Veneer laminate composite structure

A method of forming a wood sandwich structure comprising the steps of peeling a bolt of natural wood in spiral form to form a web of wood veneer; forming the wood veneer web into a plurality of sheets of uniform size; forming a plurality of fiberglass sheets having a size corresponding to the size of the wood veneer sheets; and bonding alternate sheets of wood veneer and fiberglass together with a resin to form a remanufactured wood composite sandwich structure comprising alternate sheets of wood veneer and fiberglass bonded together by the resin. Also disclosed is a specific wood sandwich structure for use in boat building; another specific wood sandwich structure especially suitable for use in furniture building; a method of forming a boat hull utilizing a wood sandwich structure according to the invention; and a method of forming furniture utilizing a wood sandwich structure according to the invention.

BACKGROUND OF THE INVENTION 
This application relates to composite structures and, more particularly, to 
a composite or sandwich structure employing sheets of wood veneer. 
At one time wood accounted for the vast majority of manmade structures. 
Gradually, however, wood has fallen out of favor in many market areas 
because of the high maintenance costs and short structure life resulting 
from rot, paint peeling, instability, swelling and warping. For example, 
with respect to boats, metals and fiberglass constructions have gradually 
accounted for the vast majority of boats of every size and description and 
wood, conversely, has been relegated to use in selected custom 
applications where initial labor costs and/or maintenance are not 
controlling factors. However, wood in most respects is an excellent 
building material due to its stiffness, light weight and fatigue 
resistance. It's shortcomings are primarily moisture related and these 
shortcomings are, of course, exacerbated when applied in areas such as the 
boat building art. 
SUMMARY OF THE INVENTION 
The present invention concerns a wood veneer laminate composite structure 
which substantially eliminates the inherent rotting, swelling and warping 
problems that have traditionally plagued wooden structures while improving 
upon the inherent structural advantages of wood and retaining the 
attractive wood appearance. 
According to one aspect of the invention, a sheet of processed material is 
sandwiched between two sheets of wood veneer and resin is interposed 
between the sheets of the sandwich to firmly bond the sheets together and 
form a laminate composite structure which presents a natural wood 
appearance on both exterior surfaces but which, by virtue of the 
interposed layer of processed material and the overall sealing and binding 
action of the resin, is structurally superior to natural wood and 
significantly more resistant to the moisture problems that plague natural 
wood. The sheet of processed material is preferably fibrous in structure, 
such for example as fiberglass, and serves to synergistically compliment 
the sheets of wood veneer. Specifically, the cables or strands of the 
sheet of fibrous material provide a reinforcing skeleton for the composite 
structure and provide tensile strength for the composite structure, and 
the sheets of wood veneer encage or encapsulate the strands of the fibrous 
sheet to discourage failure of the strands in compression and provide 
compressive strength for the composite structure. Tests on the composite 
structure of the invention, using standardized test procedures for 
sandwich constructions, conclusively establish that the invention sandwich 
structure is significantly stronger than comparable wood or wood veneer 
structures or comparable fibrous or fibrous veneer structures. 
According to a further aspect of the invention, a method of forming a 
remanufactured wood sandwich structure is disclosed comprising the steps 
of peeling a bolt of natural wood in spiral form to form a web of wood 
veneer; forming the wood veneer web into a plurality of sheets of uniform 
size; forming a plurality of other sheets, each formed of a material 
dissimilar to the wood veneer sheets and each having a size corresponding 
to the size of the wood veneer sheets; and intermixing the wood veneer 
sheets and the other sheets while interposing resin between the intermixed 
sheets to form an intermixed stack of sheets with resin interposed between 
the sheets; and curing the resin to form a remanufactured wood sandwich 
structure comprising intermixed sheets of wood veneer and other dissimilar 
sheets bonded together by the resin. This method utilizes all of the wood 
available in a natural tree trunk, avoiding the high scrappage inherent 
when the trunks are cut into planks, and provides a material that is 
superior to natural wood as an engineering structure, that retains the 
appearance advantages of natural wood, and that is substantially free of 
the rotting, swelling and warping problems that have typically plagued 
wooden structures. 
