Advice wanted on Osage Bow with Sapwood

[bentstick54]

I would like some advice from some of you experienced selfbowyers that have made some Osage bows and left the sapwood on them. I cut some 10” diameter Osage a week ago, and split it into quarters, and stripped the bark off. Sap was starting to run, so it stripped off cleanly leaving the sapwood unviolated. I sealed the sapwood and ends with shellac. All the staves have very thin growth rings. I count 24 to 30 per inch. Most seem to be about a 50/50 size mix between early and late wood rings. Thickness of the sapwood ranges from 1/8” to 1/4” thick depending on the stave. Most of them I can get clean staves with no pin knots showing through the sapwood. All are wide enough to give very close to flat backs.

My normal bows are around 50# @28” and 66” ntn., 4” stiff handle, 3” fades, 1-5/8 at widest part of fade straight tapering to 3/8” tips.
How much sapwood can I leave on if I don’t want to back the bow? What might I expect from a bow that is 1/2 sapwood and 1/2 heartwood?

[HH~]

Wiw 3” fades.

Ive made small dia Hedge bows that were almost all Sap Wood to 50@28”

Most my smal dia has good rings as it grows fast from 2” dia to 5” or i use a nice limb small dia.

Anyway small dia sapwood bows are Tough and make really snappy bows. The sapwood is much lighter in weight than yella wood.

HH~

[bentstick54]

Shawn, have you had any experience with staves split out off larger diameter trees?

[HH~]

Only made them from maybe 6" dia and smaller. Big stuff I dont leave any sapwood on it.

HH~

[bentstick54]

Thanks Shawn. These all have paper thin rings so was thinking it would be easier and safer to leave sapwood on. I know it’s been done before but I don’t know if I should thin the sapwood down or leave it as is since it has not been violated. I haven’t heard how the thickness ratio of sapwood to heartwood might effect the efficiency of the finished bow. Hopefully someone with some more experience will offer some more insight.

[Pat B]

If you must leave the sapwood on take is down to a small percentage of the overall limb thickness and back it with rawhide. With thicker sapwood rings you can leave a sapwood ring on the back with good results.  I've made mulberry bows that were all sapwood, half/half, a sapwood ring on the back and all heartwood. The more sapwood the thicker the finished limb will be. I assume osage will be similar.

[bentstick54]

Thanks Pat

[Onehair]

In Dean Torges book on self bows he states he has had excellent results leaving sap wood and that it benefits from steaming to eliminate the bacteria that will cause the wood to fail.