The advent of synthetic adhesives has transformed the structural applications of wood. However, a persistent issue in adhesively-bonded wood products has been moisture durability. When designing wood based composites, moisture durability will depend on both the wood phase and the adhesive phase. A key question, therefore, is how does one...
The breaking radii of variously discolored veneers of six different hardwood species were small enough, for most of the discolorations, to indicate that such veneers can be used successfully on members having curved surfaces. When expressed in terms of the minimum radius of curvature attained without fracturing, the breaking radius...
Southern pine and Douglas fir veneer samples were dried in air
under the following conditions: air temperatures were 350, 600, and
750°F; air velocities were 50, 100, and 150 feet per second, and
angles of impingement of air against the veneer surfaces were 0°,
45°, and 90°. The resulting drying...
This study was undertaken to determine whether Douglas-fir (Pseudotsuga
menziesii (Mirb.) Franco) veneer could be platen-dried and then
sucessfully glued into two-ply parallel-laminated panels.
A range of veneer thicknesses, platen temperatures and final dry
moisture contents were examined. Thicknesses included were nominal
0.1, 0.2, 0.3 and 0.4 inches; platen temperatures...
Using Southeast Asian hardwood veneers for exterior plywood siding
has caused problems because some species produced quality plywood while
other species produced plywood which delaminated soon after being put
in service in exterior exposure. This study attempted to improve the
durability of glue bonds of some Southeast Asian hardwood veneers...
A new carbohydrate-phenol based resorcinol resin
(CPR resin) was synthesized by end capping a known
carbohydrate-phenol based resole with resorcinol under
basic reaction conditions. Synthetic parameters, such as
duration of cook, pH, and the amount of resorcinol and
formaldehyde were varied to produce resins with molecular
weights (Mw) ranging from...
Eighteen Ponderosa Pine (Pinus ponderosa Dougl.ex.laws) veneer flitches
were randomly selected and crosscut into paired flitches. Serpentine-end-matched
(SEM) joints were machined in the flitches, joint amplitude equal to the width in
one half of the paired flitch and joint amplitude equal to 2/3 width in the other half
of the...
The goal of this research is to develop automatic techniques for
identifying defects in Douglas-fir veneer. To achieve this goal,
computer vision techniques, in particular image-processing, will be
applied. Several pre-processing steps may be required to enhance
images in making further analysis easier, faster, and more reliable.
Pre-processing is often...
Short-term heating of softwood veneer blocks temporarily softens the wood so that it can be peeled more readily. Heating reduces the depth of lathe checks and the likelihood of splitting and thereby increases the quality and quantity of veneer recovered. The softwood-plywood industry conventionally conditions blocks three ways: steaming blocks...
The dynamics of radio frequency (RF) laminated veneer lumber (LVL) pressing are explored for the purpose of optimizing this process. The RF LVL press at the Albany Trus Joist plant is the focus of this investigation. The investigation first focuses on bond strength development characteristics of the Georgia Pacific adhesive...
Past research and industrial sources have implied that preheating Douglas-fir Pseudotsuga menziesii (Mirb.) Franco prior to peeling veneer was economically feasible. To test this, the effect of treatment temperature on veneer yield and thickness variation for three diameter classes of low grade Douglas-fir logs was studied and related to the...
This report is one of a series issued in cooperation with Army Air Forces and the Bureau of Aeronautics under the supervision of the Aeronautical Board. Information reviewed and reaffirmed June 1959.
The drying of wood is required in most forest products
manufacturing operations. Depending on the wood species,
dimensions, drying temperatures, and drying duration, the
amount of emissions and energy consumption can greatly affect
the operating cost, environment, and quality of wood dried.
As such, the forest products industry continues to...
American beech (Fagus grandiflora) is now, and probably will be, increasingly used to replace yellow birch for aircraft construction. Even though it is one of the principal components of the northern hardwood forests of North America, study of the characteristics and properties of its wood has been neglected to the...
Machine vision is widely used in scientific areas and non-wood using
industries, but the extreme variability of wood has limited its adoption by forest
products industries. However, it is now becoming a key factor in further automation
of the forest products industry. As a very important part of machine vision,...
Western juniper and cinnamon essential oils were combined with ethanol at 2.5, 5, and 10% concentrations by weight and applied to hybrid poplar (Populus trichocarpa x P. deltoids) veneers by vacuum soaking to produce a naturally durable wood veneer with increased mechanical properties for use in structural composites. Half of...
Non-destructive commercial ultrasonic grading provides laminated veneer lumber (LVL) manufacturers a means for sorting veneer based on average ultrasonic propagation time (UPT) and/or average dynamic modulus of elasticity (MOEd). While this may provide reliable estimations of modulus of elasticity (MOE), little is known about the influence of veneer defects on...
Face checking in decorative maple veneered plywood panels is a significant
problem for hardwood plywood manufacturers, furniture makers, cabinetmakers, and consumers. Efforts made by panel producers and researchers to minimize checking conducted to-‐date have been limited, and produced contradictory results. In this study the impact of four manufacturing factors believed...
Current lathe technology, smaller diameter logs, smaller core diameters, and
the sale of higher grade veneer for use in engineered wood products are all factors
contributing to plywood manufacturers using rougher veneer with different lathe
check characteristics. When rough veneer is encountered, plywood manufacturers
typically increase the adhesive spread rate...
The objective of this study is to complete life cycle inventories (LCI) for laminated veneer lumber (LVL) and composite I-joist (I-joist) production in the two main forest products producing regions in the U.S., the Pacific Northwest (PNW) and Southeast (SE). LVL and I-joists are composite wood building materials that are...
This report is one of a series issued in cooperation with the Army-Navy-Civil Committee on aircraft design criteria under the supervision of the aeronautical board. Information reviewed and reaffirmed 1962. Original material published 1944.