Primitive Archer

Main Discussion Area => Bows => Topic started by: Rākau on May 20, 2020, 03:44:37 am

Title: bamboo
Post by: Rākau on May 20, 2020, 03:44:37 am
Hello all.

Does anyone have any advice re cutting and drying your own bamboo for backings?
I recently have gained access to a bamboo farm and they have Moso bamboo at least 6" in diameter so perfect for maki.g backing slats. However, I have heard that big boo can be a bit tricky to dry.

Should I leave it in the round? or split it into strips and rough down to size? or is their another option availible to me?

Title: Re: bamboo
Post by: Ben.A.M on May 20, 2020, 04:15:50 am
Hi Zach, Iím sure youíll get heaps of advice from others but personally Iíve always split the bamboo ASAP to avoid mould as thereís a lot of moisture trapped in the cells between nodes, itís extremely easy to split and drys faster, Iíve used chisels, draw knife and at one point was using an old saw and just hammering it down the bamboo (probably donít do that) but youíll figure something out, itíll always split straight and you can split it to the dimensions you want then you can find somewhere airy to dry it, Iíve known some to just put it out in the sun to speed drying but Iím not sure whether that would have any negative effects, just be aware, itís sharp stuff! Wear gloves just in case, good luck!
Title: Re: bamboo
Post by: HedgeHunter on May 20, 2020, 06:39:57 am
Use harvest it green but found it was more work to deal with. So, I started harvest seasoned standing dead 6"-10" in dia . Can be a beast to rip out of the thicket as it get's very tall and dies almost vertical.

The green I left under cover vertical and water left pretty quick. Cut or split it, they have star blades they use for splitting at one operation. Then season some more, I fired it in a good small hot pile of coals at my Jungle Camp. Dragged belly side through it slowly (it has to be totally season before you do this). Then, cut it to thickness and sanded for use. Just like aging/seasoning bow wood really.

Good stuff. Made plenty Waiwi and bamboo backed pig bows in between teaching Rangers how to operate and fight in jungle and surfing.

Title: Re: bamboo
Post by: Eric Krewson on May 20, 2020, 07:03:15 am
DON'T split it green! It will often cup as it dries and be useless.

Cut it longer than you need it, I seal the ends (I put a bead of cheap superglue on the ends) just to keep checks from running in. Use a hoe to other straight handle to knock the nodes out inside the trunk so you can get airflow through it and let it dry evenly.

Let it dry until it turns from green to tan, pop a chalk line on it and saw it into slats with my bandsaw. I cut the inner node projections off with my bandsaw and flatten the belly either on my jointer or a belt sander with a 36 grit belt.

I have worked a ton of bamboo in my day for bows, magical stuff.

Title: Re: bamboo
Post by: gutpile on May 20, 2020, 09:04:38 am
first and foremost do not split your bgoo till it turns yellow.... NEVER... it will dry in a curl and be worthless... I let mine turn yellow and then I split.. needs to be big boo too... gut
Title: Re: bamboo
Post by: Ben.A.M on May 20, 2020, 05:36:55 pm
Wow! You guys must be getting some very different boo than what Iím getting or the climate is way different, Iíve gotten mould every time with every type of bamboo despite knocking through the nodes, only ever had success splitting it straight away, never had it check or cup, thought checking was impossible for bamboo, weíve got a heap of bamboo farms around here and the one I go to for specific types that donít grow on the side of the road knock out nodes and force air dry it in a shed with fans so it doesnít turn into a mould farm, crazy! Well, see what happens and go with what works :)
Title: Re: bamboo
Post by: PatM on May 20, 2020, 05:52:12 pm
There is some thought that cutting bamboo or trees in the right phase of the moon makes a big difference in moisture content.

 I have found this to be true.
Title: Re: bamboo
Post by: Ben.A.M on May 20, 2020, 06:56:57 pm
True Pat and I scout out my timber to cut in that time which for here in the Southern Hemisphere was a few wks ago but I wouldnít have thought bamboo would be as effected, so being mystified as to the differences in findings I just rang a mate who makes sculptures and structures for events and festivals from bamboo and he told me that bamboo grown close to water eg: creeks, dams, rivers etc especially in good quality soil grow a lot faster so the walls are thinner and have less density and youíll find a lot of it collapses under its own weight, also when split tends to curl with a large amount of shrinkage, which is where the tendency to cup comes from I assume, he also said heís never know of it checking although the structures they make only stand for at the most a month or so, what he did say is when they cut, they try and aim for close to the node as the process of cutting causes splits which may not be visible until it drys a little bit those splits never tend to go past the node, best bamboo is from poor soil conditions with minimal water access as it grows slower and denser, you could have 2 stands from the same stock grown in these 2 opposing conditions and you would barely be able to find a similarity in quality, also the walls of the bamboo Iím cutting here for the first 8ft from the base is rarely thinner than my index finger in which might make a difference also.
Title: Re: bamboo
Post by: Rākau on May 21, 2020, 02:21:04 am
Thanks for the feedback all. I have some bits that are a bit too beat up for a backing, so i will split them and see how they handle drying as slats, if that works out then I will split the good pieces too. In the mean time I have punched out the centers on the good bits and have them waiting patiently in the corner.


