COPYRIGHT, 1917, BY
D. VAN NOSTRAND COMPANY
THE·PLIMPTON·PRESS
NORWOOD·MASS·U·S·A
PREFACE
The seasoning and kiln-drying of wood is such an important process in the manufacture of woods that a need for fuller information regarding it, based upon scientific study of the behavior of various species at different mechanical temperatures, and under different drying processes is keenly felt. Everyone connected with the woodworking industry, or its use in manufactured products, is well aware of the difficulties encountered in properly seasoning or removing the moisture content without injury to the timber, and of its susceptibility to atmospheric conditions after it has been thoroughly seasoned. There is perhaps no material or substance that gives up its moisture with more resistance than wood does. It vigorously defies the efforts of human ingenuity to take away from it, without injury or destruction, that with which nature has so generously supplied it.
In the past but little has been known of this matter further than the fact that wood contained moisture which had to be removed before the wood could be made use of for commercial purposes. Within recent years, however, considerable interest has been awakened among wood-users in the operation of kiln-drying. The losses occasioned in air-drying and improper kiln-drying, and the necessity for getting the material dry as quickly as possible after it has come from the saw, in order to prepare it for manufacturing purposes, are bringing about a realization of the importance of a technical knowledge of the subject.
Since this particular subject has never before been represented by any technical work, and appears to have been neglected, it is hoped that the trade will appreciate the endeavor in bringing this book before them, as well as the difficulties encountered in compiling it, as it is the first of its kind in existence. The author trusts that his efforts will present some information that may be applied with advantage, or serve at least as a matter of consideration or investigation.
In every case the aim has been to give the facts, and wherever a machine or appliance has been illustrated or commented upon, or the name of the maker has been mentioned, it has not been with the intention either of recommending or disparaging his or their work, but has been made use of merely to illustrate the text.
The preparation of the following pages has been a work of pleasure to the author. If they prove beneficial and of service to his fellow-workmen he will have been amply repaid.
THE AUTHOR.
September, 1917
CONTENTS
| Section I | |
| TIMBER | PAGES |
| Characteristics and Properties of Same—Structure of Wood—Properties of Wood—Classes of Trees | 1-7 |
| Section II | |
| CONIFEROUS TREES | |
| Wood of Coniferous Trees—Bark and Pith—Sapwood and Heartwood—The Annual or Yearly Ring—Spring- and Summer-Wood—Anatomical Structure—List of Important Coniferous Trees | 8-30 |
| Section III | |
| BROAD-LEAVED TREES | |
| Wood of Broad-leaved Trees—Minute Structure—List of Most Important Broad-leaved Trees—Red Gum—Range of Red Gum—Form of Red Gum—Tolerance of Red Gum—Its Demands upon Soil and Moisture—Reproduction of Red Gum—Second-growth Red Gum—Tupelo Gum—Uses of Tupelo Gum—Range of Tupelo Gum | 31-85 |
| Section IV | |
| GRAIN, COLOR, ODOR, WEIGHT, AND FIGURE IN WOOD | |
| Different Grains of Wood—Color and Odor of Wood—Weight of Wood—Weight of Kiln-dried Wood of Different Species—Figure in Wood | 86-97 |
| Section V | |
| ENEMIES OF WOOD | |
| General Remarks—Ambrosia or Timber Beetles—Round-headed Borers—Flat-headed Borers—Timber Worms—Powder Post Borers—Conditions Favorable for Insect Injury—Crude Products—Round Timber with Bark on—How to Prevent Injury—Saplings—Stave, Heading, and Shingle Bolts—Unseasoned Products in the Rough—Seasoned Products in the Rough—Dry Cooperage Stock and Wooden Truss Hoops—Staves and Heads of Barrels Containing Alcoholic Liquids | 98-113 |
| Section VI | |
| WATER IN WOOD | |
| Distribution of Water in Wood—Seasonal Distribution of Water in Wood—Composition of Sap—Effects of Moisture on Wood—The Fibre-Saturation Point in Wood | 114-118 |
| Section VII | |
| WHAT SEASONING IS | |
| What Seasoning Is—Difference Between Seasoned and Unseasoned Wood—Manner of Evaporation of Water—Absorption of Water by Dry Wood—Rapidity of Evaporation—Physical Properties that Influence Drying | 119-127 |
| Section VIII | |
| ADVANTAGES OF SEASONING | |
| Advantages of Seasoning—Prevention of Checking and Splitting—Shrinkage of Wood—Expansion of Wood—Elimination of Stain and Mildew | 128-137 |
| Section IX | |
| DIFFICULTIES OF DRYING WOOD | |
| Difficulties of Drying Wood—Changes Rendering Drying Difficult—Losses Due to Improper Kiln-drying—Properties of Wood that Effect Drying—Unsolved Problems in Kiln-drying | 138-144 |
| Section X | |
| HOW WOOD IS SEASONED | |
| Methods of Drying—Drying at Atmospheric Pressure—Drying Under Pressure and Vacuum—Impregnation Methods—Preliminary Treatments—Out-of-door Seasoning | 145-155 |
| Section XI | |
| KILN-DRYING OF WOOD | |
| Advantages of Kiln-drying over Air Drying—Physical Conditions Governing the Drying of Wood—Theory of Kiln-drying—Requirements in a Satisfactory Dry Kiln—Kiln-drying—Remarks—Underlying Principles—Objects of Kiln-drying—Conditions of Success—Different Treatments According to Kind—Temperature Depends—Air Circulation—Humidity—Kiln-drying—Pounds of Water Lost in Drying 100 Pounds of Green Wood in the Kiln—Kiln-drying Gum—Preliminary Steaming—Final Steaming—Kiln-drying of Green Red Gum | 156-184 |
| Section XII | |
| TYPES OF DRY KILNS | |
| Different types of Dry Kilns—The "Blower" or "Hot Blast" Dry Kiln—Operating the "Blower" or "Hot Blast" Dry Kiln—The "Pipe" or "Moist-Air" Dry Kiln—Operating the "Pipe" or "Moist-Air" Dry Kiln—Choice of Drying Method—Kilns of Different Types—The "Progressive" Dry Kiln—The "Apartment" Dry Kiln—The "Pocket" Dry Kiln—The "Tower" Dry Kiln—The "Box" Dry Kiln | 185-205 |
| Section XIII | |
| DRY KILN SPECIALTIES | |
| Kiln Cars and Method of Loading Same—The "Cross-wise" Piling Method—The "End-wise" Piling Method—The "Edge-wise" Piling Method—The Automatic Lumber Stacker—The Unstacker Car—Stave Piling—Shingle Piling—Stave Bolt Trucks—Different Types of Kiln Cars—Different Types of Transfer Cars—Dry Kiln Doors—Different Types of Kiln Door Carriers | 206-236 |
| Section XIV | |
| HELPFUL APPLIANCES IN KILN DRYING | |
| The Humidity Diagram—Examples of Use—The Hygrodeik—The Recording Hygrometer—The Registering Hygrometer—The Recording Thermometer—The Registering Thermometer—The Recording Steam Gauge—The Troemroid Scalometer—Test Samples—Weighing—Examples of Use—Records of Moisture Content—Saw Mills—Factories—The Electric Heater | 237-250 |
| Section XV | |
| Bibliography—Glossary—Index of Latin Names—Index of Common Names | 251-257 |
LIST OF ILLUSTRATIONS