According to a further aspect of the invention, a specific wood sandwich 
structure is disclosed which is especially suitable for use in high 
moisture environments such as boat building. The wood sandwich structure 
according to this aspect of the invention includes a sheet of core 
material having a grain strength running generally normal to the plane of 
the sheet; a sheet of processed material resin bonded to the sheet of core 
material; a first sheet of wood veneer resin bonded to the sheet of 
processed material; and a second sheet of wood veneer resin bonded to the 
first sheet of wood veneer with its grain crossing with respect to the 
grain of the first sheet of wood veneer. This construction provides grain 
strength in the X, Y and Z direction as provided respectively by one of 
the wood veneer sheets, the other of the wood veneer sheets, and the sheet 
of core material. The sheet of processed material adds tensile or cable 
strength and rigidity to the overall structure. This sandwich structure is 
specially suited for use in boat building wherein the layers are arranged 
such that the sheet of end core material is on the inside of the boat and 
the layers of wood veneer are on the outside of the boat so as to provide 
a rigid and moisture resistant boat hull while preserving the attractive 
and sought after wood look for the boat hull. 
According to a further aspect of the invention, a wood sandwich structure 
is disclosed which is especially suited for forming concavo-convex 
structures. According to this aspect of the invention, which is 
particularly suitable for forming a boat hull for example, a sheet of wood 
veneer is formed into a concavo-convex configuration; a layer of resin is 
applied to the concave interior surface of the wood veneer sheet; a sheet 
of processed material is conformed to the concave inner surface of the 
wood veneer sheet; and the sheets are bonded together to form a laminated 
concavo-convex structure with the wood sheet forming the exterior of the 
structure to provide a wooden appearance to the structure and the sheet of 
processed material forming the concave interior of the structure and 
reinforcing the wood sheet to form, together with the wood sheet, an 
attractive and yet extremely strong concavo-convex structure. 
According to a further aspect of the invention, a wood sandwich structure 
is provided which is especially suitable for use in building trades such 
as furniture construction. The wood sandwich structure according to this 
aspect of the invention includes a central sheet of core material having a 
grain running generally normal to the plane of the sheet; a sheet of 
processed material resin bonded to each face of the sheet of core 
material; and a sheet of wood veneer resin bonded to the exposed face of 
each sheet of processed material. This arrangement provides a wood 
sandwich structure which is totally symmetrical and therefore extremely 
resistant to warpage; which has high strength and rigidity and high 
moisture resistance; and which is otherwise especially suited for use in 
the furniture manufacturing business. In the disclosed embodiment of this 
aspect of the invention, the wood sandwich structure further includes a 
second sheet of wood veneer resin bonded to the exposed face of each sheet 
of wood veneer with its grain crossing with respect to the grain of the 
sheet of wood veneer to which it is bonded. This arrangement provides X, 
Y, Z strength to the wood sandwich while retaining the symmetry, and 
therefore the warp resistance, of the structure. 
According to a further aspect of the invention, a non-planar article of 
manufacture is formed by forming a wood sandwich structure as disclosed 
into the non-planar configuration of the article of manufacture. For 
example, a desk may be formed according to this aspect of the invention by 
forming the wood sandwich structure into a U configuration with the legs 
of the U comprising the legs of the desk and the bight of the U comprising 
the top of the desk. 
