Birch bark for covering composite bows

Your thickness is ok. Hide glue of a thin consistency should do fine.

The important thing is to avoid trapping bubbles during gluing. Warm the sinewed back well before the gluing, and after laying on the bark, press it with a hot clothes-iron.

Chinese bowyers hold that before attaching the glue, you should apply saliva to the sinewed back of the bow. It tastes disgusting :x . I don't know if there is a scientific basis.

Stephen is right.
I want to add that cooking the birch-bark in salty water (5grams of salt within 1 liter water) for one hour makes the birchbark a bit softer and easier to work with.

For the glueing a thin solution will be fine. When the backing is dry I sand it a bit carefully and cover it with a another thin solution of hideglue, after the drying you have to sand it again.

Some weeks later the bark will loose its whitish colour and turn out to look more red or even orange.

A very helpful site for these ancient techniques is: www.nativetech.org run by Eastern Woodland Indians. A search-tool is included.

Michael

Regarding the availability of birch bark: is the birch bark we can harvest from the birch in middle europe / germany suitable for cobering bows? I found it pretty difficult to get pieces of sufficient size.

Whats the best way to do it?

There are different ways of cutting the bark. Chinese bowyers cut it into strips about 3cm x 25 cm and glue it on obliquely at 45 degrees. Koreans use similar strips but glue it vertically. Mongolians glue the strips on vertically, too.

An antique Korean bow I own has the bark in a single piece with the figure parallel to the limbs. A common Qing Chinese bow has the bark figure at about 30 degrees from perpendicular; with the siyahs parallel and grip perpendicular. A finer Qing bow has the bark at 45 degrees meeting at a chevron on the centerline of the back, among other decorations. None of the bellies of these bows is covered, the horn is exposed. On the King Tut bows on which bark figuring can be made out, the figure is perpendicular to the limb circling the entire bow.

I find using hide glue on bark a torturesome experience, as the glue does not soak into birchbark and only adheres at a majic moment of tackiness. I am sure that this could be tweeked, though, through experience.

Thomas' friend on video used rubber glue, if I remember correctly. This works sublimely! and will dry waterproof. But I would like to know if there is a more ancient alternative for a rubbery like glue, such as gum arabic, etc, that was used.

There is a black mastic used on my nicer Qing bow which is used to black out imperfections in the finish of the background of birchbark designs. Does anyone know what material it might be? Does not look to be as hard as lacquer. -j-

I am intending to glue the strips with the dark marks (pores?) running vertically. I think this is the orientation on the Hermitage Moshcheveya Balka bow (the photos are not too clear), it is definitely the orientation used in the Gogops bow.

The strips of bark I have are just long enough to reach from grip bindings to base of siyah. I will use extra pieces for the siyahs and grip, covering the joins with the sinew bindings. I am not sure that I want to cover the whole grip with birch bark as on the original MB bow. I will leave that till last while I make up my mind.

I will try gluing the first strip to the limb with hide glue tonight and see how I get on.

Thanks for the advice

Andrew

Take the bark around the tree. Not on height.
Grain is stronger that way. If it's for only decoration you can take it any way in any thickness.
http://www.bahnhofbredband.se/~wb304054/IMG_7537.JPG
Bark glue on same day it was removed from tree.
If you let it dry you must put in water first.

jack farrell wrote:

But I would like to know if there is a more ancient alternative for a rubbery like glue, such as gum arabic, etc, that was used.

There is a black mastic used on my nicer Qing bow which is used to black out imperfections in the finish of the background of birchbark designs. Does anyone know what material it might be? Does not look to be as hard as lacquer. -j-

Birch bark comes with the perfect glue for attaching it to a bow, waterproof and all. This birch tar is cooked out of the bark using a combination of high heat and little oxygen, (tightly stuffed bark in a metal jar in a fire etc.), so that a black, aromatic tar oozes out. This stuff is the hot glue of ancient birchland inhabitants - a solid mass when cold, but softens upon heating. Forms a slightly elastic, pitch-black, completely waterproof glue layer. Used for attaching arrow points, fletchings, birchbark coverings, making fishing equipment etc. in the Boreal forests since the last Ice Age.

Tuukka

I have attached the birch bark with hide glue. I followed Redhawk's advice and boiled the strips in salty water (this darkens the strips quite noticeably). I applied glue to both surfaces, positioned the strip then bound together. After about an hour, I unwrapped the bow, trimmed the edges and used a heat gun to remove the air bubbles.

Attached is a photo of one limb shortly after attaching the bindings. Anyone have any advice on how to remove dirty fingerprints from the bark?

Tuukka, it would be interesting to find out how stone-age man made birch tar in a low oxygen environment long before access to metal containers, and probably before even pottery.

Andrew

I think, pottery goes in paralell with fire.

Another way would be some embers with a lot of birchbark over it. When it going out there should be some drops of birch tar between the residuals of the bark. But for me there is not enough birch bark to test it...

Tuukka; That is good information. Have you made/used birch tar? -j-

I wonder if birch bark tar remains fllexible for long? The other hot-melt, rosin, needs something soft, such as oil or wax mixed in to remain flexible indefinitely, otherwise it looses its volatiles becoming brittle.

