAST
DIE CAST
SAND CAST
ZINC POWDER
CHAPTER 6: Fabrication
WORKING WITH ZINC
STORAGE AND HANDLING
CUTTING ZINC
SHEARING AND BLANKING
SAW CUTTING
LASER
PLASMA
WATERJET
PUNCHING / PERFORATING / BUMPING
FORMING AND BENDING
GRAIN DIRECTION AND ANISOTROPY
TEMPERATURE EFFECT ON FORMING
BRAKE FORMING
V-CUTTING
ROLL FORMING
SUPERPLASTIC FORMING
FORGING
EXTRUSION
MACHINING
SOLDERING
WELDING
FUSION STUD WELDING
RESISTANT WELDING OF ZINC
EXPANSION / CONTRACTION
BOLTING AND FASTENING
THERMAL SPRAY
HOT-DIPPED GALVANIZING
CASTING
DIE CASTING
SLUSH CASTING
PERMANENT MOLD CASTING
SAND CASTING
PLASTER MOLD CASTING
SPIN CASTING
NOTES
CHAPTER 7: Corrosion
INTRODUCTION
ZINC AS A PROTECTIVE COATING
GALVANIZED STEEL
ZINC ALLOY COATINGS ON STEEL
ZINC POWDER IN PAINT COATINGS
SHERARDIZING
THERMAL SPRAY
ZINC ANODES
BATTERY
WHEN ZINC DOES NOT PROTECT STEEL
ZINC CORROSION
INTERIOR EXPOSURES
EXTERIOR EXPOSURES
SHELTERED EXTERIOR SURFACES
UNIFORM CORROSION
UNDERSIDE CORROSION
WET STORAGE STAIN
GALVANIC CORROSION
DETERMINING FACTORS FOR GALVANIC CORROSION
DIFFERENCE IN ELECTRO-POTENTIAL
GEOMETRIC RELATIONSHIP
DISTANCE
ELECTROLYTE EFFECTS
TEMPERATURE EFFECTS
PITTING CORROSION
INTERGRANULAR CORROSION
STRESS CORROSION CRACKING
ZINC ARTIFACTS AND STATUES
DEICING SALTS
CHLORIDES
FERTILIZER
SAPONIFICATION
CORROSIVE SUBSTANCES IN PROXIMITY
NOTES
CHAPTER 8: Maintaining the Zinc Surface
INTRODUCTION
ZINC SURFACES
WHY A MAINTENANCE PROCEDURE
DEVELOP A MAINTENANCE STRATEGY
RESTORING THE PREWEATHERED APPEARANCE
EFFECTS OF DIFFERENT ENVIRONMENTS
PHYSICAL CLEANLINESS
CHEMICAL CLEANLINESS
MECHANICAL CLEANLINESS
GALVANIZED STEEL SURFACES
APPENDIX A: Brand Names
APPENDIX B: Select Specifications for Zinc
Reference
Index
End User License Agreement
List of Tables
Chapter 1
TABLE 1.1 Common Minerals of Zinc
TABLE 1.2 Metal Mining around the World
Chapter 2
TABLE 2.1 Zinc Categories in the Unified Numbering System
TABLE 2.2 List of Slab Form or Ingot Grade Zinc Alloys
TABLE 2.3 Alloys of Zinc
TABLE 2.4 Common Alloying Elements in Zinc
TABLE 2.5 Rolled-Zinc Alloys
TABLE 2.6 Alloying Constituents in Several Forging and Extrusion Alloys
TABLE 2.7 Approximate Mechanical Properties of the Forging Alloys
TABLE 2.8 Die-cast alloys
TABLE 2.9 Gravity Cast Alloys
TABLE 2.10 Approximate Mechanical Properties of the Gravity Cast Alloys
Chapter 3
TABLE 3.1 Sources of Various Zinc Finishes
Chapter 4
TABLE 4.1 Relative Gloss of Various Zinc Finishes and Other Metals for Compar...
TABLE 4.2 Approximate Anisotropic Mechanical Properties of Rolled-Zinc Sheet
TABLE 4.3 Continuous and Batch-Galvanizing Process
Chapter 5
TABLE 5.1 Comparative Attributes
TABLE 5.2 Wire Diameters Available in Zinc Alloys
TABLE 5.3 Available Zinc Rod Diameters
TABLE 5.4 Common Die-Cast Alloys of Zinc
TABLE 5.5 Comparison of Different Metals Considered for Casting
Chapter 6
TABLE 6.1 Shear Strength of Various Metals
TABLE 6.2 Approximate Thermal Conductivity of Various Metals Used in Art and ...
TABLE 6.3 Coefficient of Linear Expansion of Various Materials
TABLE 6.4 Casting Processes Commonly Used with Zinc
TABLE 6.5 Comparative Weights of a Thick Casting
TABLE 6.6 Mechanical Properties of Zinc
Chapter 7
TABLE 7.1 Electro-Potential Relationship of Metals in Seawater
TABLE 7.2 Various Other Coatings Similar to Galvanized
TABLE 7.3 Methods that Utilize Zincs Protective Nature
TABLE 7.4 Approximate Years of Service Before Signs of Steel Corrosion Are Vi...
TABLE 7.5 Rate of Corrosion in μm / Year
TABLE 7.6 Rates of Corrosion per Year
TABLE 7.7 Corrosion Categories
TABLE 7.8 Various Salts That Grow on Zinc
TABLE 7.9 The pH of Various Woods When Wet
TABLE 7.10 Various Organic Substances That Can Corrode Zinc
Chapter 8
TABLE 8.1 Various Types of Solvents
TABLE 8.2 Physical Cleanliness
TABLE 8.3 Working Temperatures for Deicing Salts
TABLE 8.4 Composition of Seawater
TABLE 8.5 Chemical Cleanliness of Zinc Surfaces
TABLE 8.6 Mechanical Cleanliness
List of Illustrations
Chapter 1
FIGURE 1.1 Sphalerite plus copper to make brass.
FIGURE 1.2 Periodic table.
FIGURE 1.3 Zinc hexagonal crystal structure.
FIGURE 1.4 Spangle of galvanized.
FIGURE 1.5 Zinc coating on steel using a controlled refinement of the coolin...
FIGURE 1.6 Galvanized that has weathered.
FIGURE 1.7 Zinc atom with two electrons in the other shell.
FIGURE 1.8 Diagram of a Horizontal Retort.