The invention further comprises a method of forming a boat hull utilizing a 
wood sandwich structure according to the invention. The invention boat 
building method comprises forming a mold having a configuration conforming 
to the shape of the desired boat hull; placing a plurality of strakes of a 
wood veneer material adjacent the mold surface with the strakes running 
generally parallel to the center line of the hull and the grain of the 
strakes extending generally in the plane of the strakes; applying a resin 
to the exposed surfaces of the strakes; placing a sheet of wood veneer 
adjacent the strakes with the grain of the sheet extending generally in 
the plane of the sheet but at cross angles with respect to the grain of 
the strakes; applying a resin to the exposed surface of the wood veneer 
sheet; placing a sheet of processed material adjacent the wood veneer 
sheet; applying a resin to the exposed surface of the sheet of processed 
material; placing a sheet of core material adjacent the sheet of processed 
material having a grain strength running in a direction generally normal 
to the plane of the sheets; applying a resin to the exposed surface of the 
sheet of core material; placing a further sheet of processed material 
adjacent the sheet of core material; and pressing the strakes and sheets 
together to bond them to form a boat hull conforming in shape to the shape 
of the mold. The boat hull is then removed from the mold and a coating of 
resin is applied to the exposed surfaces of the strakes to seal those 
surfaces while preserving the natural wood appearance. The invention 
method provides a boat hull having superior stiffness and strength 
characteristics and which retains the appearance and feel of a wooden boat 
while substantially eliminating the maintenance problems that have been 
previously plagued wooden boats. The invention method also allows high 
volume reusable mold techniques to be applied to the construction of wood 
boats, as opposed to the tedious and labor-intensive custom or kit 
techniques previously employed in wooden boat construction. 
In the various disclosed embodiments of the invention, the sheets or 
processed material may comprise sheets of triaxial fiberglass and the 
sheet of core material may comprise a sheet of end grain balsa wood. The 
wood veneer sheets, the balsa core sheet and the triaxial fiberglass 
sheets together provide an extremely strong wood sandwich structure and 
the resin interposed between the various layers adds to the structural 
strength of the sandwich structure, provides firm bonding between the 
various sheets, and provides an effective moisture barrier for the wood so 
that the sandwich structure retains the appearance and stiffness 
advantages of wood while substantially eliminating the moisture related 
problems previously associated with a wood structure. Specifically, and as 
previously discussed, the cables or strands of the fiberglass sheets 
provide a reinforcing skeleton for the composite structure and provide 
tensile strength for the structure, and the sheets of wood encage the 
fiberglass sheets to discourage failure of the cables in compression and 
provide compressive strength for the composite structure.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
The method of remanufacturing wood seen in FIG. 1 comprises the steps of 
peeling a bolt, such as a log 1, of natural wood in spiral form to form a 
web 2 of wood veneer; forming the wood veneer web 2, in a suitable cutting 
operation, into a plurality of sheets 3 of wood veneer; suitably forming a 
plurality of sheets 4 of processed material having a size corresponding to 
the size of the wood veneer sheets 3; and bonding alternate sheets of wood 
veneer 3 and processed material 4 together with a resin 5 to form a wood 
composite sandwich structure comprising alternate sheets of wood veneer 
and processed material bonded together by the resin. 
In its simpliest form, as seen at 6 in FIG. 1A, the remanufactured wood 
composite sandwich structure may comprise a sheet of processed material 4 
sandwiched between two sheets of wood veneer 3 with a resin 5 binding the 
sheets together to provide a composite wood structure 6 which presents a 
natural wood appearance on both exterior surfaces 
In a more complex form, and as seen at 7 in the final step in the method of 
FIG. 1, the remanufactured wood composite sandwich structure may comprises 
alternate layers of wood veneer 3 and processed material 4 bonded together 
by resin 5 to form a multi-ply composite structure with wood veneer sheets 
3 on both exterior surfaces. 
Remanufactured wood sandwich structure 7 is suitable for use in most 
applications where natural wood has heretofore been used, such for example 
as in the manufacture of bowling pins, as seen in FIG. 2, or in the 
manufacture of baseball bats, as seen in FIG. 3. 
