sapwood, good or bad?

[stuckinthemud]

Hi All,

I realise that yew sapwood is good in tension and that is why yew is such a brilliant bow-wood, but I was always taught that sapwood, in general, is nasty stuff as far as fine wood-work is concerned, being prone to disease and bug-infestation, too soft, compared to heart-wood and should be cut away whenever possible.  Now, in the world of bow-making, we seem to keep the sap-wood on, working just below the cambium? Is this the case, or not?  Some species have quite broad bands of sap-wood, so do I work in the heart-wood, or across both?

[Pat B]

From your thinking all whitewood is bad. I've made bows from osage sapwood and mulberry sapwood and both made good bows. It is true that heartwood is generally stronger than the sapwood but IMO it is not trash in either of these woods. If a bow is designed properly and the woods physical characteristics are considered good bows can be made from sapwood of many woods. With red oak and white wood, elm and other "whitewoods" the sapwood is preferred. Most whitewood bows are made from the wood under the bark, ie. the sapwood.
 Learn the physical characteristics of the wood you plan to use and use the design that suits those characteristics best and you can be a successful wood bow builder.

[George Tsoukalas]

If I have enough heartwood I remove the sapwood from osage and black locust. In these woods the sapwood turns to heartwood.

If I don't have enough heartwood  I leave some sapwood but get as close to the heartwood as possible figuring the sapwood is stronger then.

For whitewoods just take off the bark and make a bow. The sapwood is string.

Jawge

[PatM]

That's not true at all as far as fine woodworking is concerned. Many  high grade woods for woodworking are just sapwood.  Sapwood is only a problem for outdoor wood applications.

[stuckinthemud]

mmm, yes, umm, I guess that sweeping statements always stir up controversy. apologies.  However, as I see things, heartwood is the dead wood in the middle of the tree, and tends to be harder, more dense, and more resistant to pests; sapwood is the living timber, and is softer, less dense, and more prone to attack.  Wood-carvers tend to avoid spongy timber where possible and so avoid sap-wood (this is a general, nay sweeping statement!).  Certain species' sap-wood is a very narrow band and so of no consequence, whereas other species' sap-wood bands are very broad and the entire thickness of a limb would be contained within the sap-wood, hence my question. Perhaps if I modified the question to, 'if the stave were deep enough is it better to remove the sapwood or does it not really affect the performance of the finished bow?'

[PatM]

 Still depends entirely on the tree.  Many trees form heartwood that is inferior to sapwood. The heartwood is resistant to pests argument is moot when the sapwood is on the outside.
 Not sure what type of woodcarving you are talking about but basswood is considered a great carving wood and it's the sapwood that is used.
   The trees which have actual stronger heartwood are well documented. For everything else you are better off using sapwood.

[Josh B]

It should also be pointed out that the sapwood is just as dead as the heartwood.  The cambium is the only actual living part.  The heartwood is harder and more rot and insect resistant because its had more time to soak up the "resins"(not the proper term, but you get the idea) that change the woods properties.  The biggest problem I have with sapwood on Osage, mulberry and the like are self induced for the most part.  If I were to be more diligent in storage and treatment of the staves like I am with say hackberry or elm.  Then the sapwood works fine as the back.  Also heartwood is not always better than sapwood.  ERC for example. The heartwood is extremely brittle in tension, but leave a nice sapwood back and its fine...well better any way.  Josh

[Jim Davis]

And for centuries, the sapwood of hickory has been preferred for any application where strength and flexibility are desirable, such as handles for hammers, axes, rakes, pitch forks and bow.