FIGURE 1.9 An example of modern Bidriware made from zinc.
FIGURE 1.10 Various ores of zinc.
FIGURE 1.11 Vaile Mansion. Example of early Victorian Era homes in the US....
FIGURE 1.12 Copper-plated zinc sculpture.
FIGURE 1.13 World War I Dough Boy slush cast zinc. Copper plated.
FIGURE 1.14 “Goddess of Liberty.” Texas State Capital Building. Erected in 1...
FIGURE 1.15 Zinc roofs in Paris.
FIGURE 1.16 Winery Cantina de Il Bruciato designed by Fiorenzo Valbonesi Ces...
FIGURE 1.17 Folly Theater in Kansas City, Missouri.
FIGURE 1.18 Mesker Brothers Kit Façade made of galvanized steel.
FIGURE 1.19 “Un-money.” Recycled blanks of zinc off-fall from penny manufact...
FIGURE 1.20 The names give to element 30 over the ages.
Chapter 2
FIGURE 2.1 Zinc casting of a boy and his dog.
FIGURE 2.2 Small ingots of HG zinc alloy Z15001.
FIGURE 2.3 Uses of zinc.
FIGURE 2.4 Examples of die-cast zinc used in small engine parts.
FIGURE 2.5 Diagram of a battery.
FIGURE 2.6 Zinc plate being continuously cast.
FIGURE 2.7 Examples of sheet zinc made from different manufacturers.
FIGURE 2.8 Zinc rooftop made of rolled zinc.
FIGURE 2.9 Interior surface with custom Hunter™ patina zinc panels.
FIGURE 2.10 Palau Sant Jordi, Barcelona. Designed by Arata Isozaki Marco Rub...
FIGURE 2.11 Anisotropic nature of rolled-zinc sheet.
FIGURE 2.12 Cast zinc “glacier wall” on the Legislative Assembly Building of...
FIGURE 2.13 Statuette replica of the Statue of Liberty made by slush casting...
FIGURE 2.14 Slush cast statuette. Early 1900s.
FIGURE 2.15 Gravity cast zinc panels. Sand cast. Alloy Z35631
FIGURE 2.16 Kirksite “wave” die.
Chapter 3
FIGURE 3.1 Zahner Engineering space. Natural zinc, clay-like appearance. Des...
FIGURE 3.2 Zahner Engineering space. Dark and stormy day.
FIGURE 3.3 Stainless steel, zinc, aluminum, and steel.
FIGURE 3.4 Wavelength and reflectivity of various metals.
FIGURE 3.5 Reflective surface as opposed to a diffuse surface.
FIGURE 3.6 Sand cast zinc surface and ceramic cast zinc surface.
FIGURE 3.7 Zinc planters.
FIGURE 3.8 Mechanical finish examples on zinc.
FIGURE 3.9 Textured zinc.
FIGURE 3.10 Preweathered zinc. Zinc carbonate preweathering on 2 mm thick zi...
FIGURE 3.11 Comparison of the zinc carbonate (left) and zinc phosphate (righ...
FIGURE 3.12 Grain direction of rolled zinc.
FIGURE 3.13 Preweathering of similar thicknesses of zinc performed by differ...
FIGURE 3.14 Thick zinc sheets showing a slight color variation on initial in...
FIGURE 3.15 Tinted zinc coating.
FIGURE 3.16 Blackened perforated and bumped zinc used as a bridge cladding. ...
FIGURE 3.17 Zinc sculpture. Kansas City Plaza.
FIGURE 3.18 Roano™ patina on rolled zinc alloy Z41121
FIGURE 3.19 Taubman Museum after 10 years of exposure.
FIGURE 3.20 Microscopic view of the Roano™ patina on rolled zinc.
FIGURE 3.21 Interior surface using Roana Zinc patina.
FIGURE 3.22 Taubman Museum surface compared to stone flooring with similar m...
FIGURE 3.23 Chocolate company Max Brenner™. Clad with shingles of Baroque pa...
FIGURE 3.24 Cast zinc statues of WWI solders copper plated to mimic bronze....
FIGURE 3.25 Children's Hospital of Richmond Pavilion. VCU Campus. Designed b...
FIGURE 3.26 Taubman Museum of Art. Roanoke, Virginia. Designed by Randall St...
FIGURE 3.27 Roano™ Zinc on the Taubman Museum of Art.
FIGURE 3.28 Polk County Criminal Court Building.
FIGURE 3.29 Hunter Museum of Art. Chattanooga, Tennessee. Designed by Randal...
FIGURE 3.30 Thick, white zinc hydroxide formation on a Donald Judd sculpture...
FIGURE 3.31 Hunter™ zinc on the Hunter Museum of Art.
FIGURE 3.32 Hunter™ zinc with different tones.
FIGURE 3.33 Hunter™ zinc on the Art Gallery of Alberta. Designed by Randall ...
FIGURE 3.34 Art Gallery of Alberta. Custom Trapezoid panels. Designed by Ran...
FIGURE 3.35 Other zinc patinas in development.
FIGURE 3.36 Additional patinas on zinc.
FIGURE 3.37 Melted zinc plate.
FIGURE 3.38 Iridescent patina on zinc.
FIGURE 3.39 Edge of galvanized steel.
FIGURE 3.40 Spangle on steel.
FIGURE 3.41 Aged galvanized steel.
FIGURE 3.42 Chrysalis structure made of galvanized curved tubing.
FIGURE 3.43 Darkening galvanized steel.
FIGURE 3.44 Darkened façade of the Morimoto's Restaurant in New York. Design...
FIGURE 3.45 Zinc “fabric.”
FIGURE 3.46 Test panels of zinc “fabric.”
Chapter 4
FIGURE 4.1 Carved steel sculpture by Reilly Hoffman. Hot-dipped galvanized c...
FIGURE 4.2 The percentage of copper and titanium added to zinc to transform ...
FIGURE 4.3 Dark spot of galvanized steel.
FIGURE 4.4 Zinc countertop. Image courtesy of Gary Davis.
FIGURE 4.5 Natural zinc planters after several years of exposure.
FIGURE 4.6 Cast zinc panels.
FIGURE 4.7 Cast statue at the Regis College Campus. Denver, Colorado.
FIGURE 4.8 Zinc sculpture with cracks from creep.
FIGURE 4.9 Preweathered zinc with the zinc carbonate surface. 2 mm thickness...