The remanufactured wood sandwich structure of the invention, whether in its 
simplest form as represented by structure 6 of FIG. 1A or in its more 
complex form as represented by structure 7 of FIG. 1, retains, and in fact 
improves significantly upon, the appearance, stiffness, light weight, and 
fatigue resistant advantages of natural wood while substantially 
eliminating the inherent rotting, swelling and warping problems that had 
traditionally plagued wooden structures. The remanufactured wood sandwich 
structure of the invention, by virtue of the compressive strength provided 
by the wood veneer sheets, the tensile and reinforcing strength provided 
by the fibers of the sheets of processed material, and the unit strength 
provided by the resin, is stronger in all critical measurable respects 
than natural wood or other sandwich or unitary structures of comparable 
size or weight. The thickness of the wood veneer sheets and processed 
sheets employed to form the remanufactured wood sandwich structure 6 or 7 
will vary with the intended application. Wood veneer thicknesses of 0.0625 
inches and processed sheet thicknesses of 0.0500 inches have been found to 
produce superior structure for most applications. 
The wood veneer sheets 3 may be formed, for example, from African mahogony. 
The sheets 4 of processed material may take various forms including sheets 
of carbon impregnated glass or sheets of woven nylon fiber. Preferably, 
sheets 4 comprise triaxial fiberglass sheets having fibers oriented at 
0.degree., 45.degree. and 90.degree.. Resin 5 preferably comprises a clear 
liquid epoxy resin specifically designed to wet-out wood fiber. Such a 
resin is available, for example, from Gougeon Brothers, Inc. of Bay City, 
Mich. as WEST SYSTEM 105 Epoxy Resin and WEST SYSTEM 205 Hardener. In the 
invention composite structure, the cables or strands of the sheets of 
fiberglass provide a reinforcing skeleton for the structure and provide 
tensile strength for the structure, and the sheets of wood veneer encage 
or encapsulate the strands of the fiberglass sheets to discourage failure 
of the strands in compression and provide compressive strength for the 
composite structure. The identified resin and hardener fill the voids and 
irregularities in the confronting surfaces of the various sheets and 
effectively lock the sheets together. The resin and hardener also 
penetrate the surfaces of the sheets to a depth of, for example, between 
0.005 and 0.015 inches and thereby add measurably to the overall strength 
of the composite structure. The invention composite thus derives 
reinforcing and tensile strength from the strands or cables of the 
fiberglass, derives compressive strength from the wood veneer sheets, and 
derives overall unity strength from the bonding and penetrating effect of 
the resin. 
FIGS. 4 and 5 show a wood sandwich structure according to the invention 
that is particularly suitable for boat construction. The veneer laminate 
composite structure of FIGS. 4 and 5 include a first sheet of wood veneer 
10, a second sheet of wood veneer 12, a sheet of processed material 14, a 
sheet of core material 16, and a further sheet of processed material 18. A 
resin layer 20 is interposed between each of the sheets to bond the sheets 
together and a coating of resin 22 is applied to the exposed surface of 
wood veneer sheet 10. 
As with the remanufactured wood sandwich structure of FIG. 1, the wood 
veneer sheets 10 and 12 may comprise African mahogany, the sheets of 
processed material 14 and 18 may comprise triaxial fiberglass sheets 
having fibers orientated at 0.degree., 45.degree. and 90.degree., and the 
resin employed for the interposed layers 20 as well as for the finish 
coating 22 may comprise WEST SYSTEM 105 Epoxy Resin and WEST SYSTEM 205 
Hardener. The sheet of core material 26 may take various forms including 
aluminum honeycomb, paper core honeycomb, or any sheet material having a 
primary grain strength running in a direction generally normal to the 
plane of the sheet. Preferably, sheet 16 comprises a sheet of end grain 
balsa wood. 
As seen in FIG. 5, the outer wood veneer sheet 10 may comprise an assembly 
of longitudinal planks or strakes 24 separated by a series of narrow 
strips 26 of any suitable black wood such as black walnut or black ebony. 
The grain of wood veneer strakes 24 preferably extends generally 
lengthwise of the strakes. Wood veneer sheet 12 has a grain extending in 
the plane of the sheet but at cross angles with respect to the grain of 
strakes 24. The primary grain of core sheet 16, whether it comprise the 
preferred end core balsa or a suitable honeycomb material, provides grain 
strength running in a direction generally normal to the plane of sheets 10 
and 12 so that the composite structure provides grain strength in the X, Y 
and Z directions with grain strength in the X direction provided by wood 
veneer sheet 10, grain strength in the Y direction provided by wood veneer 
sheet 12, and grain strength in the Z direction provided by core sheet 16. 
