Special Use Requirements

(1) For fishtail splices in staves and for footing joints in arrows, high strength and water resistance are important. A good fit and a larger bearing surface affect dry strength more than the type of glue. In staves the bearing surface may be enlarged by keeping plenty of thickness under the handle. In shafts a sufficient bearing surface is assured if the length of the splice is at least 15 times the diameter.

(2) The choice of glue for attaching feathers to shafts depends on the degree of water resistance desired and on the rate of gelling of the glue for the particular mechanical method used for feather attachment. Animal glues have been used, but nitrocellulose-base cements (pyroxylin) now seem to be preferred and appear to have acceptable moisture resistance.

Glues of the woodworking types, known to be more moisture resistant, are not generally convenient to use for attaching feathers because of their slow hardening under normal conditions.

(3) Glues for attaching bow backings and facings must produce bonds that have high strength and high moisture and water resistance and that are able to bend with the bow without failure. Glue films applied to the wood for laying sinew, silk, or high-tenacity rayon fibers as backings and facings must bend without cracking. Animal and certain resin glues have been used for these purposes.

Gluing Properties of Archery Woods

Since a good glue joint is usually considered to be one that is stronger than the wood being bonded, the stronger high-density species require stronger bonds than the low-density woods. Therefore, more careful control of the gluing conditions is required to produce satisfactory joints in hickory than in spruce or pine. Oily woods, such as yew, osage orange, or lemonwood, that are commonly favored for bow staves may be more difficult to glue than woods of the same density but without oils, resins, or extractives. Oily woods may glue better when freshly machined than later. Sponging oily wood surfaces with a 10 percent solution of caustic soda, wiping off the excess, and drying before gluing often improves gluability with animal and casein glues. Since residual alkali is likely to interfere with the catalyst systems of many urea- and resorcinol-resin glues, this alkali surface treatment should not be used with these resin glues. Gluability with these resin glues may, however, be improved by the use of somewhat elevated curing temperatures — 100° F. or so — during the pressure period. Care must be taken to avoid excessive drying of the wood during such curing of the glue.