Ben.A.M, where are you based in the southern hemisphere? I am in NZ
Title: Re: bamboo
Post by: Ben.A.M on May 21, 2020, 06:34:35 am
Hey Zach! Iím on the east coast of Australia, where in NZ are you? Seems pretty much half the people I know are from there, man youíve got access to some beautiful timber over there, not sure about bow woods though but given your climate youíd be bound to track down some apple and plum in peoples yards, what are you going to use the bamboo to back?
Title: Re: bamboo
Post by: gutpile on May 21, 2020, 07:04:53 am
 I forgot to add bust nodes out of inside of boo for drying... then wait till turns yellow... but do not split till yellow or it will curl... gut
Title: Re: bamboo
Post by: Eric Krewson on May 21, 2020, 07:05:20 am
I used to cut my bamboo in NW Alabama, the patch is high on a ridge, the species is mandrake or giant timber bamboo.

I could store dry bamboo in my basement and it would mold, I found this out when I bought a 25 slat bundle from Franks in California. After loosing the 25 bundle of bamboo slats to mold I never put green bamboo in my basement.

I store my green bamboo trunks in my unheated shop while it dries. It stays in my shop until I use it for bows. The relative humidity here averages 12%, we have 100 degree summers and winters in the teens. The last few years have been very wet in the spring, we are about 12" of rain above normal so far this year.
Title: Re: bamboo
Post by: Hamish on May 21, 2020, 07:25:00 am
Ben, I buy my boo from Bamboo Australia. The last lot of stuff I got was direct from the farm. I wanted to try Madake, Japanese bamboo. They didn't have any cut, dried poles, so they cut a green one and split it up in front of me. The splits look fine to me, and haven't twisted. Its been about 3 years and they still look good.
I also bought a culm of Tonkin cane at the same time, it was dry, left in the round, and has lots of cracks, which might lead to loss of material, if I split it for bows. Probably less of an issue if I use it for  a split cane flyrod( been saying I'd make one, for years.

I'm not sure what the other guys are referring to as "curl" that makes it unsuitable for a backing. I haven't noticed any across the width, no propeller, and they still stay straight along their length. They can take a slight deflex bend, but that has no effect after you prepare it for backing.

Personally I don't think it matters when you split it, at least with the 2 types I just mentioned. Moso might be different though. All of the Moso I have got in the past was already dry. It usually has several uncontrolled splits, and mould in the interior. Still manages to make decent backings.

Title: Re: bamboo
Post by: Ben.A.M on May 21, 2020, 07:47:06 am
Hi Hamish! You must be pretty close to where Iím at! Iím in Murwillumbah and yeah, I think it must come down to varieties and climate, the fact that we average 60%-80% humidity on the mid north coast of Aus probably makes a huge difference also, found any good native timbers to use here?
Title: Re: bamboo
Post by: Eric Krewson on May 22, 2020, 07:11:03 am
Make a half circle with your thumb and first finger that, is what a cupped bamboo slat will look like as it dries. It will start out flat but the edges will curl up as it dries to form a "U".
Title: Re: bamboo
Post by: HedgeHunter on May 22, 2020, 06:08:35 pm
That would be some thin walled boo to do that or it was planed to this while green?

Doing a couple boo rigs right now. Have one 10yr old piece of good boo and a terd piece of yella boo green as a goard. Green one got the heat gun then up in shed rafters. In a month a plane it thinner then back in rafters. If you have green stuff, let it season! Green boo will check even after you glue it to your core wood!!! That really suks. Why I learned fast that boo aint nuthin but grass or cane. Better to let mother nature cure it standing dead in the Bamboo Break then cut that in dry season. Then again not everyone lives in the jungle where you can go harvest it.


Title: Re: bamboo
Post by: Hamish on May 22, 2020, 06:40:47 pm
Okay I get what you are saying about cup now. Thanks Eric.  There could be a some of that, but its not bad enough on mine to reject the slat.

The mature  madake boo seems  a bit narrower than  the average mature moso, so its going to have a little more crown once its flattened. Tonkin is even smaller in diameter so its only suitable for a relatively narrow bow, unless you edge join two narrow slats.
Maybe the Moso has more of a tendency to cup than madake.

Howard hill used to flatten his madake by steaming, then put in a press. So that might be a viable option( a lot of extra work though).

Ben. I'm down in Sydney. Bought the boo from BambooOZ on a holiday, easier top transport by car split than round. Plenty of good bow wood in QLD. Saffronheart(rainforest timber), on the east coast where you live. Also red/pink ash is a big favourite with local bowyers in your region. Seems pretty common around Gympie, as a scrub tree growing in the understory of sclerophyll forests. You can see them growing on the side of the road.

Further west, Kingaroy, you can find brigalow. Even further west most of the tough desert acacias like mulga will also make a good bow too.
Title: Re: bamboo
Post by: HedgeHunter on May 22, 2020, 07:21:42 pm
Go harvest your own atading dead. Best boo there is. Green or yellow variety.

Title: Re: bamboo
Post by: Rākau on May 24, 2020, 01:32:26 am
cheers for the continued feedback guys. It seems that different boo species react differently in different environments. So i will cut some up and leave some whole and keep an eye on mould.

Ben.A.M. yeah we are in a similar sitcho to you guys in Auz, few of us making bows and we are still exploring appropriate species etc bit we have a few natives that make good shooters. speaking of plum I just harvested 7 pole staves last week from a roadside patch. If you guys have privet over your way you should give it a go, great stuff.

I will be using the boo to back some black Maire which is a native with good potential. very dense and some have used it for bellies before.
Title: Re: bamboo
Post by: Eric Krewson on May 24, 2020, 07:15:56 am
When I have my bamboo dry and have the slats worked down for future bows, it looks like this;