Zinc Surfaces

L. WILLIAM ZAHNER is President and CEO of A. Zahner Company, Inc. and Zahner Metal Conservation. He is an internationally recognized expert on the design and use of architectural metals, and the author of this series of books, including Stainless Steel Surfaces; Aluminum Surfaces; Steel Surfaces; and Copper, Brass, and Bronze Surfaces, all published by Wiley.

• Preface xiiiChapter 1 Introduction to Zinc 1Element 30 Zn – Spelter 1The Zinc Atom 9History 11Zinc Mineral Forms 17Zinc in Art 18Zinc as an Architectural Metal 24Health and Hygiene 28The Enigmatic Metal 31Chapter 2 Zinc Alloys 33Introduction 33Alloying Descriptions 34Ingot Alloys 36Zinc Alloys – Rolled Forms 39Zinc Alloys Used in Architecture 41Wrought Zinc Alloys 44Architectural Rolled Zinc 47Forged and Extruded Zinc Alloys 53Cast Zinc Alloys 55Slush Casting 56Zinc Die Casting 58Gravity Cast Alloys 59Kirksite 62Chapter 3 Finishes 63Introduction 63Appearance among Metals 65Mill Finishes 68Natural Zinc Color 68Mechanical Finishes 71Mechanically Rolled Textures 72Preweathered Zinc Surface 73Clear Coating with Pigmentation 77Blackened Zinc 77Custom Patina Finish 79Dark Variegated Patinas on Zinc 80Zinc Oxide Patinas 87Zinc Iridescent Patina 93Galvanized Zinc Surfaces 93Galvanized Steel Structural Shapes 99Darkening Galvanized Steel 100Zinc Phosphate Coatings on Galvanized Steel 101Zinc Fabric 102Other Methods of Applying Zinc to Steel 103Zinc Anodizing 104Chapter 4 Expectations 105Introduction 105Natural Finish on Thin Sheet Material 107Natural Finish on Thick Plate Material 109Natural Finish on Cast Surface 110Preweathered Finish 113Preweathered with Added Pigmentation 119Expectations – Preweathered Surface 120Blackened Zinc 121Color Matching 122Custom Patinas 124Flatness and Visual Distortion 131Creep 135Galvanized Surface 138Darkened Galvanized Steel 142Chapter 5 Available Forms 145Introduction 145Wrought Forms of Zinc 148Plate 152Sheet and Coil 153Zinc Foil 158Extrusion 158Tube and Pipe 159Wire 160Rod 160Wire Mesh 160Expanded Metal 160Perforated Zinc 162Textured Zinc Sheet 163Zinc Ornamentation 165Cast 166Slush Cast 167Die Cast 167Sand Cast 169Zinc Powder 171Chapter 6 Fabrication 173Working with Zinc 173Storage and Handling 174Cutting Zinc 177Shearing and Blanking 177Saw Cutting 177Laser 178Plasma 179Waterjet 179Punching / Perforating / Bumping 180Forming and Bending 184Grain Direction and Anisotropy 185Temperature Effect on Forming 187Brake Forming 187V-Cutting 191Roll Forming 191Superplastic Forming 192Forging 193Extrusion 194Machining 194Soldering 195Welding 197Fusion Stud Welding 199Resistant Welding of Zinc 201Expansion / Contraction 202Bolting and Fastening 204Thermal Spray 206Hot-Dipped Galvanizing 206Casting 208Die Casting 210Slush Casting 211Permanent Mold Casting 212Sand Casting 212Plaster Mold Casting 212Spin Casting 212Chapter 7 Corrosion 215Introduction 215Zinc as a Protective Coating 216Galvanized Steel 218Zinc Alloy Coatings on Steel 219Zinc Powder in Paint Coatings 220Sherardizing 221Thermal Spray 221Zinc Anodes 222Battery 222When Zinc Does Not Protect Steel 224Zinc Corrosion 225Interior Exposures 227Exterior Exposures 228Sheltered Exterior Surfaces 230Uniform Corrosion 235Underside Corrosion 236Wet Storage Stain 237Galvanic Corrosion 239Determining Factors for Galvanic Corrosion 242Difference in Electro-Potential 243Geometric Relationship 243Distance 244Electrolyte Effects 244Temperature Effects 245Pitting Corrosion 246Intergranular Corrosion 248Stress Corrosion Cracking 248Zinc Artifacts and Statues 249Deicing Salts 251Chlorides 252Fertilizer 253Saponification 254Corrosive Substances in Proximity 254Chapter 8 Maintaining the Zinc Surface 257Introduction 257Zinc Surfaces 258Why a Maintenance Procedure 260Develop a Maintenance Strategy 260Restoring the Preweathered Appearance 264Effects of Different Environments 266Physical Cleanliness 267Chemical Cleanliness 278Mechanical Cleanliness 292Galvanized Steel Surfaces 296Appendix A Brand Names 301Appendix B Select Specifications for Zinc 303References 305Index 307