The use of the invention wood sandwich structure in the formation of a boat 
hull is illustrated in FIG. 6. A female mold 28 of fiberglass or the like 
is provided to supply the basic hull configuration. Mold 28 is preferably 
suitable journaled as at 30 so as to allow the mold to be pivoted so that 
hull may be built up in arcuate sections with maximum gravity assist being 
provided for each of the several arcuate sections by selective rotation of 
the mold about pivot 30. For example, and as shown, the boat hull may be 
built up in four equal 45.degree. arcuate sections with the mold being 
tilted after completion of each section to bring the next section into a 
position providing maximum gravity assist. 
To form the boat hull, a plurality of strakes 24 are placed adjacent the 
mold surface with the strakes running generally parallel to the 
longitudinal center line of the hull so that the grain of the strakes 
extends generally parallel to the hull center line. Separation strips 26 
are positioned between adjacent strakes and the strips and strakes may be 
temporarily secured in position against the mold surface by the use of 
double sided masking tape. After the strakes and strips constituting a 
particular arcuate section of the hull have been positioned against the 
mold, epoxy resin is applied to the exposed inner surfaces of the strakes 
and strips whereafter a wood veneer sheet 12 is placed adjacent the 
strakes with the grain of sheet 12 extending generally at cross angles 
with respect to the grain of the strakes. Another layer of resin is now 
applied to the exposed inner surface of sheet 12 and a sheet of fiberglass 
14 is placed adjacent the exposed inner surface of sheet 12. Another layer 
of resin is now applied to the exposed inner surface of fiberglass sheet 
14 and a sheet 16 of end core balsa wood is placed adjacent the exposed 
inner surface of fiberglass sheet 14 with the end grain of the balsa wood 
sheet running in a direction normal to the grain of wood veneer sheet 12 
and normal to the grain of strakes 24. A further layer of resin is now 
applied to the exposed inner surface of end grain balsa wood sheet 16 and 
a further sheet of fiberglass 18 is positioned adjacent the exposed inner 
surface of balsa wood sheet 16. The various sheets are now pressed 
together by the use of weights such as sandbags 32 or the like to allow 
the epoxy to initially cure. 
Alternatively, less than all of the sheets may be pressed together and 
allowed to initially cure, whereafter the remainder of the sheets may be 
applied to the initially cured sheets and pressed together. For example, 
sheets 10, and 12 may be positioned and pressed together and allowed to 
initially cure, whereafter sheets 14, 16 and 18 may be added and pressed 
together. When using the identified epoxy resin and hardener, the initial 
cure, whether of some or all of the sheets, will take approximately 20 
minutes, whereafter the weights may be removed to allow a full cure which 
will occur after 8 to 10 hours. Following the full cure of all of the 
sheets, the boat hull may be removed from the mold 28 and a coating of 
resin 22, formed of the same resin as the resin layers 20 interposed 
between the various sheets, may be applied to the exterior surface of the 
strakes 24 and the strips 26 to provide a moisture seal for this exterior 
surface. Since the identified epoxy resin is clear, the resin seals the 
exterior surface of the hull while preserving the natural wood appearance. 
Alternatively, the boat hull may be formed in the mold consisting of 
sheets 12, 14, 16, and 18 and the strakes 24 and strips 26 may be applied 
to the exposed surface of wood veneer sheet 12 after the hull has been 
removed from the mold. 
If desired, a veil coat 34 of fiberglass cloth may be applied over coating 
22 and a further resin coating 36 applied to the exposed surface of 
fiberglass veil coat 34. Fiberglass cloth 34 may have a thickness of 0.005 
inches and becomes transparent when wetted. Cloth 34 toughens the exterior 
surface of the hull to provide impact resistance and adds overall strength 
to the hull. 
