Bark cordage

[wildranger]

Hi all, I just have a few unanswered questions that have been nagging me for a while with regards to producing cordage from bark fibres. If anybody could help me out here it'd be fantastic. Firstly, is it generally the thin cambium layer or the inner bark that is used to make string (I think it is but just wanting to confirm this)? What is the best method for separating the cambium layer from the inner and outer bark? Just scraping down to it or is there a quicker way? And finally, out of wych elm, lime, willow, sweet chestnut and others, is there any data out there on their tensile strengths because it'd be good to have an idea of their relative strengths. Thanks

 

[Toddy]

It's the inner layers, plural, that you want.
I'm no expert, but if you soak the inner bark in water (it'll stink to high heavens, basically it's an anaerobic bacterial decay that sets in) the stuff that holds the layers together rots before the layers do. You can use whole bark, but I found it quicker and cleaner to use peeled bark.

Somewhere there's an on line copy of a Victorian book that gives the tensile properties of ropes. The reckoning is the rope made from small leaved lime is the strongest natural rope from native trees in the British Isles.

My link's dead surely someone else will have it ?
If I come across it soon, I'll mind and post it here.

cheers,
Toddy

 

[wildranger]

Awesome Toddy thanks, so retting separates the layers, nice one. I'll have to try retting, still haven't gotten round to it. Do post that link if you come across it because that'd be really interesting!

 

[redneck]

If it's ok by the mods, I did a quick tutorial on my blog about lime bark cordage, and the links are below,mods please remove them if this is not permissible

http://buzzardbushcraft.blogspot.co.uk/2011/08/lime-bark-cordage.html

http://buzzardbushcraft.blogspot.co.uk/2011/10/finally-finished-lime-bark-cordage.html

 

[Toddy]

No complaints from me, I love seeing how other folks make things
Please check out the reciprocal link thing though, and everything's sweet.

cheers,
Toddy

p.s. Just had a look, and it's good I've never managed it in less than six weeks and that was it sitting in a warm sunny corner of the garden, I reckon your eight weeks was spot on too.
I did abandon some when I had to go away from home for work, and it literally soaked for four months. The stench on my hands as I stripped out the layers was truly dire, but the bark just seperated out like sheets of lasagne. Brilliant
Made really good cordage too.

The colour thing; flax that is river retted is whiter than flax that is dew retted. Don't know if it's relevant, but it might just be more oxygen affecting which bacterial action gets more efficient

Thank you for the link
M

 

[redneck]

Thats very interesting about the colour of flax after it's retted in different ways, thanks for that!

 

[Toddy]

It can be quite interesting seeing how different folks process the bast fibres

This is a British link (rare now to grow and process, flax here) and it shows the colours from unbleached, undyed, ready to spin, French, Cotswolds and Dutch flax.

http://www.flaxland.co.uk/projects.html

I know that with willow bark I can get almost black sometimes, usually a kind of rust, but I have had nearly white too.
It depends, is the only answer I can give. Water, bacteria, the temperature, how much tannin is in any bark......just so many variables.

cheers,
Toddy

 

[AussieVic]

I know you're asking about the relative strengths of the fiber, but in practice your skill in making the cordage will play a significant role in the strength of whatever is made – until you become an expert ! Even then, you will need to know what thickness represents what strength.

Can I suggest you start with whatever is easiest for you to get hold of, and practice with that. You can always make a thicker cord, to make it stronger.

To really find out how strong it is you need to test it. I’ve used lengths of cord to suspend weights (ie jerry cans) to test their strength. Tie one end to a support and the other to the jerry can handle and see if it holds or breaks.

 

[wildranger]

I know you're asking about the relative strengths of the fiber, but in practice your skill in making the cordage will play a significant role in the strength of whatever is made – until you become an expert ! Even then, you will need to know what thickness represents what strength.

Can I suggest you start with whatever is easiest for you to get hold of, and practice with that. You can always make a thicker cord, to make it stronger.

To really find out how strong it is you need to test it. I’ve used lengths of cord to suspend weights (ie jerry cans) to test their strength. Tie one end to a support and the other to the jerry can handle and see if it holds or breaks.

I agree with you that the skill in making is very important. However, I'm hoping to make a bark bowstring and since bowstrings are under a huge amount of strain, I really want to be using the strongest available fibres in addition to skillfully twisted cordage to ensure success! I know it'll need to be thicker than a nylon string, I'm estimating that 5mm thickness, tightly twisted 2 or 3-ply should hold up for a 45 lb pull, what do you reckon? The good thing is that doubling the thickness of a string, quadruples the breaking force!

And yea, I'll have to do my own tests to get some real data on this..

 

[Toddy]

Oetzi's bowstring was made of two ply bast fibre. Lime bast to be precise. It varied in thickness from 3.5mm at one end to 7mm at the other end which was knotted. About 2m long iirc.
Very evenly worked from what I read. The arrows that were nocked had a 4mm space.........so the reckoning was for a 45 to 50lb bow.

