Constructional and other Wood Work.
Year: 1885

page_text: Constructional and other Wood Work.
I, GEORGE JOHN TAGG, of the firm of T. G. Tagg & Son, of the Island Boat
Building Works, East Moulsey, in the County of Surrey, Boat & Steam Launch
Builder, do hereby declare the nature of this invention and in what manner the
same is to be performed, to be particularly described and ascertained in and by the
following statement:-
In my specification, N° 14212, of 1884, I describe an improved method of making
a scam between two boat planks, and my present invention is an extension of the
one protected by Letters Patent N° 14212 of 1884.
According to my present invention, the material of the joint may be cotton,
flax, silk, or equivalent material, and either spun or woven, or a combination of
spun and woven materials may be used.
In my specification above mentioned I pointed out the necessity of preparing the
woven material of the seam by soaking it in a solution of red-lead, varnish, and
waste paint, or in copal varnish, the object of this soaking being to make the seam
elastic and damp-proof.
Now, according to my present invention, I discard red leads and paints, and
use the dregs, or settlings, from barrels of any foreign vegetable gums. This I
have found to be an excellent material for the purpose of my invention, which may
be described generally as an improved method of making air and water-tight joints
between the butt or lapped edges of two adjoining planks or boards, and is
applicable in all constructional wood, or other, work, where it is necessary to make
a butt or lapped joint between two planks, boards, or pieces of wood, or other
material, which shall be capable of successfully resisting the influence of damp, or
of heat, or of any atmospheric change likely to produce contraction or expansion
of the joint.
It is a well-known fact, that, when two boards are laid edge to edge, e.g., in the
case of a ship's deck; or of the floor of a room, or a verandah; or of a boarded
partition, or wall of a cabin; a rise in temperature will dry up the boards, thereby
contracting them, and causing the joints to open; and that, during a subsequent
term of wet weather, the boards will not only swell out again, sufficiently to make
the joints tight, but may expand to a sufficient extent to make them partially drag
themselves away from the nails, or screws, used to fasten them to the cross beams,
or joists, or the like...

page_text: The experience of caulked seams, as practiced in boat-building, has been repeated
whenever a butt joint, caulked in the same way as the seams of a boat, has been
exposed to considerable atinospheric changes.
This being the case, it is evident that for the production of a perfect joint in
constructional wood-work, it is essential to employ a material that will not be
deleteriously affected, much less destroyed-by the maximum compression to
which it may be subjected by the expansion of the boards, or pieces, between which
it is laid, and still be endowed with sufficient natural elasticity to follow the
separating edges of the boards, as the latter contract under the influence of heat,
without either being torn, or cracked, or wrenched away from its hold on the edges
of the boards.
The accompanying figures illustrate the application of my invention to making
a joint between the edges of two long boards, of the same thickness, laid edge to
edge, although I would have it distinctly understood that my improved joint may
be advantageously used in constructional wood-work, whenever it is required to
make a butt, or lap, joint capable of resisting the influences of considerable
atmospheric changes, and is not limited by the relative dimensions of the adjoining
pieces, or their ultimate position and use. For instance, it is applicable in boat
building for the bull and deck seatns; for the floors of verandahs, and other open
air floored spaces; for walls and partitions of wooden buildings; and for certain
domestic work, as parquet-flooring, horticultural buildings, pavilions, temporary
ball rooms or similar structures, which being constructed partly of wood, partly of
timber, and partly of glass, with the various sections of the different materials
employed kept as small as is consistent with stability, demand the use of the
most elastic joint it is possible to adopt. The adhesive properties of a length of
my jointing material prepared by soaking, as hereinafter more particularly described,
are such that, by its use, a good and practical joint can be made between glass and
wood, or between iron and wood, as well as other materials.
Its application is not by any means limited to the joining of wood to wood.
The material I use to form the body, so to speak, of the joint, and to carry the
proper charge of vegetable gum, is cotton flax, silk or similar vegetable fibre, either
spun or woven, or both combined. For ordinary jointing, I use the material known
as duck and canvas, single or multiple,-in strips about as wide as the thickness
of the boards to be joined.
Having decided. upon the number of plies necessary to allow for the joint-it
being palpable that the greater the "opening" to which the joint may be subjected
by high temperatures, the more body" and capacity for following the edges of
the timbers the joint should possess the duck is cut off and folded.
"
The next step is to traverse it through, or soak it in, the gum: This can be
done in any convenient or suitable way, care being taken that every facility be
allowed for the duck or whatever material is used to absorb as much gum as it is
capable of retaining. I find a suitable way for making the folded duck absorb the
gum satisfactorily is to slowly draw it through a suitable trough, from which any
excess gum can be returned to the store tank.
The saturated duck is transferred to a warın room to effect the oxidation of the
gum, when it will be ready for immediate use, or to be despatched to the user.
The gum waste mentioned above I find to be the best for the purposes of my
invention. Copal varnish may be used. It is, however, more costly and inde-
pendently of the question of price, I am guided in my selection by the non-liability
of an otherwise suitable gum or varnish, to evaporation in a dry heat.
The relative proportious of fibrous material and gum which I have found yield
very good results are 4 oz. of gum and 2 oz. of fibre, spun and woven, or either,
in a length of two feet of joint or seam.
To make a joint of the strip of duck prepared as above described, the first board
or piece being laid, the strip is held in position against its edge, and the adjoining
board or piece forced against it, by exerting a proper degree of pressure in the
uccessary direction. When the several pieces have been approached as closely as

