UNITED STATES DEPARTMENT OF AGRICULTURE 
DEPARTMENT BULLETIN No. 1500 
Washington, D. C. 
June, 1929 
THE GLUING OF WOOD 
By T. R. Tetjax, Senior Wood Technologist. Forest Products Laboratory, Branch 
of Research, Forest Service 1 
CONTENTS 
Introduction 1 
Glues used in woodworking 2 
Considerations applicable to all uses 4 
Properties important in special cases 4 
Animal glues 5 
Liquid glues 6 
Casein and vegetable-protein glues 6 
Vegetable glues 8 
Blood-albumin slues 9 
Glue tests 9 
Preparation of glues for use 10 
Preparing animal glues 10 
Preparing vegetable glues 12 
Preparing casein glues 13 
Preparing blood-albumin glues 14 
Preparation of wood for gluing 14 
Drying and conditioning. _ 14 
Machining lumber 16 
Preparation of veneer for gluing 19 
The gluing operation 23 
Spreading glue 23 
Pressing and clamping 24 
Drying and conditioning glued j oints 29 
Conditioning glued thick stock 31 
Drying plywood 31 
Page 
Control of gluing conditions 32 
Correlation of pressure and glue con- 
sistency 33 
Gluing end-grain wood 42 
Laying figured veneer 42 
Gluing characteristics of different woods 42 
Relation of density of wood to gluing 
properties 44 
Treating the wood before gluing 48 
Gluing plywood of different species 49 
Tendency of woods to be stained by glue. 49 
Gluing recommendations for different 
species and glues 50 
Principles of glued -wood construction 52 
Cross-banded construction 52 
Parallel-grain construction 56 
Butt-joint construction 59 
Correcting gluing defects _ 60 
Key to causes of gluing defects 60 
Appendix 62 
Glueformulas " 62 
Testing glues 64 
Calculation of pressure on joints 73 
Literature cited 75 
INTRODUCTION 
The use of glue in the fabrication of wood products brings about 
more complete utilization of timber through the use of lower grades, 
inferior species, and small sizes of material; it conserves supplies of 
clear material and of the scarcer and more valuable woods; and it 
makes possible a saving of material in the production of articles of 
unusual form, dimensions, and properties. Nearly every article of 
glued-wood construction represents an economy in the use of timber 
resources. 
The purpose of this publication is to bring together essential infor- 
mation about glues and gluing, to set forth important principles of 
Acknowledgment is made to George M. Hunt, in charge of section of wood preservation, 
and to various other members of the Forest Products Laboratory, for assistance in the 
preparation of this bulletin. Further acknowledgment is made to the University of 
Wisconsin. 
31595°— 29 1 1 
