Red Oak-backed Cypress 62"ntn recurve

[Nezwin]

I've been tinkering with this one for a few weeks, not been able to get in the workshop much of late. 64" total, 62" ntn, 1.5" wide at the fades, parallel with for 14", tapering to 1/2" at the nocks. 12" static recurve cut in with the kerfing method and a 1/8" Red Oak-backing pulling 35"@26".

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Tiller isn't perfect but after some caliper work it tidied up quickly. Each bow is getting better & better, at least.

Developing on from the previous Hickory-backed Cypress bow I wanted to see how the timber works in other styles. I also wanted to try out Red Oak as a backing on something as elastic as the Cypress - there's a lot of folk without easy access to straight-grained Hickory or who's skills warrant a more humble material. I had a bit of trouble initially where the kerf ended but that was cleaned up pretty quick with some added epoxy. Then, similar to Hunterguy Colin's recent recurve only far worse, I had some serious limb alignment issues.

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To the eye the form seems okay but I'm pretty sure that's the source of the problem.

After unstringing I noticed a few cracks...

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This is on the recurved section of the limb and I'm pretty sure it's a result of the twist in the limbs, so I'm resigning this bow to experience. Bit of testing there for those interested, though.

[Nezwin]

Following on from this bow, I used timber from the same board to make a laminate bow over the weekend, which subsequently exploded. It showed no sign of compression fractures but, interestingly, did show signs of longitudinal cracking. I spoke with the owner of the local Cypress mill and he was of the opinion that Cypress was "too brittle" for bows, which this particular board would appear to pay testament to.

Comparing this recent board against another I've picked up shows drastically different shading & grain.

Cypress vs. Cypress -

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The boards from which I'd successfully made a Hickory backed bow (http://www.ozbow.net/phpBB3/viewtopic.php?f=34&t=15774) were more like the darker coloured timber.

Original, successful boards -

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I did a little more digging around and am starting to believe that the darker timber is in fact Black Cypress (Callitris endlicheri) while the lighter coloured timber is White Cypress (Callitris glaucophylla), the Black Cypress being the less brittle & more elastic of the two. These being sold as the same product would be similar to the manner in which Mountain Ash/Tasmanian Oak is actually a series of different species of varying properties.

I'm happy to stand corrected and would encourage other people to give it a shot. I'll be passing a few blanks out to members of the forum when we next meet in person, so it'll be good to see how anyone else's efforts pan out. If you do go to buy some of this timber, be sure to select the darker-grained species, as knot-free as possible.

[hunterguy1991]

Good research and info on the timber Neil.

Just been looking at this bow for a bit and I've got a suggestion. Basically the same thing that I did from first to second kerfed recurve, I would make the recurved section a bit shorter so that you have a little more working limb to work with. This helps to minimise set and doesn't push the timber quite as much in close to the fades where it is thicker.

Shorter section wrapped around a slightly tighter curve should have the same effect as a longer one around a more open curve.

Colin

[Nezwin]

Good research and info on the timber Neil.

Just been looking at this bow for a bit and I've got a suggestion. Basically the same thing that I did from first to second kerfed recurve, I would make the recurved section a bit shorter so that you have a little more working limb to work with. This helps to minimise set and doesn't push the timber quite as much in close to the fades where it is thicker.

Shorter section wrapped around a slightly tighter curve should have the same effect as a longer one around a more open curve.

Colin

Cheers, Colin.

I'm going to give this timber combination another shot with a design similar to your Greybeard-inspired bow, following your advice. This one was a bit of a test to see if it would fail in compression on a short, highly-worked limb. Which it didn't! But other problems arose and it did show the start of failure on the thick recurved section. I'll post the next experiment up when it's done and share the progress.

Incidentally, I visited the mill in Narrandera today and they were good enough to give me a tour. It's an impressive site. I asked about the difference between the lighter and darker timbers and it seems they are definitely the same species, the darker timber only being denser. This is important as I believe it's this denser, darker timber that holds promise. When I lifted two boards of equal size but different colour, there was a big difference.