page_text: is necessary, they are to be, or may be, secured in any convenient or workmanlike
manner, to such cross timbers, joists or equivalent pieces as the size of the work
may require.
When a folded strip is used, the fold is always at the bottom or inside. The
protruding rough edges are shaved off, leaving the general surface smooth, and the
seams sightly.
One benefit of my invention, and indeed one of its aims, is the abolition of the
use of the well-known caulking tool, and, with it, the damage it does to the edge
of the boards, and the uneven edges it produces-Besides this, the use of a caulking
tool would be impracticable in making a joint where glass is one of the materials
to be joined.
It is not necessary for the production of a workmanlike joint, according to my
invention, that the edges of the boards should be prepared with as much truth and
exactitude as is usual in good cabinet work for instance, inasmuch as some degree
of roughness of surface, provided that it stops short of actual irregularity of outline,
may have the effect of giving the edges of the boards, iron bars, or whatever may
be the parts to be joined, a firmer adhesion to the strip of duck.
I do not confine myself to the making of the adjacent edges of the timbers, or
materials, to be joined, parallel, as they may sometimes, as in the case of deck
seams, be advantageously made with one edge, or both, concave, so as to produce a
cavity which is occupied by a length of duck folded and (preferably for large work)
with a core of cotton wick or yarn. This folded strip is not made wide enough to
occupy the full depth of the seam, a separate strip, two-ply as wide as the seam is
deep, being laid against one edge, and a bead, or projection, from the bottom of the
opposite edge filling up the vacant space, and serving as a closing bead to prevent
the possibility of the gum, liquefied by hot weather, dropping down.
Instead of using one, two, or three-ply strips, I may use cotton wick, or yarn,
steeped as before described, and laid between the edges to be jointed in the manner
already explained.
For repairing failing joints of any kind, or replacing broken joints, by my inven-
tion, this yarn type of joint is the most convenient application of my improved
system. It is not to be caulked in, (using the word "caulked" in the well-known
sense), inasmuch as has been already explained, the abolition of this practice is one
of the aims and results of my invention. I use a, preferably, metal roller, the
periphery of which is proportioned in point of width, to fill the space between the
two edges to be jointed, and roughened so as to give it "bite."
down along the joint and rolled in until the joint is made.
The
yarn
is laid
A comparison of the action of iny improved system of jointing with that of joints
made with oakum and, what is known as, marine, or elastic weather-proof, glue,
under various temperatures and conditions of weather, will throw further light
upon the essential features and properties of my invention.
The oakum and glue joint is contracted when the boards swell, the oakum is
crushed and the glue is caused to protrude above or outside the surface, whilst,
under corresponding circumstances, the material of my joint is simply squeezed,—
it is too elastic to be crushed, or to be made to protrude.
When the oakum and glue joint is expanded by the heat, the edges of the boards
are drawn away from the oakum, and the glue can only follow them, provided that
it can sink enough below or from the surface to compensate for the "stretch."
Under similar circumstances, a joint made according to my invention would neither
be left behind the receeding boards, nor sink between the latter. Its innate
distinctive elasticity allows it to follow the receeding edges, and to close upon
itself as the boards expand again.
The accompanying drawings illustrate various types of joint which can be made
according to my invention, and are not to be taken as illustrating all the applica-
tions of which it is capable, which have already been enlarged upon.
Fig. 1 is an end elevation of a joint made up by the insertion of spun and soaked
cores a, with a single strip of duck at at the side in the groove or joint spaco

page_text: between two boards B, B. A closing bead c is shewn as formed on the edge of
each board. The joint space is shewn as made wider towards the bottom than at
the top for the reception of a larger quantity of elastic joint material.
Fig. 2 is an end elevation shewing the jointing material partly folded and with
a loosely spun core; the two boards; and the closing bead on one board.
B, B, are the two boards, c is the closing bead; d is a two-ply strip of woven
material; e is a three-ply folded strip, with a central core, a¹, of loosely spun yarn
or fibre, the joint space is shewn of the same section as in Fig. 3; and the tops of
the jointing material is trimmed off smooth.
Fig. 3 is a sectional elevation of a finished joint; the closing bead is shewn as
part of one plank as in Fig. 1.
Fig. 4 is a side elevation of an insertion roller suitable for making a core joint
as illustrated in Fig. 1.
Figs. 5, 6, and 7, are, respectively, sectional elevation and plan and sectional
elevation on an enlarged scale, of a two-ply joint. The edges of the boards B, B,
are parallel. The projecting edges, a³, a², of the jointing material will be trimmed
off when the joint is completed, while the fold, a³, may either project as shewn, or
the joint may be closed with a closing bead, after the manner illustrated in
Figs. 1, 2 and 3.
Having now particularly described and ascertained the nature of my said inven-
tion, and in what manner the same is to be performed, I declare that I do not claim
as part of this invention the method of making a boat plank joint according to the
invention described in my specification N° 14212 of 1884 and claimed thereunder,
but what I claim is
1. Making an air- and water-tight boat- or ship-plank joint, or scam, by soaking
cotton, flax, silk or similar fibrous material, spun or woven, or both, in vegetable
gums of the hereinbefore described kind, and fixing or inserting the said material
between the edges to be joined together substantially as described.
2. Making an air and water-tight joint between two adjacent edges of materials
used in the construction of floors, partitions, walls, roofs, by inserting between thein
woven or spun (or both combined) cotton, flax, silk or similar fibrous material,)
previous soaked in varnish or varnish waste, or the dregs of foreign vegetable gums,
substantially as described.
3. In making an air and water-tight joint between two adjoining edges of
constructional work, the use of one or more loosely spun cores of yarn, previously
soaked in varnish or varnish waste, substantially as hereinbefore described.
4. The combination with a joint made of fibrous material and varnish, or varnish
waste, of a projecting closing bead or beads for the purpose of preventing the gum,
or the like, from dropping down or exuding.
Dated this 21st dose of Do100-