FIGURE 4.10 Preweathered zinc with the zinc phosphate surface. 0.6 mm thickn...
FIGURE 4.11 Seaside roof.
FIGURE 4.12 Deposits on the underside.
FIGURE 4.13 Zinc corrosion products leaching out from the back side of zinc ...
FIGURE 4.14 Dark streaks on weathered zinc surface.
FIGURE 4.15 Zinc guttering.
FIGURE 4.16 Thin zinc sheets with a Hunter Patina over a preweathered surfac...
FIGURE 4.17 Blue pigment coating on zinc.
FIGURE 4.18 Preweathered zinc surface as it appeared in 2000 and as it appea...
FIGURE 4.19 Slight lightening of the zinc surface from minute formations of ...
FIGURE 4.20 Zahner Engineering Space. Image courtesy of Dan Gierer.
FIGURE 4.21 Color variation visible in bright sunlight.
FIGURE 4.22 Variations in tone when viewed at different angles.
FIGURE 4.23 Custom patina Roano™ Barnard College New York. Designed by SOM A...
FIGURE 4.24 Max Brenner Chocolate Bar™ façade. Image courtesy of Tex Jerniga...
FIGURE 4.25 Stanford McMurtry Building, designed by Diller Scofidio and Renf...
FIGURE 4.26 Microscopic images and special relationship of a Roano™ surface....
FIGURE 4.27 Changes in color and appearance.
FIGURE 4.28 Roano™ surface on the Taubman Museum today and 10 years ago.
FIGURE 4.29 Changes to the Roano™ patina after years of exposure.
FIGURE 4.30 Changes to the Hunter™ patina after several years of exposure. T...
FIGURE 4.31 The venerable zinc roofs of Paris. Image curtesy of Gary Davis....
FIGURE 4.32 Black zinc panels displaying surface distortion.
FIGURE 4.33 Barnard College. Roano™ zinc patina on custom formed panel.
FIGURE 4.34 Section of panel with continuous stainless steel cleat.
FIGURE 4.35 2-mm-thick zinc panels for The Institute for Contemporary Art at...
FIGURE 4.36 Stages of creep. Time versus strain.
FIGURE 4.37 Zoo corrugated panels.
FIGURE 4.38 Hot-dipped galvanized steel plates.
FIGURE 4.39 Tubes with welded clips. Batch galvanized.
FIGURE 4.40 Weathered galvanized steel.
FIGURE 4.41 Hot-dipped galvanized defect.
FIGURE 4.42 Darkened galvanized steel used on the Diesel Building in Chicago...
Chapter 5
FIGURE 5.1 Rough cast zinc fence prototype.
FIGURE 5.2 Melting point in °C of various metals.
FIGURE 5.3 Cast zinc statuette.
FIGURE 5.4 Zinc clad Legislative Building of the Northwest Territories, Yell...
FIGURE 5.5 Continuous casting of zinc.
FIGURE 5.6 Zinc plate surface.
FIGURE 5.7 Zinc plate planter boxes.
FIGURE 5.8 Hunter™ zinc on 1.5 mm thickness zinc.
FIGURE 5.9 One meter wide preweathered zinc panels. 2 mm thickness.
FIGURE 5.10 Examples of coil weights and arbor diameters.
FIGURE 5.11 Variations of the preweathered option from various manufacturers...
FIGURE 5.12 Dome with Roano™ patinated shingles.
FIGURE 5.13 Peninsula Hotel Honk Kong. Zinc panel with zinc came at the join...
FIGURE 5.14 Custom perforated zinc examples courtesy of ImageWall.
FIGURE 5.15 Black zinc bridge panel.
FIGURE 5.16 Hammer tone texture in zinc.
FIGURE 5.17 Custom texture on zinc. Courtesy of Rimex.
FIGURE 5.18 Vaile Residence. Built in 1880 and restored in the 1960s. Indepe...
FIGURE 5.19 Stamped zinc forms.
FIGURE 5.20 Dough boy made by slush casting of zinc, then copper plated.
FIGURE 5.21 Cast zinc sculpture.
FIGURE 5.22 Crack from creep stress in outstretched leg.
FIGURE 5.23 Smaller compact zinc sculpture of a Shepard boy.
Chapter 6
FIGURE 6.1 White storage stain on the left edge of a patinated zinc surface....
FIGURE 6.2 Zinc wall with protective plastic peel coating. Removed after ins...
FIGURE 6.3 Damage to galvanized steel during storage and handling.
FIGURE 6.4 Waterjet piercing of zinc plate.
FIGURE 6.5 Custom-perforated ImageWall
®
and patinated zinc on Denver, C...
FIGURE 6.6 Black zinc custom perforated and bumped surface. Designed by Heli...
FIGURE 6.7 Perforated zinc used on the Cantina de Il Bruciato Winery, design...
FIGURE 6.8 Custom-perforated Baroque™ patina.
FIGURE 6.9 Custom bumped, 1.5 mm thickness zinc panels.
FIGURE 6.10 Patinated zinc panels formed from 2 mm zinc for a project in Jak...
FIGURE 6.11 Zinc sheet formed and rolled into a custom shape.
FIGURE 6.12 Grain direction on rolled zinc sheet and plate.
FIGURE 6.13 Bend with and against grain direction.
FIGURE 6.14 Zinc shingles of various shapes.
FIGURE 6.15 Structural matte systems composed of woven nylon.
FIGURE 6.16 Thicker zinc panel systems, folded and set off from the surface....
FIGURE 6.17 V-cut and conventional corner folds.
FIGURE 6.18 A stamped thin decorative spandrel panel.
FIGURE 6.19 Machining zinc coasters for Artizan™ zinc out of 6-mm-thick zinc...
FIGURE 6.20 Large penny art piece machined from zinc plate.
FIGURE 6.21 Assembled zinc ornamentation.
FIGURE 6.22 Welded v-cut zinc plate.
FIGURE 6.23 Stud-welding process.
FIGURE 6.24 Fusion stud weld. Stainless steel stud to zinc sheet.
FIGURE 6.25 A spot welding setup.
FIGURE 6.26 Thermal expansion and contraction of zinc.
FIGURE 6.27 Pullover condition caused by thermal elongation of the fastener ...
FIGURE 6.28 Machined and bolted connection on a zinc plate.
