Virtually all all-wood (self) bows will slowly develop a constant curve during normal
usage. This is termed "following the string" (Yew is one of the few woods which should
return fully to its correct shape and even it will usually develop string follow.). This
curving will effectively reduce the draw weight of the bow slightly. This curve can be
removed by carefully and slowly heating the complete bow until the wood becomes
slightly softer, the wood can then be curved to the desired shape and slowly cooled
again. The whole bow should be warmed at the same time, not in stages, so this can be
done in a section of pipe with the ends closed, and the heat applied to the pipe, rather
than directly to the bow.
As long as the wood is not overheated or burned at all, it should return to straightness
and recover most (if not all) of the lost poundage. This will, of course, not be permanent,
but can greatly enhance the effective life of the bow Because of this and other reasons, it
is always a good idea to unstring any all-wood bow any time it is not required for use
for more than an hour or so. Many modern composites (recurves and compounds) do not
have this problem as much and are often left strung for extended periods, but for any self
bow it is important to unstring them after use.
Staves made from twisted timber such as Osage Orange, can be straightened with careful application of heat from a gas stove provided that the timber is protected by application of fat or candle wax or similar to prevent burning. This method is also used to straighten bows which have developed curves or twists during use. Carefully and slowly heating the complete bow allows the wood to become slightly softer, the wood can then be curved to the desired shape and slowly cooled again. The whole bow should be warmed at the same time, not in stages, so this can be done in a section of pipe with the ends closed, and the heat applied to the pipe, rather than directly to the bow. As long as the wood is not overheated or burned at all, it should return to straightness and recover most (if not all) of the lost poundage. This will, of course, not be permanent, but can greatly enhance the effective life of the bow.
Offered by Brian.