The bow, made of Yew, seemed of a type very similar to those of the MaryRose, but there was a debate about whether the bow was actually finished or still a work in progress.
The archers of the MaryRose pulled 100lbs, but they trained constantly to the extent that it was possible to differentiate the skeletons of archers from sailors from the asymetrical development of the muscle attachments to the upper arms.
The MaryRose bows would have had linen bowstrings.

Interested to hear how you get on

cheers,
Toddy

 

[wildranger]

Oetzi's bowstring was made of two ply bast fibre. Lime bast to be precise. It varied in thickness from 3.5mm at one end to 7mm at the other end which was knotted. About 2m long iirc.
Very evenly worked from what I read. The arrows that were nocked had a 4mm space.........so the reckoning was for a 45 to 50lb bow.

The bow, made of Yew, seemed of a type very similar to those of the MaryRose, but there was a debate about whether the bow was actually finished or still a work in progress.
The archers of the MaryRose pulled 100lbs, but they trained constantly to the extent that it was possible to differentiate the skeletons of archers from sailors from the asymetrical development of the muscle attachments to the upper arms.
The MaryRose bows would have had linen bowstrings.

Interested to hear how you get on

cheers,
Toddy

Fantastic information thank you, and so timely as I was just wondering today how Otzi's lime bast bowstring was plyed up! I'm going to try willow bark first so as to save myself the wait with the retting process. There's goat willow around here so I'll try that, but the challenge will be to find a nice long piece to save myself splicing in, as I want to keep it as neat as possible and avoid weakening it. What do you think? Willow might just do the trick?

 

[Toddy]

Hmmm
It's horses for courses really.
Willow cordage is really strong when it's wet. There's a coil of willow bast rope reckoned to date to the Bronze Age still attached to a sunken Danish logboat, and it's still recognisably willow bast cordage It's never dried out y'see.
However, I don't know how strong it is with the flex and pull, and release, of a bowstring.

Lime bast however, we know was used for bowstrings.......and it's not just using what you have, because mind Oetzi's bow ? it was made of Yew. To this day Yew is a preferred wood for bows because it's just so good at it's task. It comes to mind that a people who'd sussed out the bow probably sussed out the string too

It's a good time to peel willow though and goat willow is sweeter than the rest to work

cheers,
Toddy

 

[AussieVic]

I haven't used much willow, but because you can try it straight away it would be great to give it a go, even if it won't stand up to the bow string job, you will get an appreciation of what you're looking for

As Toddy says, a bow and its string need to put up with more than just the "pressure" of the pull, that twang on release may knock around some materials quite badly.

Back to your OP re the bark, I’ve found that the outer layer of bark is easily removed by scraping the bark, while its still on the stick, with the back of a knife. This is a relatively quick process; then peel the bark.

Here are some pics – yes the first one is a bit of a scrawny stick, but you can see what’s happening. Once its cleaned up, the bark should easily pop off
This is actually an acacia, but (from memory) willow is very much the same

 

[Toddy]

Good illustration thank you.

Hear, while I mind, Off Topic, but..... There's a lady in Scotland who makes the most beautiful organic tanned hides....deer and sheep, hair and wool on, and all she uses is ground acacia bark. The skins are washed, the gunk cleared off the back and then the hides are soaked in the acacia bark tanning liquor.
They come out soft, supple, non allergenic, baby skin safe, undyed, and really the best I've ever seen

cheers,
Toddy

 

[dwardo]

Its usualy best to go for atleast a few X`s your bows weight for the strength of the string. Pretty useless at cordage besides the odd couple of feet for a project but there are lots who do use natural filbers or gut or sinew.
Personaly if i have made a nice bow i dont want to risk it blowing to bits due to a failed string so i cheat and all mine are Dacron.,

 

[AussieVic]

Good illustration thank you.

Hear, while I mind, Off Topic, but..... There's a lady in Scotland who makes the most beautiful organic tanned hides....deer and sheep, hair and wool on, and all she uses is ground acacia bark. The skins are washed, the gunk cleared off the back and then the hides are soaked in the acacia bark tanning liquor.
They come out soft, supple, non allergenic, baby skin safe, undyed, and really the best I've ever seen

cheers,
Toddy

Yes, not wanting to stray too far, but ..... when I boil the bark, a very beautiful earthy toned liquor is produced. I haven't dyed anything, but it looks like it would be very good.

Australian acacias have long been prized as a source of tannin, especially for leather, and a very large industry used to exist for it harvest, preparation and extraction.

Anyone interested in dying would be well advised to have a look at it.

 

[bandel4]

Hi...I am from Malaysia and obviously the trees here are different but I thought I'd share how I have seen it done.
Below is a video I posted sometime back on Youtube (mod please remove if this is not appropriate).

[video=youtube;7t_pMp5X4Z8]http://www.youtube.com/watch?v=7t_pMp5X4Z8&list=UU18E YArvvBvMrVhNrYgGZeQ&index=5&fe ature=plcp[/video]

Hope you enjoy it

 

[Toddy]

Bandel4, thank you that was a fascinating film to watch
I love that technique for removing the inner bark, and am wondering if it would work with our willow and lime bast too.
Need to try it

Thank you for the link, and if you ever meet Stem again, thank him for showing us how

cheers,
Toddy