FIGURE 6.29 Corner detail of a horizontal corrugated galvanized panel.
FIGURE 6.30 Hot-dipped galvanized steel fabric.
FIGURE 6.31 “Frozen drapery” made from hot-dipped galvanized steel mesh and ...
FIGURE 6.32 Intricate detail achieved with cast zinc.
FIGURE 6.33 Slush cast Statue of Liberty. Several plates were cast and joine...
FIGURE 6.34 Zinc castings with intricate detail produced by plaster slurry t...
Chapter 7
FIGURE 7.1 Diagram of zinc coating on steel.
FIGURE 7.2 Inner workings of a zinc–carbon battery.
FIGURE 7.3 Corrugated galvanized steel sheet.
FIGURE 7.4 Loss of zinc in milligrams per square decimeters per day for a gi...
FIGURE 7.5 Sheltered surfaces.
FIGURE 7.6 Sheltered soffit with white zinc hydroxide forming along the inte...
FIGURE 7.7 White deposits on sheltered area of patinated zinc.
FIGURE 7.8 Roof exposed for 10 years in the Bahamas.
FIGURE 7.9 Zinc shingles with nylon fiber matte providing the ventilation sp...
FIGURE 7.10 Wet storage stain on zinc plates and on galvanized steel.
FIGURE 7.11 Crate of zinc sheets allowed to get wet and the subsequent stain...
FIGURE 7.12 Makeup of a galvanic cell.
FIGURE 7.13 Image of copper roof draining over galvanized corrugated panels....
FIGURE 7.14 Galvanic corrosion conditions.
FIGURE 7.15 Ratio of areas.
FIGURE 7.16 Galvanic circuit and means to prevent it from occurring.
FIGURE 7.17 Pitting developing on a zinc surface.
FIGURE 7.18 Cast zinc sculpture of a boy and a fish with crack.
FIGURE 7.19 Old zinc flashings and forms on a steeple in an urban environmen...
FIGURE 7.20 White zinc hydroxide on the underside of the Boy and a Fish scul...
FIGURE 7.21 Deicing salts reacting with the zinc and forming a stain.
FIGURE 7.22 Chloride fumes from a swimming pool.
FIGURE 7.23 Fertilizer staining on zinc.
FIGURE 7.24 Gold leaf releasing from zinc surface by means of saponification...
Chapter 8
FIGURE 8.1 Choices to the designer.
FIGURE 8.2 Damage from leaving deicing salts on the surface.
FIGURE 8.3 Maintenance being performed on a large zinc sculpture.
FIGURE 8.4 Zinc statue.
FIGURE 8.5 Galvanized steel bracket attached to a copper wall; 25 years of e...
FIGURE 8.6 Fingerprints on thin galvanized steel art form by Donald Judd.
FIGURE 8.7 Fingerprinting of zinc on left. After removal on right.
FIGURE 8.8 Smudges on patina zinc surface used on an interior wall.
FIGURE 8.9 Stainless steel cleaner affects the surrounding zinc surface.
FIGURE 8.10 Discoloration from adhesives.
FIGURE 8.11 Graffiti removed using common paint solvents.
FIGURE 8.12 L.F.Q. Printing on the surface of thin galvanized steel sheet.
FIGURE 8.13 Oxide stains on zinc.
FIGURE 8.14 Small zinc statue with severe rust staining.
FIGURE 8.15 Zinc sculpture of Neptune. Before-and-after stain removal.
FIGURE 8.16 Zinc oxide and hydroxide stain on a galvanized steel surface.
FIGURE 8.17 Image of stains on preweathered.
FIGURE 8.18 Hunter patina with an accumulation of zinc hydroxide on the lowe...
FIGURE 8.19 Changes in the ambient air and metal surface.
FIGURE 8.20 Deicing salts creating minor discolored oxide stain.
FIGURE 8.21 Coastal exposure. Zinc roof showing white dusting of zinc chlori...
FIGURE 8.22 Construction debris wash on patinated zinc surface.
FIGURE 8.23 Laser ablation on zinc surface with white hydroxide.
FIGURE 8.24 Example of packaging for zinc products.
FIGURE 8.25 Mar on zinc surface before and after treatment.
FIGURE 8.26 Scratch across panels during installation.
FIGURE 8.27 Cracks in zinc sculpture from creep.
FIGURE 8.28 Cast zinc sculpture with crack in dog's leg, filled with mortar....
FIGURE 8.29 Various thicknesses of galvanized and the expected lifespan.
FIGURE 8.30 Hot-dipped galvanized steel sculpture by R+K Design.
Guide
Cover
Table of Contents
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ZAHNER'S ARCHITECTURAL METALS SERIES
Zahner's Architectural Metals Series offers in-depth coverage of metals used in architecture and art today. Metals in architecture are selected for their durability, strength, and resistance to weather. The metals covered in this series are used extensively in the built environments that make up our world and are also finding appeal and fascination to the artist. These heavily illustrated guides offer comprehensive coverage of how each metal is used in creating surfaces for building exteriors, interiors, and art sculpture. This series provides architects, metal fabricators and developers, design professionals, and students in architecture and design programs with a logical framework for the selection and use of metallic building materials. Forthcoming books in Zahner's Architectural Metals Series will include Copper, Brass, and Bronze; Steel; and Zinc surfaces.
Titles in Zahner's Architectural Metals Series include:
Stainless Steel Surfaces: A Guide to Alloys, Finishes, Fabrication, and Maintenance in Architecture and Art
Aluminum Surfaces: A Guide to Alloys, Finishes, Fabrication, and Maintenance in Architecture and Art
Copper, Brass, and Bronze Surfaces: A Guide to Alloys, Finishes, Fabrication, and Maintenance in Architecture and Art
Steel Surfaces: A Guide to Alloys, Finishes, Fabrication, and Maintenance in Architecture and Art
Zinc Surfaces: A Guide to Alloys, Finishes, Fabrication, and Maintenance in Architecture and Art
Zinc Surfaces
A Guide to Alloys, Finishes, Fabrication, and Maintenance in Architecture and Art
L. William Zahner
Copyright © 2021 by John Wiley & Sons, Inc. All rights reserved
Published by John Wiley & Sons, Inc., Hoboken, New Jersey
Published simultaneously in Canada
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Library of Congress Cataloging-in-Publication Data
Names: Zahner, L. William, author. | John Wiley & Sons, publisher.