The resulting boat hull is extremely stress resistant in all directions, 
provides a superior stiffness-to-weight ratio and a superior 
strength-to-weight ratio, and preserves the sought after appearance and 
"feel" of a wood hull while substantially eliminating the moisture 
problems inherent in previous wood hull designs. The invention boat hull 
also lends itself to mass production techniques since all of the reusable 
mold techniques that have allowed volume low cost production of fiberglass 
hulls are equally applicable to the construction of the composite wooden 
hull of the invention. 
When used to form a boat hull, the wood sandwich composite structure of 
FIGS. 4-6 may, for example, have an overall thickness of 0.75 inches with 
each wood veneer sheet comprising a thickness of 0.0625 inches, each 
fiberglass sheet comprising a thickness of 0.0500 inches, the end grain 
balsa core sheet having a thickness of 0.4800 inches, and the various 
layers of resin together comprising a thickness of 0.045 inches. These 
thicknesses are of course not critical nor limiting but these particular 
thicknesses have been found to produce a superior structure, especially 
when applied in a boat building environment. 
The invention is seen in FIG. 7 as applied to the formation of 
convavo-convex structures such, for example, as a boat hull. As seen in 
FIG. 7, a sheet of wood veneer 38 may be placed adjacent the inner surface 
of mold 28 whereafter a layer of epoxy resin 40 may be applied to the 
exposed inner surface of the wood veneer sheet 38 whereafter a sheet of 
fiberglass 42 may be placed adjacent the exposed inner surface of wood 
veneer sheet 38 and a suitable curing technique employed to allow the wood 
veneer sheet 38, resin 40 and fiberglass sheet 42 to set up to form a 
rigid, laminate, concavo-convex structure 44. In concavo-convex structure 
44, the wood veneer sheet forms the rounded exterior of the structure to 
provide a wooden appearance to the structure and the fiberglass sheet 
forms the concave interior of the structure and reinforces the wood veneer 
to form, together with the wood sheet, an attractive and yet extremely 
strong concavo-convex structure. 
The wood sandwich structure as seen in FIGS. 8 and 9 is especially suited 
for use in furniture manufacture. The structure of FIGS. 8 and 9 comprises 
a central sheet of end core material 46; a sheet of processed material 48 
resin bonded to each face of core sheet 46; a wood veneer sheet 50 resin 
bonded to each sheet 48 of processed material; and a second wood veneer 
sheet 52 resin bonded to each sheet 50 of wood veneer with the grain of 
each sheet 52 crossing with respect to the grain of the associated sheet 
50. The resulting wood sandwich structure 54, including interposed layers 
of resin 56, has total symmetry and is therefore extremely resistant to 
warpage. Structure 54 also includes the X, Y and Z strength as described 
in connection with the structures of FIGS. 4-6 and synergistically 
combines the tensile strength provided by the strands or cables of the 
processed material, the compressive strength provided by the wood veneer 
sheets and the unity strength provided by the bonding and penetrating 
effects of the resin. Structure 54 in fact is significantly stronger than 
comparable wood or wood veneer structures or comparable processed sheet or 
composite processed sheet structures. 
Structure 54 is seen in FIGS. 9 and 10 employed to form a desk 58. 
Specifically, a single continuous composite strip of wood sandwich 
structure 54 is suitably formed into a U configuration with the legs of 
the U comprising the legs 54a of the desk and the bight of the U 
comprising the top 54b of the desk. Wood sandwich structure 54 is 
especially well suited for furniture application because of its extreme 
resistance to warpage, excellent stiffness and overall strength, and 
extreme resistance to any of the moisture problems that have traditionally 
plagued natural wood structures. Central core member 46 preferably 
comprises a sheet of end core balsa; processed sheets 48 preferably 
comprise sheets of triaxial fiberglass; sheets 50 and 52 preferably 
comprise sheets of a hardwood such as cherry or oak; and resin 56 
preferably comprises WEST SYSTEM 105 Epoxy Resin and WEST SYSTEM 205 
Hardener. 
Although preferred embodiments of the invention have been illustrated and 
described in detail, it will be apparent that various changes may be made 
in the disclosed embodiments without departing from the scope or spirit of 
the invention.