Plant Fiber Backing Info Needed.

[Prarie Bowyer]

Ramie doesn't sound like a good material for backing bows.  I wouldn't use it personally because of its low elasticity.
From Wikipedia: 
Because of its high molecular crystallinity, ramie is stiff and brittle and will break if folded repeatedly in the same place; it lacks resiliency and is low in elasticity and elongation potential.[5]

[5] Kadolph SJ, Langford AL. Textiles (9th ed.). Upper Saddle River, NJ: Prentice Hall; 2001.

Interesting.  It is listed as China Grass in TBB vol. 1 (under backings) and vol2(natural strings).

Here is a question, what is the most elastic plant fiber?

[burn em up chuck]

    processing bamboo fibers maybe a factor to consider, but remember bamboo is a powerful backing.
    at harbor freight i found flax twine. maybe a source.

                                                                            chuck

[Prarie Bowyer]

most of the bamboo raimie is made from the inner portion.. the strength is in the outer portion.

[JackCrafty]

As far as I can tell, the most elastic plant fiber is coconut hair from unripe coconuts or White Coir.  The unripe distinction is EXREMELY important because the brown stuff on coconuts at the store is useless.  (Look at the Elongation at Breakage %.  Wood is less than 2% if I remember correctly.)

The best overall fiber, in my opinion, is sisal or agave fiber. The TBB states that this is one of the weakest fibers but I have found this to be completely false (not the only falsehood in the TBB).  The worst quality sisal will outperform the worst linen fibers (in terms of elongation before breaking).  I like to look at the worst properties of the fibers because these are what we usually get from the store or commercial sources.

I have attached a chart for your inspection and you can interpret the data as you wish.   

Source: http://www.indiantextilejournal.com/articles/FAdetails.asp?id=3732

[Prarie Bowyer]

Cool!  Are you getting sisal from the cord?

How are you applying it?

And the coir?  Where do you get that?  Seems like it would be hard to overpower a bow with that.

Applied like sinew in tb2-3?

[Prarie Bowyer]

Coir can be found marketed as "hop twine".   But looking at the stats above. I think you are correct,  sisal may be the way to go.   Are there similar stats for sinew strength and stretch?   I'm wondering if there is an plant alternative.


I'm reading the tbb on backings and thinking about weaker woods like mulberry, hack berry etc.

[JackCrafty]

I apply fiber backing in the same way as sinew, with Titebond or hide glue.  I get sisal from thick twine that I order online.

I don't know where to get good quality Coir fiber but a quick google search yielded a couple sources for coir rope with the cheapest being ebay.  I've never used Coir so I can't give you any advice there.

[Prarie Bowyer]

Do you cut it to roughly sinew size lengths or do you leave it as long as possible?

How do you determine the thickness or are you just putting one layer as thin as possible?

[4giveme]

Prarie,
I would definitely leave the fibers in as long I could get. I mean then it's less seams that I have to deal with. That's IMO anyway....
Tommy

[JackCrafty]

Yep, leave the fibers as long as possible.  And build up the layer to and average of 1/16" (after it's dry) as a minimum.  Build up layers near the handle but leave the tips thinner than 1/16".  A cloth backing is only about 1/32" of an inch thick at the most, so you don't need much.

[dbb]

I found this searching for ramie.Native to East Asia and commonly known as China grass, ramie (Boehmeria nivea) is a flowering plant of the nettle family.
I know Nettles make a fair bowstring but is the same low stretch property that makes a good string what makes it less good for backing?

[toomanyknots]

I found two sections on plant fibers in the TBB.  There is a concern that Flax while strong as nails could possibly overpower a bow?

I've used nettle fiber (similar to flax with little to no stretch) and it is like bamboo x 100, it will really crush the belly if you don't have some good bowwood. One thing I would recommend is do NOT use titebond for the glue, hide glue is the way to go. Titebond was a horrible pairing with a fiber backing I did, it was hard to work with, heavy, has no spring back or reflex when drying. In fact I think it is just as bad to use with a sinew backing, and I can never understand when people will sinew back with titebond.

[toomanyknots]

What TimBo said. 
sinew is really good for only one thing from an efficiency standpoint--keeping short bows alive.
I have a few miles of Jute that I am going to try as backing asap.

(Fair warning, the following is just my opinion and is not meant to be taken too awful seriously or personally in any way, )

With all due respect, sinew is resilient more so than rubber, making it recover it's original condition after being stretched in tension much much more than any other backing. This absolutely adds to performance when used effectively, typically by reflexing the unstrung bow, adding significantly to the early draw weight (while smoothing out the force draw curve), and in effect transferring more energy to the arrow than a bow with less early draw weight / a more uphill force draw curve. And although other materials can of course be used to the same effect via perry reflexing in a laminate, sinew is the only backing material (although I think wood backings will to a degree) that will actually pull itself back into reflex, lessening the responsibility of the belly to regain the originial unstrung profile. To say that the added weight of sinew brings any sinewed bow to a disadvantage off rip is ignoring 1000s of years of bowyers effectively and efficiently using sinew both for hunting and war, from one continent to next, from hemisphere to the other.

[Prarie Bowyer]

I wish there was an alternative to sinew that workes the same. 

It is working with the hide glue that has me hesitant to do any sine wing....but I guess it is coming.

Interesting that tb didn't work well.  Did you use 1 or 2.

[JackCrafty]

Try the Titebond with the sinew on a thin scrap piece and bend it (type 1 and 2).  It won't pull the piece into reflex, that's true: only hide glue does that.  The greatest drawback with hide glue is the drying/curing time.  It can take weeks or months.  Titebond will cure in a few days.

Anyways, bend the test piece and watch how it snaps back.  It will snap back quickly at first and then very slowly go back to it's original straightness (unless you caused some set).  Try not to cause any set at first.  Then bend it until it brakes.  The sinew/titebond combination will bend and stretch A LOT before it breaks (if it does).  The wood will break and collapse way before the sinew is affected.  That's why some people like it.  That and the fact that TB 2 is water resistant.