Title: Zinc surfaces: a guide to alloys, finishes, fabrication, and maintenance in architecture and art / L. William Zahner.
Other titles: Zahner's architectural metals series
Description: Hoboken, New Jersey : Wiley, [2021] | Series: Zahner's Architectural Metals Series
Identifiers: LCCN 2021003278 (print) | LCCN 2021003279 (ebook) | ISBN 9781119541615 (paperback) | ISBN 9781119541639 (adobe pdf) | ISBN 9781119541592 (epub)
Subjects: LCSH: Zinc—Surfaces. | Zinc—Finishing. | Zinc coatings. | Architectural metal-work. | Art metal-work.
Classification: LCC TS640 .Z34 2021 (print) | LCC TS640 (ebook) | DDC 661/.0661—dc23
LC record available at https://lccn.loc.gov/2021003278
LC ebook record available at https://lccn.loc.gov/2021003279
Cover Design: Wiley
Cover Images: (Main) Steven Holl Architects', Institute for Contemporary Art (ICA), Virginia Commonwealth University, photographed by Iwan Bann, c. 2017. (Border) Pattern on zinc plates © somnuk / Getty Images
This book is dedicated to my good friend Verne Christensen.
(a designer who proved Alessandro Volta's theory when we built a beautiful curved zinc roof below his copper gutters)
Preface
An expert is an ordinary man who- when he is not home – gives advice.
Oscar Wilde
Zinc is the mysterious metal used in art and architecture.
In the United States, it is a paradox. On the one hand, it is considered an Old World metal, used for centuries across Europe. Paris is defined by the roofs of zinc that blanket the city. Yet it is relatively new to North American architecture.
As a metal of art casting or fenestration, little was known until the early 1990s. Sure, we knew of the process of dipping steel in a molten jacket of zinc. Hot-dipped galvanized, a strange fondue for metal, is a process that is well known, but not always understood.
The leading zinc mines that supplied the world were once in the middle of the United States, a region with the town of Joplin, Missouri, as the center. Most zinc mining has ended in the area, but in the late 1800s and early 1900s this was the epicenter of zinc. Millionaires were made by the dozens as the area was tunneled out like a giant anthill.
In North America, the sheet metal industry, art casting industry, and design community knew little about zinc. Publications and training documents throughout the architectural metal industry made no mention of zinc. The old catalogs called the metal white bronze, perhaps attempting to elicit a feeling of noteworthiness by taking on the name bronze. Metal foundries, art schools, and metal workers in the United States lacked any real knowledge of the metal. With the exception of galvanizing, the metal was all but forgotten after the early part of the twentieth century.
When I first started work at Zahner, a 125-year-old metal fabrication company located in the Midwest, zinc was not known as an architectural metal. We did not stock the metal, nor was it specified in any industry publications. We worked with steel, terne, copper, aluminum, stainless steel, and lead, but not zinc. One of the first introductions to the metal occurred during the restoration of the Folly Theater, a turn-of-the-century theater built in 1900. When the workers removed parts of the metal cornice and decorative metal baluster in 1979, they had difficulty determining what the metal was. This metal had lasted 80 years and still looked in good shape. It was silver under the paint, so it was not copper. It was not magnetic so it was not terne-plated steel or galvanized steel. It was heavy, so it wasn't aluminum, and aluminum had not been in common use by 1900. The pieces were spun and assembled in sections by soldering. It was not any metal we were familiar with. It was zinc. From the old country.
The other connection to zinc goes back 125 years. Andrew Zahner, my great grandfather, started this metal company I work for, in Joplin, Missouri, in 1897. Back in the late 1800s, this region in southwestern Missouri, on the edge of the Ozark Mountains, was the site of one of the largest mining operations in America – first for lead used to make bullets and later for zinc. Zinc, known in the area as jack, made the region one of the wealthiest in the United States. Every major railroad at the time went through the Joplin region to transport the ore around the United States and to ports to supply the European market. The ore was of such high quality that the Europeans purchased it from Missouri.
This booming region attracted a young Andrew Zahner, and he started a small metal fabrication firm to produce cornices and other decorative features for the wealthy merchants in the area.
Andrew Zahner surely knew about zinc.
The boom / bust cycle eventually hit the Joplin area in the early 1900s, and Andrew moved the company to its current home in Kansas City. The knowledge of zinc was left behind with the dying mines of the central United States. Now, 125 years later, I write a book on this metal, zinc. It is unfortunate that I did not have Andrew as a resource.
Over the last couple of decades, we have worked with the metal zinc on numerous projects. We have expanded our knowledge of the metal and have uncovered many new and interesting ways of working with zinc. We have created new patinas and surface enhancements, and we have explored casting. The more I work with the metal zinc, the more I find it an intriguing material of design.
Working with my daughter Kat, who operates Zahner Metal Conservation, restoring 100-year-old zinc statues and statuettes gives a deep appreciation for how the artist worked with the metal and produced amazing detail using casting techniques that have all been forgotten.
This book, the fifth in the series on metals, is intended to spark the interest in the metal zinc and explore the possibilities it has to offer the designer and the artist. The next pages should help to unravel this interesting material of design and introduce the reader to how this metal will appear and function.
L. William Zahner
CHAPTER 1Introduction to Zinc
It's a business. If I could make more money down in the zinc mines, I'd be mining zinc.
Source: Roger Maris
ELEMENT 30 ZN – SPELTER
Zinc, the metal that could change copper into gold, at least that was the wish of the early alchemists. They called the metal counterfeht1. It looked like silver, but it wasn't. Adding it to molten copper and the copper would turn to a beautiful golden color, but it was not gold. It was an “imitation” a counterfeht. This odd metal, if it was a metal at all, was a mystery.
Zinc went also by the name spelter, used mainly by those who worked with the metal. Spelter was possibly a corruption of the name for “pewter,” the dull gray, lead-tin alloy. The Dutch, first to import the metal into Europe used the word, spiauter for a word to describe a mixture of lead and tin2. So, it very well may have been an early marketing ploy to give value to this dubious metal. Spelter was the name given to this metal up until relatively recent times. Today, the name zinc has firmly taken hold on the periodic table of elements.
Other names, in particular calamine, were frequently used for this metal before it was officially a metal. Calamine, the principal mineral of zinc, was the name used across Western civilizations since the time of the Romans. Calamine is zinc sulfide, and there are regions in Europe where the rich mineral deposits of zinc sulfide were mined.
