Ozbow

Hi all,

First time posting here. I'm a Western Australian based in the USA and have been making selfbows for a few years. We have it lucky here, with the plethora of good native bow-woods, but I often wonder about the potential of native Australian woods for selfbows. A while back I compiled a list of woods, to compare Australian species with those from other places (see the attached spreadsheet). From this simple list it really looks like there are some good possibilities. To me it also suggests there must be other species out there that aren't on this list.

Cheers

Nic

Of course, how the wood should be rated is a good question. Sorting by density, MOE, MOR, relative strain or crushing strength gives different rankings. I've found that sorting the North American trees by MOR puts things like osage, ipe and hickory at the top, so I take that as meaning it is a reasonably accurate. Things like karri, wandoo and mulga all rank highly then.

Hi Nicholas, Have you tried a search on Australian woods on this site? If not ,I would recommend you give it a go. This kind of question comes up fairly often. The short story is many Aussie woods will make good bows if designed correctly. However MOE and MOR etc, don't necessarily translate well into what makes a good bow wood, in terms
ability to resist compression without with out fracturing. Most of those terms are applicable for structural beams poles etc.
Hamish.

Hi Hamish,

Thanks for your response. I have poked around here and Paleoplanet over the years to see what Australian woods folks are using. I've noticed that people talk about Eucalyptus sideroxylon, Eucalyptus maculata and Acacia harpophylla. Based on their properties many Eucalyptus and Acacia should in theory make good bows, but the inexact correlation between properties like crushing resistance and "bow-suitability" is interesting. Given their mechanical properties I'd assume many Australia species wouldn't be brittle and would resist frets, but as you point out, it's not that simple.

I am particularly curious about many of our Acacias. Based on their physical properties they could hypothetically be better than Euc's, and the experience of Australian bowyers seems to bear this out http://paleoplanet69529.yuku.com/topic/ ... 2ZetcdM51E

Nic

Hi Nic, The denser acacias seem make pretty good bows, The problem for most people is that the trees usually grow in remote places, and are usually not found in bow quality sizes at specialty wood stores.
I find its better at first to use a proven bow wood to learn proficiency, then experiment with local woods.
A really good wood like osage is hard to go wrong with if you are patient. Other woods can require that everything must be done perfectly to get the same results. I have seen bows (and made some myself)from eucalypts that have excellent tiller and low set yet still have chrysals. Another stave from the same tree even with the same or not even as good craftsmanship can show no chrysals.
Hamish

I think the attached list was posted on Ozbow some time ago.

Daryl.

I've made osage, ipe and hickory bows that have failed due to frets so no wood is perfect!

You mention how hard it is to get bow-quality staves from Australia timbers. I believe it. Don't underestimate how hard to is to get bow-quality wood from North American species though! Things like osage and yew have restricted distributions and also tend to grow in inaccessible or off-limit places. Once you find trees the number of good staves versus knotty, twisted and bug-eaten staves is fairly low!

Hi Nic, I have never seen a piece of hickory, osage, or ipe fret, unless it was due to careless and or hurried tillering, like a severe hinge pulled before correction. Some of the proven timbers when backed with hickory or bamboo can fret, but these are at knots or wavy grain. These could have been avoided if a compensatory bump was left at these spots during tillering. The kind of problems with most of the Australian eucalypts that I am talking about is not due to bad tillering or being too short. The first bow made from a certain batch of wood eg spotted gum, or ironbark, same design, might show no problems, the next bow made like the previous one might just fret despite being tillered just as carefully as the first. These problems could probably be avoided if the bow was made even longer or wider than its density would suggest, greatly overbuilt when compared with other similarly dense proven bow woods.

Some woods like Victorian ash barely get past the braced stage before getting chrysalis despite no even being pulled very far.
The Australian desert acacias and some Australian rainforest timbers seem to perform with more consistency, like traditional bow woods.

The good thing about US woods is that even if you don't live near where they grow, there are established market places that will sell bow quality staves and billets culled and prepared for sale by bowyers at reasonable prices. In Australia these are only just developing. Much of the time they are cut by some enterprising individual that has no experience with selecting and seasoning bow wood. The result is substandard yet they still expect top dollar, for what is no better than checked firewood.

Admittedly most failures in US woods were due to inexperience in years gone by. However some have been in well-designed bows (well-designed on paper at least) and still failed. I recall a hickory selfbow that a friend made a two years ago. It was long, wide and tillered well, and the damn thing still developed frets all along both limbs! The members of our bowyers group all stood around scratching our heads. I think the lesson to take away is that wood is predictable to an extent, but is still a natural product that varies greatly due to genetics and environmental conditions.