They showed me the roundbacks but the sapwood was a good inch thick or more, too thick for bow making without modification. When I bring my own large tree down I'll maybe consider decrowning or thinning, worth a try. The owner seemed to think that the sapwood was so tight that even a thickness of sapwood on a dressed board, regardless of growth ring violation, would still hold together - although he did say he isn't an expert at all. But at $4-ish a stave, I know there's a board locally that would fit that bill that would only take an hour or so to work into a bend-through-the-handle, crowned longbow. I remember seeing a layout that Dennis posted once for a whip-ended ELB...

[hunterguy1991]

I can PM you a good starting point for an ELB if you'd like to give it a crack on the timber?

[perry]

Like your approach to Bowmaking Neil, one great big opportunity to Learn. In my experience the Sap wood on every Aussie timber I've ever tried handled Compression and Tension just fine. Aesthetics was the only reason to thin Sapwood in my view. As the Timber fella said, even with violated growth rings the Sap Wood held together.

Spotted Gum is another one where the best Timber for Bows is the Darker Pieces, the Honey Coloured stuff is not quite a Dense. I also found that the best Spotted Gum grew on the Northern New England on a Plantation the Yard I used to buy it through had near the Bruxner Hwy. Lancewood due West of Sydney was better than the same species growing West of Brisbane, Pink Ash is best from Sandy Soil and not from Rocky Ground generally. I'm would not be surprised if the best Cypress could well be regional.

regards Jacko

[yeoman]

Good legwork on the black vs white cypress, and good work persevering though the pain.

I've made a mental note to only seek out the darkest cypress samples.

I've used the caramel-coloured spotted gum a few times and while it may not be as stiff/elastic (no idea, never tested or noticed), it does make for a spectacular aesthetic.

An interesting test would be to compare the density/elasticity/stiffness from one white cypress tree (or flitch), sampling sapwood and heartwood in isolation.

[Nezwin]

Good legwork on the black vs white cypress, and good work persevering though the pain.

An interesting test would be to compare the density/elasticity/stiffness from one white cypress tree (or flitch), sampling sapwood and heartwood in isolation.

Time in the shed is rarely painful, even if I don't get a working result. It's my "Happy Place"

Would be interesting to test the heartwood & sapwood separately. I'll have samples in the next 6 months or so, if I get this tree down.

Like your approach to Bowmaking Neil, one great big opportunity to Learn. In my experience the Sap wood on every Aussie timber I've ever tried handled Compression and Tension just fine. Aesthetics was the only reason to thin Sapwood in my view. As the Timber fella said, even with violated growth rings the Sap Wood held together.

Cheers, Jacko. The day the wood stops teaching me is the day I give it all away! Tim Baker and his mates have done so much work on North American bow woods, it would be good to have a record of everything tried with Aussie woods. From your posts, it seems you blokes have tried pretty much every timber out there over the years, it would be great to have a reference of all those bent sticks material/length/width/shape...I'll be getting a sapwood backed board probably later today, it won't take an hour to cut to shape, sand and put a couple of nocks in. I'll make it plenty long and she'll either explode or not, it'll be interesting either way.

Spotted Gum is another one where the best Timber for Bows is the Darker Pieces, the Honey Coloured stuff is not quite a Dense. I also found that the best Spotted Gum grew on the Northern New England on a Plantation the Yard I used to buy it through had near the Bruxner Hwy. Lancewood due West of Sydney was better than the same species growing West of Brisbane, Pink Ash is best from Sandy Soil and not from Rocky Ground generally. I'm would not be surprised if the best Cypress could well be regional.

I'm pretty surprised at the breadth of the density variation, to be honest, and how much that can impact the mechanics of the material. All fun & games though, we'll see how things pan out with the next attempt, and the next attempt, and the one after that