Calamine, as well, lost out as a name for the principal mineral form of zinc and is now better known as the popular topical poison ivy cream, even though the lotion contains zinc oxide, not the zinc sulfide of the mineral form. Instead of calamine, the term sphalerite is used as the name for the zinc sulfide mineral. For a long while the term zinc blende, from the German zincblende, was also used to describe the mineral. Confusion reigned on what this mineral or metal actually was.
As a metal, zinc in a wrought or cast form came late, sometime in the middle of the sixteenth century to the Western civilizations, definitely earlier in India. China also was an early zinc producer, using crucibles with charcoal to heat the ore. They made coins from zinc in the fourteenth century. The Romans would produce brass from copper by adding calamine and heating it in small crucibles. The zinc was obtained by reducing the ore, releasing carbon dioxide, and the fumes of zinc would rapidly be absorbed into the copper. Once melted, the slag-covered block would be hammered and the bright yellow color would appear.
The process of making brass was well known throughout antiquity. The method of creating brass from sphalerite (or calamine, as it was then known) was described in several texts. One such text, Schedula Diversarium Artium, written by Theophilus Presbyter in the eleventh century, describes the heating of crucibles in an open furnace, adding calamine, then strips of copper. Place back on the furnace for 9 hours and you arrive at a golden yellow color pleasing to look at. Figure 1.1 shows the mineral sphalerite with a large lump of copper on a plate of brass.
Zinc appeared as a known metal later than lead and tin. The mineral was known but as a distinct metal, zinc was not. Along with other colorful zinc minerals, sphalerite was easy to identify and so was mined in antiquity as a mineral to add to copper to produce the beautiful yellow brass. Granted, it was often mistaken for galena, a lead sulfide mineral, at one time a valuable mineral for making bullets.
Early brass artifacts dating back to the eighth century BCE were uncovered in the Gordion tomb excavated in Anatolia. The copper–zinc metal was called oreichalkos and later orichalcum by the Romans. The process of producing brass was well known and documented. Most brass production was established near the zinc mines because it was easier to cart copper to the area, than the large quantity of zinc mineral needed.
FIGURE 1.1 Sphalerite plus copper to make brass.
The reason zinc as a known metal was late to discovery is the difficulty of refinement. Up until the mid-1700s, metals were made by roasting the ores and burning off the oxides to free the metal. Trouble is, zinc has a low boiling point as metals go. As sufficient heat is applied to reduce the ore, zinc turns to gas and the fumes escape. Thus, the reduction of the ore the way other metals are produced just did not work for zinc.
The way the early alchemists found this counterfeht, it would condense on the walls of the flue and in cracks and crevices of the stone after roasting metal ores that contained zinc. Zinc is often found in ores of other metals, particularly lead, copper and silver. When the ores were heated the zinc would go up as vapors and condense on the stone. When it condensed, it formed long, whiskery tuffs the alchemists called lana philosophica, meaning “philosopher's wool.”
Assistants to the alchemists would scrape and collect this wooly substance off the stone and out of the cracks of the flue walls. The alchemists placed a value on this special metal that was like tin but when added to copper would transform the copper into a golden yellow.
Alchemist symbol for zinc.
Zinc is a silver metal with a slight bluish hue. Zinc can be polished to a bright, silver but quickly tarnishes when handled. As zinc ages it turns to a rich gray color with whitish oxides in areas where moisture is allowed to accumulate.
Zinc is element 30 on the periodic table of elements, Figure 1.2. With the red metal, copper, on one side and gallium, a blue gray metal that melts in your hand, on the other, zinc falls in the twelfth row with cadmium and mercury.
Zinc has several isotopes, but the isotope zinc 67 is rather special. Zinc 67 occurs in approximately 4% of natural zinc. This isotope is highly sensitive to minute variations in transmitted energy. When it detects energy, it emits electromagnetic radiation making this isotope zinc 67 valuable for high accuracy measuring equipment. Zinc 67 is used to detect gamma ray vibrations with incredible sensitivity in the highly accurate atomic clock.
Zinc has a hexagonal crystal structure, which even though it is closely packed, it is less dense than the cubic structure of iron or copper. Figure 1.3. depicts a closely packed hexagonal crystal.
This metallurgical structure shows the crystal of zinc has six atoms in a near plane and another six slightly further away. This makes the bonds of the basal plane slightly stronger than the bonds of the parallel plane. This difference in distance and strength gives zinc an anisotropy that translates to forms made of zinc.3
FIGURE 1.2 Periodic table.
FIGURE 1.3 Zinc hexagonal crystal structure.
Another aspect of zinc is its ability to recrystallize rapidly after deformation. This prevents work hardening from occurring during forming operations and it also provides a level of “self-lubrication” as the crystals slip over one another during forming processes.
Note, the spangle that forms on galvanized steel is a large crystal of zinc that forms as it cools. It has the six triangular wedge-like symmetry reflecting the hexagonal crystal structure of the zinc crystal lattice. Figure 1.4 shows a close-up image of the spangle formed when zinc cools on a steel substrate. The wedges that expand out from a central point are called dendrites and the parallel lines are called subdendrites. When newly developed the galvanized surface has a crystalline reflective quality due to the way the subdendrites scatter the reflective light. The surface seems to come alive as you walk around a newly galvanized steel plate with the glittering reflection bouncing off the variations in the crystals.
FIGURE 1.4 Spangle of galvanized.
FIGURE 1.5 Zinc coating on steel using a controlled refinement of the cooling process.
This reflectiveness, achieved by hot-dipping steel into molten zinc, is a natural surface that forms due to slight imperfections in the zinc bath or slight roughness on the steel surface. These imperfections initiate the formation of the dendrite growth.
Artistic affects can be enhanced to take advantage of cooling rates of the molten zinc. These techniques are still in development in order to better understanding the parameters involved. However, cooling rates, “seeding” the molten bath with other elements can influence the effects.
The difficulty arises in the industrial controls in place by the galvanizing facilities. Artistic expression is not in their normal parlance.
Figure 1.5 shows a “wave-like” appearance that has developed on flat steel sheet. The reflectivity enhances the three-dimensional appearance of the zinc surface.
As the surface oxidizes, the zinc crystals still vary in appearance creating a dull, lower reflective patchwork appearance. The dendrites are still there, they have just developed a layer of zinc oxide that mutes the reflectivity. Figure 1.6 shows a galvanized plate that has been exposed to weather.
