NOTE:
This article appeared recently in Traditional
Bowhunter Magazine, entitled "Gluing Rawhide to Self Bows."
It appears here in two parts with a new and interesting wrinkle at its
conclusion for those who would like an inexpensive method for gluing wooden
backings to bows.
Gluing Rawhide and Veneer to Self Bows
Part I
Hide glue absorbs moisture readily. It chills off quickly, turning to jelly
soon after its application to glue surfaces. It is also sensitive to heat.
You'd think these "faults" should eliminate hide glue from the
list of bonds for rawhide bow backs. Wouldn't it make more sense to choose
a modern aliphatic resin glue such as Titebond II, which resists both heat
and water and is slower to tack, providing a longer working time?
I've used at least five different glues
for this bond. They all worked. Each had advantages and disadvantages.
But for ease of application and certainty of bond, traditional animal hide
glue is the superior choice for rescuing bowwood with rawhide. The same
three faults catalogued above, together with hide glue's natural affinity
for rawhide, actually become strengths and are used to advantage in the
application method whose explanation follows.
Avoiding the Future
Bows are backed with rawhide to prevent breakage
rather than to increase cast. Candidates for rawhide are those bows likely
to lift a wood sliver as a farewell gesture. They would include: 1) somewhat
close-grained hardwoods, especially those with pin knots; 2) plain-sawn
or rift-sawn (rather than quarter-sawn) sawmill boards; 3) staves or billets
whose integral growth ring along the back has been cut through; 4) yew
self bows.
The Tools
You need only two tools for bonding rawhide to
wood: an electric iron and a cabinetmaker's veneer hammer. You can rescue
an iron from disuse from almost any laundry room closet; you can make a
hammer with found or begged materials. The iron functions to re-liquefy
chilled glue and the veneer hammer follows behind as a squeegee.
To make a veneer hammer head, plough an
1/8" saw kerf into the end grain of a 3/4 to 7/8" thick piece
of hardwood stock across its width and to a depth of 1/2". No need
to center the plough. Rip the stock to a net width of 2 1/2" and trim
to a length of 5". Grind, saw or plane a 30 degree facet onto the
fatter lip, or onto both lips if you've nearly centered the plough. Epoxy
a brass blade 1/8 x 1 x 2 1/2 inches long into the plough. If brass is
not available, copper will do. If not copper, simple steel bar stock will
work. In any event, file and polish the exposed edges so that they will
glide smoothly over the rawhide without tearing or scratching it.
Anything from a thick dowel to a dry tree limb whittled to fit the socket
hole you drill through the center of the head will work as a handle. Saw
a kerf about 3/4" deep into the fitted tenon end. Work some leftover
epoxy into it and swab some more around the mortise socket. Twist the tenon
into the mortise so that the kerf ends up perpendicular to the grain direction
of the head, and then pound a wedge of soft stiff wood like poplar or walnut
into the kerf. (Flare the mortise with a rattail file where the wedge expands
the tenon if you want a fit that will hold up even if the glue fails.)
Smooth things up and chamfer the edges so that everywhere the hammer is
comfortable to hold. Sometimes you'll grab and use it one-handed.
About Rawhide
Bows backed with rawhide from deer you've hunted
add medicine to a process already imbued with reverence and pride. Making
rawhide from your own deer kills is uncomplicated. If you aren't familiar
with the process, the local library has all the information you need.
The hide from a mature whitetail doe is
the right thickness for most needs. Skin from bucks is twice as thick and
as such makes a safer mate for close-grained hardwoods with pin knots which
may as likely snap in half as peel up a sliver. For most applications,
however, buck hide needs to be scraped thinner from the flesh side after
it has dried. A sharp cabinet scraper proves a valuable tool for this job.
(See TBM Self Bow column, ?/? 96)
Setup and Preparation
In addition to the water used for melting your
glue, you'll need a very warm pan or bowl of clean water as well as a means
for maintaining its temperature. It's used for wetting and rinsing a glue
cleanup rag, for dampening the rawhide and as a station for heating the
metal blade on the veneer hammer. When the hammer is not in use, lay it
with its blade in the water, absorbing heat.
Cut two pieces of rawhide, one for each
limb, about one inch longer than the limb from mid-handle to tip. Cut the
rawhide off limb tracings so that everywhere it laps over the sides no
more than 1/8". More than this and the drying process tends to curl
the overhang up and away from the edges.
Clean off any rough stuff still clinging to the flesh side and mark the
flesh side so you will be able to identify it as the glue side. Once the
rawhide has been wetted and softened, this determination is difficult to
make and can result in an upside- down glue job.
Set the iron for a temperature that is just warm but not quite uncomfortable
with the iron held about an inch from your cheek. Too hot and you dry out
the rawhide, curling it away from the wood like a board laid down on wet
ground in the sunlight. Practice on a scrap to find the setting that evenly
warms the glue.
If you are lucky enough to have some of Granny's homemade lye soap, use
it to wash the glue surfaces of both limbs. Fel's Naptha substitutes for
caustic soap. Wipe to rinse with the dampened cleanup rag. This cleansing
will maximize adhesion. It matters more if you are using oily woods such
as Osage or most any tropical hardwood. The limbs can be damp when you
spread them with glue.
Continued.
