Hickory wattle sapwood/heartwood question

[Brumbies Country]

I'm about to make a self bow out of hickory wattle (Acacia falciformis). Just wondered if others have worked with this timber before. The timber has been cut about a year. I'm just in the process of stripping the fairly deply fisured bark off (bark is a bit like elm bark and not easy to remove at this stage) Below that is a thin layer of white sapwood over a dense reddish brown heartwood. The sapwood looks on the soft side.

My question is with this timber, should I keep a layer of sapwood on the back, or as often is done with osage, use only heartwood. I made a similar bow from black locust beginning of the year, retained the sapwood and then wished I hadn't. It turned out to be a lovely looking character bow, a fair bit of ping at 45lbs @27" but now with small fissures in the sapwood. Next one of those I thought I'd cut straight (no pun intented) to the heartwood.

Any advice re this timber most welcome.

Simon

[otis.drum]

i haven't used the wood, but have made light selfies with sapwood left in place. glenn newell has had good results leaving sapwood on.

what do you think caused the fissures in the last one? do you think it wasn't fully dried?

i have found a couple of wattle staves to be touchy and splint and crack, and wonder if leaving the sapwood on ma help this.

[longbow steve]

Hi Simon, if it is anything like Blackwood then the sapwood would be useless. I think the sapwood would only be useful on the denser acacia's but you never know. Steve

[Brumbies Country]

i haven't used the wood, but have made light selfies with sapwood left in place. glenn newell has had good results leaving sapwood on.

what do you think caused the fissures in the last one? do you think it wasn't fully dried?

i have found a couple of wattle staves to be touchy and splint and crack, and wonder if leaving the sapwood on ma help this.

Thanks Otis

With the Black Locust I did do the quick drying routine. Debarked it, sealed the ends, wrapped it in cling wrap while I thought about the best approach, then removed the cling wrap for periods and placed it in a grain store, The latter is corrugated iron and elevated and pretty high ambient temperatures. I'd had previous experience of allowing hawthorn to dry too quickly after sealing and debarking and I got cracks in the sapwood. With the Black Locust I exposed it for about 8 hours at a time and weighed it, then cling wrapped it again. Finally started working it once weight loss was close to zero. Paul Comstock describes similar methods in the Bent Stick. It's possible it may have not dried sufficiently. the tillering initially looked good, but after the fisures (chrysals, I guess) the tiller is not so good. I'm half tempted to try to correct that, but the other half of me likes the look of it to much to risk it.

Like alot of us I'm an enthusiastic amateur. It's alot of the fun having an educated guess and trying to get it right; to date I've got four self bows that shoot to expectation. I've two that look good and shoot OK but that could well break if I persisted ( including the Black Locust bow). Also one that broke after around 400 shots, and three that broke pretty well straight away. I've also had two that I scrapped during tillering. You live for the expectation that you get one that is above average. I compare them all with the two ELBs I've purchased.

Simon

Simon

[Brumbies Country]

Hi Simon, if it is anything like Blackwood then the sapwood would be useless. I think the sapwood would only be useful on the denser acacia's but you never know. Steve

Thanks Steve

I haven't looked at Blackwood closely. This is a heavy stave at around 71/2 feet long and 4 inches in diameter, so I suspect that the heartwood has a high SG. It certainly looks dense. The brown heartwood tends to red and would come up really well with the right finish. This is one of the acacias, along with A doratoxylen(Currawong, Lancewood) that is predicted to make a good bow wood, so I don't want to stuff it up. I must say that the sapwood at first glance doesn't look great. I've got a day off tomorrow and I'm going to play around with it. Not a bad way to spend an otherwise cheerless winter's day in these southern regions .

Simon

[roscoe]

Simon, i have a couple of staves out of an acacia my self. What am going to do for the first one is remove the sap and decrown the back. I dont know how it will go, but i will have that down by the weekend, i will let you know how i go. The staves a still green at the moment and it will be a few weeks before i make the bow. I have just finished a bow from this timber and its all heart wood... Roscoe

[Brumbies Country]

That must be the one that you just posted Rosco and it looks good. I did a slat bend test this morning made up of a section of the acacia I'm talking about here and it looks to me that I need to go the way you have gone. ie remove the sapwood and decrown

[roscoe]

Simon, It was a board from that acacia species, but it was a board that was like a decrowned stave if you know what i mean. I am in the process of decrowning a stave right now, i will let you know how that goes... Roscoe

[Brumbies Country]

Simon, It was a board from that acacia species, but it was a board that was like a decrowned stave if you know what i mean. I am in the process of decrowning a stave right now, i will let you know how that goes... Roscoe

Me too Roscoe . Just wondered how you are removing your sapwood. I'm using a power plane and it's fairly dusty. Just came in for a mask. In taking off the sapwood it's absolute confirmation that it's the way to go. Small erosions in places and would have been bad news to retain it. I'm taking it down just until I see a trace of the red-brown heartwood underneath The heartwood looks particularly dense with this species. I'll be looking for a particular growth ring.

Simon

[roscoe]

Simon, my sap wood is wet and comes off quiet easy, with a machette and draw knife. Simon, I searched the net about advice on decrowning staves, there was a lot of talk out there but no action. One thing they all seem to be doing is backing the stave with sinew etc. after decrowning. The other method is removing the sap wood and chasing a single growth ring in the heart wood. This would be very hard to do for our timbers because you cant see the growth rings like osage etc. So what iam doing is flatening the back out like a board bow. This has its disadvantages in that you must insure the ring lines all run parrallel with the back of the bow. Like i said simon this is new ground for me and i am not experinced in selfbow making, but if my board bow worked and it is a decrowned stave so to speak then i cant see to much of a problem. Its more up to the type of timber we use and i think personaly that our aussie timbers can handle a bit of grain violation. I to would like some input about this from some of our more experience self bowyers from this site. One thing you can count on simon is i will share any of my learning experiences good or bad for us all...Roscoe

[Brumbies Country]

Hi Roscoe

There is info out there that you need sinew backing but there's a bit of stuff in the Traditional Bowyers Bibles that supports unbacked bows long as they are wide and flat and reasonably long (66" or more). The American Indians certailny used sinew to back shorter bows, but there's plenty of unbacked bows of a variety of timbers mentioned in the TBBs.There is a fair bit of truth in the following one growth ring directive. What we don't have is a lot of information about native Australian timbers. There use to be a guy, Glenn Newall, on this website who knew a lot about native timbers. I guess we are feeling our way a bit with these acacias and it'd be great to swap notes as we go along.

Simon