FIGURE 1.6 Galvanized that has weathered.
Zinc
ELEMENT 30
Atomic number 30
Crystal structure:
Close-packed hexagonal
Main mineral source:
Sphalerite (Calamine)
Color:
Bluish white
Oxide:
White
Density:
7,068 kg/m
3
Specific gravity:
7.0
Melting point:
419°C
Thermal conductivity:
112 W/m °C
Coefficient of linear expansion:
19 × 10
-6
m/m°C
Electrical conductivity:
26% IACS
Modulus of elasticity:
108 GPa
Most of the zinc found on the Earth's surface is from hydrothermal activity that brought the metal to or near the surface. Zinc is not found in the native state. Zinc is always found in combination with other elements and metals. Zinc is the 24th most abundant element within the upper crust of the Earth.
Zinc has a poor strength to weight ratio as compared to other metals used in industry.
Zinc alloys are ductile at room temperature. Zinc castings are not ductile.
Zinc is subject to fracture when formed at low temperatures.
High elasticity – resiliency under shock loading
Soft edge
Zinc and zinc oxides are nontoxic unless consumed in large amounts. Zinc oxide fumes are hazardous when inhaled and will cause flu-like symptoms that can last 1–2 days.
It has superior corrosion resistance in many natural environments. Zinc is subject to corrosion in low pH and high pH environments.
FINISHES:
Mill finish – as rolled
.
Semi-bright
Preweathered – darkened
Zinc can be painted.
Coil-coated zinc sheet in various colors are available on the market.
Oil-based paints are not recommended. Saponification can develop.
Plating with other metals such as copper, silver, nickel, and gold are possible.
Artificial patina:
Zinc can receive artificial patinas of white, black, browns, mottled browns with green and reddish oxides as well as iredescent hues of transparent greens, purples and reds.
Bright appearance:
Zinc can be polished but the luster quickly diminishes as oxides form. The color is typically a matte gray to grayish blue.
Reflectance of ultraviolet:
of infrared:
The oxide of zinc absorbs ultraviolet light. Its use in sun protection is well known. Protection is afforded by absorption of the ultraviolet radiation and not allowing it to pass to the skin. Zinc oxide in powder form is used extensively in paint. It is a white powder and will reflect infrared radiation.
Relative cost:
Medium
Strengthening:
Zinc does not gain strength from cold working as other metals do. Instead, alloying with small amounts of copper and titanium are used to improve strength and add creep resistance.
Recycle ability:
Zinc is easily recycled because of the low melting point. Zinc is captured in from galvanize coated steels as vapor during the recycling process of coated steels.
Welding and joining:
Zinc can be welded and soldered.
Casting:
Zinc is a common casting metal. Used for many small cast parts where strength is less a requirement
Plating:
Zinc can be electroplated with other metals.
Etching and milling:
Zinc can be etched chemically and readily machined.
THE ZINC ATOM
All metals have at most three electrons in their outer shell. Zinc, element 30 on the periodic chart, has two electrons in the outer shell. This gives it an oxidation state of +2, making the zinc atom divalent in all compounds. Figure 1.7 depicts a typical zinc atom with the two electrons in the outer orbit shell. For zinc, there is always two covalent bonds formed when the zinc atom combines with other elements.
Oxygen readily joins with zinc to form ZnO and Zn(OH)2, with oxygen alone making a double bond and the two hydroxide combinations each with a single bond.
FIGURE 1.7 Zinc atom with two electrons in the other shell.
High-purity zinc is a strong oxidizer and when exposed to the atmosphere quickly tarnishes and forms the oxide and hydroxide. The standard potential of zinc can be expressed thermodynamically4 as:
This represents a strong drive to combine with other elements.
HISTORY
The discovery of zinc as a metal is credited in the West to the Swiss alchemist, Paracelsus. Dr. Paracelsus, as he was known because he was a physician and a philosopher as well, in 1526, described a metal he called zinek, as one of the seven known metals. Paracelsus lived around Basel and wrote extensively on various subjects. He is credited, among other things, as the father of toxicology.
Zinc ore was mined in Germany for the making of brass in the region around the Harz Mountains. The nearby town of Goslar, Germany, was a center of mining and zinc mining existed from around 1550. By 1650, a large-scale zinc ore production and refinement was underway. The mines around this region produced iron, silver, copper, lead, and zinc.
The process of refining the metal still was a mystery to the west. China and India would supply the metal in a refined state to European companies for producing brass by alloying with copper. Eventually, by the middle part of the eighteenth century, zinc-mining operations in Sweden and the region around Silesia would become important sources for the ore.
In the early 1700s, Bristol, England, the Bristol Brass Company would import zinc from India. William Champion, the son of the founder of the company, created a method of smelting his own zinc using a process notably similar to one developed centuries earlier in India. The company previously would import the zinc to make its brass plates, now it could produce and refine its own zinc from ore. William Champion has been credited with the early manufacture of industrial quantities of zinc.
Champion saw how the metal workers in India were extracting zinc from the ore pyrometallurgically by adding a distillation process to capture the fumes and condense the zinc oxide. The zinc was heated to turn it into vapor, the vapor would condense on the cooler walls of a chamber similar to the way it would condense on the cooler stone walls of the alchemists flue. This condensed zinc was zinc oxide. The key was to remove the oxygen by adding charcoal to the heated chamber and this would remove the oxygen from the zinc oxide creating carbon dioxide and leaving the zinc as a lump of metal.
In those days, brass was the main product that set the demand for zinc. Brass was used to clad the hulls of English sailing ships. Muntz metal, an alloy of copper and zinc, contains 40% zinc. Developed specifically as a cladding for ship hulls in 1832, Muntz, named after its inventor, George Fredrick Muntz of Birmingham, England, replaced copper as an anti-fouling cladding on the hulls of oceangoing ships. Because it had zinc, it was significantly cheaper than pure copper and still would protect the wood hulls from teredo shipworms. Muntz metal was also much stronger than copper, and the zinc lowered the melting point to 904°C from 1085°C for copper.