I still have problems with birch bark. No matter how well it looks when freshly applied, it develops cracks and wrinkles when a bow is used a lot. I imagine sanding off the wrinkles and soaking in glue again, as Redhawk suggested, would eliminate the problem, but I can not imagine the ancients doing this. Making the sinew glass smooth helps, but not for long.

Adam

Andrew,

I have got two birch bark pieces but I dont know how to separate the layers from the bark.
The bark is 3 mm thick and there are about 15 thin layers.
Can help?

Tuukka

Just to be clear, you cook the birch bark by its self without water?

matt

Matt,

it?s much more complicated than that. If you want to use birch bark tar for backing bows: that won?t work. Tuukka recommending that glue is a sign he has never done it before because birch bark tar starts becoming soft when it?s exposed to the sun. Birch bark tar is good for fletching arrows, gluing points or hafting knife blades but not for backing bows.

Hartung

Think you for your information, But I don't make bows, I make many different kinds of arrows. And I am interested in seeing how well it holds the tip on. I am thinking it is probly equal to pin pitch. But the sun does not soften it. I though of using it for glueing nock inserts in but if it can be soften by the sun I would not want to do this.

Matt

Matt,

I can?t comment on pine pitch as I haven?t yet done any testing with that stuff.

Birch bark tar is something for say ice age enthusiasts ? like me ;-). It can very well hold a point so that you can kill a deer with it but it?s not designed to be used for repeated target shooting. It is great stuff as long as it is used to its destination.

hartung

So I see that when using it for fleathers you apply it to that whole are of the shaft. The second things is that I believe from the picture that the nock is a insert type maybe of bone? If so it soesn't appear that you used birch tar to glue it in?

Last thing I have been making some bone tips, and people and books have told me that i have to keep the bone head very small to avoid it from beaking. But I notice yours is long and narrow, How has this woked for you. Is this ,If known a typical shaped bone head from your area?

Matt

Matt,

go here to get more infos about the arrow: http://p081.ezboard.com/fpaleoplanet695 ... =398.topic

It is not a typical shaped bone head from my area. This arrow is very light and fast and could be used, in my opinion, for hunting birds. As you said, I?d use shorter bone heads when going for bigger game.

Is somebody who knows how to separate the thin layers from birch bark?

Ginni

I not sure if this is the rightway but last night I scaped the loose parts off then hand sanded the rest down with some 100 grit sand paper, It seemed to work well. I was wondering how that was done myself.

matt

This sound not right...

Thomas said something about the birch bark that the koreans bowyers use, like "the bark is soaked in sea wather for a year", not sure I remember right.
The birk bark from my hwarang bow is very thin, I am sure that is only one layer.

How is made that thin bark?

They came out around 0.23 mm thick. But you are correct with that, In Thomas's book which says: Korean bowyers soak the bark in sea water for one year then it is kept damp.........Before application, it is boiled in salt water for several minutes. If it is boiled in clear water, it turns yellow and if boiled in water with wood ashes it becomes a maroon color, if it is dried in the sun for more than three months, it becomes white.

I just read this book you would though I would have remembered that. Becouse I also found the an answer to a queation I had , was what glue do they use......contact cement that has been thinned with benzene.

I am sure glad you reminded me by mention his name.

Matt

Hartung

I almost forgot, I very much injoyed that link. Its good to see detailed information. but that left me with 2 questions.

1. I have not seen someone use a percent to discribe FOC(FOC 12%).
How do you come to this figure?

2. Is the red and black arrow with the stone point above that yours? I would like to know about the painting process on it.

Matt

Matt,

I determined the FOC because the arrow is composed of to very different materials (grass and wood). Just wanted to see if the arrow was correctly balanced.

More about FOC: http://www.socalarchery.com/Information ... center.htm

The red and black arrow is from Fiddler: http://p081.ezboard.com/fpaleoplanet695 ... =383.topic

Your information about boiling bark in wood ashes is interesting. When you speak about the maroon colour. Do you mean the inner face or the white outer face of the bark turns to maroon? For how long do you boil the bark? Would it be possible for you to post pics of both sides of such a bark boiled in wood ashes? Thanks!

Considering that birch bark was used widely as a backing in areas less coastal, like the central Asian steppes, there has to be another way of preparing it. I have often wondered, like Ginni, how it was achieved and also, with such thin bark, how continuos use of the bow does not cause it to split.

Let me restate this, The information on the birch bark, came out of Thomas Duvernay 's book "Korean Traditional Archery". I myself just started soaking my birch bark last night, Half in salt water and half in fresh water. Fresh water is just a test I, would like some to remain the same color it is now. But as with the picture of the maroon coloring thier is a picture in the book, I would scan it but you can not see the color very well.


Hartung

That was very good information thanks.

Matt

Ginni

You should be able to peel the layers apart by hand with a suitable piece of birch bark. No preparation should be needed before peeling. Any fragments of other layers can be rubbed off using your fingers.

On less suitable pieces the layers tend to tear. I have not determined what makes a good piece of bark, whether it is related to species, size of tree, time of year, etc.

Once thin enough it is quite elastic so will stretch as the bow bends.

Andrew

I was reading about how to make a birch bark canoe a while back, and I read that you should harvest the bark when the sap is flowing to make it easy to remove (I can imagine it being very difficult to harvest bark in winter).