Zinc is a metal that has been in and out of art and architecture over the years. Since its discovery, or more so, since the time when casting and rolling into sheets, zinc has found use in architecture. The skyline of Paris is a testimony to the beauty and durability of the metal. Napoleon, around 1805 instructed the chemist Jean-Jacques Dony to develop the rich mines of zinc ore in the Vielle-Montagne. Dony developed a method of refining the ore using a horizontal distilling process that involved a series of retorts set into a furnace. The ore would be roasted, and the zinc fumes would be released and condensate, forming molten zinc. Figure 1.8 is a diagrammatic representation of the retort process.
FIGURE 1.8 Diagram of a Horizontal Retort.
Source: Developed by Dony.
Dony set these retorts in series within a furnace and required a vast amount of heat energy. The process remained in use until the first half of the twentieth century. First, the reaction required the temperature within the retort to reach 1100°C or greater for the chemical reaction to occur between ZnO and carbon. The carbon was introduced from the charcoal, which would burn, creating carbon dioxide gas. Further heat would be applied to vaporize the zinc. Zinc oxide would form as a vapor, and when it combined with the heated carbon, the oxygen would be stripped away and vent out as carbon dioxide. The zinc would be condensing on the cooler portion of the retort and collect along the bottom as liquid metal.
These retorts would be set into arrays and charged with ore and charcoal.
With this new source of the metal, rolling into sheets and plates was possible using rolling techniques perfected with copper and iron plates. The first zinc-rolling mill for sheets of zinc was developed by Dony in 1812, making this metal available as an architectural cladding material to compete with copper and tin-plated steel.
Zinc has a long history in art and architecture. Its use as an alloy metal with copper to make brass was well understood by the Romans and Egyptians, who were attracted by the allure of the golden color the addition of the mineral calamine made with copper. At least they understood that something in the ore would interact with copper and produce brass. Zinc as a metal was unknown to early civilizations because it could not be separated from its ore as other metals. When copper, lead, tin, or iron ore were heated the metal would fall to the bottom of the furnace but zinc would boil and turn to vapor.
In China and in India, early metalworkers found ways of isolating zinc by roasting the ores in crucibles with charcoal and then allowing them to cool. Zinc would separate in small lumps where it could be collected and remelted.
FIGURE 1.9 An example of modern Bidriware made from zinc.
In the fourteenth century, there was an artform called Bidri that used hammered copper and zinc forms with incredible inlay artwork. Figure 1.9 is a modern example of the artwork. Bidri is a product that originated in south central India and is attributed to the Bahamani sultans in the fort city of Bidar. They used the process of engraving and repossé to produce elaborate designs in metal bowls and plates as well as the bases of hookahs.
They would often inlay other metals such as silver or gold and then darken the background metal with sulfide compounds and polish off the top sections.
This area of India is still a major center for manufacturing unique metal work. Today, brass, copper, and zinc are still handcrafted here in the old tradition. It is important to note, these incredible art pieces were created from zinc–copper alloys, where the zinc was 4 times the amount of copper in the base metal to as much as 16 times. Zinc was being produced in large quantities in India as early as the fourteenth century.
There was no known process of producing zinc in Europe until several centuries later. In 1982, an archeological study of the mines in the region around Zawar in Rajasthan was undertaken by a British-Indian research group. They found intact furnaces and clay retorts that indicated smelting of zinc on a significant scale had been underway centuries ago5. The clay retorts were positioned at an angle. The neck-down area was lower than the enlarged section and positioned through a wall of clay and stone into a cooler chamber – much the same way as William Champion and Jean-Jacques Dony arranged their retorts to capture zinc vapor and condense it to create a pure form of zinc. William Champion traveled often to India, and apparently he studied the Indian process and brought it back to England.
Other examples of zinc used in the far Eastern cultures predate the arrival of the metal to Europe. Zinc was rarer than copper and iron in these early times, and the utility of the metal was not yet understood until larger quantities could be produced.
In Europe, once more intense refinement of the metal took form and quantities of the metal became available, artists and artisan began to understand certain beneficial characteristics. One was the low melting temperature, much lower than copper or iron. Once melted, it had good fluidity and could be poured into simpler molds and achieve good detail.
Zinc-cast statues date back to the mid- to late-1700s in Europe, where it was extensively promoted for use in northern Europe. In Prussia, it was used on buildings and ornament for the new capital city of Berlin. Karl Friedrich Schinkel, the architect, artist, and city planner pushed for its use in statuary and building ornamentation in the early 1800s, where the silvery blue metal was used to adorn the new Prussian capital.
In Paris, one has to marvel at the silvery roofs and ornamentation that distinguishes that city. The Baron Hausmann, Prefect of the Seine Department of France under Napoleon III, undertook a vast redevelopment of the famous city in the mid-1800s. This started the cladding of the famous mansards of Paris. Supposedly, the Baron Hausmann had a relative in the zinc-mining business. It could also have been that Hausmann wanted to have a crème colored stone used for the walls of his building design and the use of copper may have led to staining. One of the great benefits of zinc is that its oxides do not stain adjacent materials.
One of the main sources of zinc was the mine, La Vielle Montagne in Kelmis, called La Calamine in French. This area, on the border of Germany was the source for much of the zinc used France at the time of this adornment and reconstruction of Paris. La Vielle Montagne started in the 1400s as a source for zinc used in manufacturing brass. The La Vielle Montagne Zin Mining Company was formed to supply Paris with the zinc needed to redevelop the city under Hausmann. The company became VM Zinc and is one of the largest suppliers of zinc in the world.
The zinc mines around Vielle-Montagne, had been in use since Roman times and this readily available ore was ideal for making a statement for France. As early as 1815, some of the first roofs of Paris were being clad in this silvery metal, zinc, and today close to 90% of the roofs of the great city are still covered in zinc. UNESCO, the United Nations Education, Scientific and Cultural Organization is considering making the zinc roofs of Paris a World Heritage.
The Prussian source of zinc was the area known as Silesia. Silesia, a region in present-day Poland, produced zinc that was known for its low sulfur. Very extensive manufacturing of zinc products took place in this region. The central part of Europe mined and produced much of the zinc used in the world during the 1800s.
It was soon discovered that coating iron in molten zinc would provide galvanic protection to the iron and later steel. By 1830, coating iron with zinc was in wide use throughout Europe. Later that century, steel was invented and overtook iron as a building material. As the less corrosion resistant steel came into major use the later part of the century, coating steel with molten zinc as a sacrificial layer became a major enterprise that continues today. The vast majority of zinc used today is to protect steel by hot dipping in baths of molten zinc.
