Broken siyah
I've been busy on a Magyar bow lately and got it ready for applying sinew. When I tried to put the siyahs under tension to get a more reflexed shape however one siyah snapped completely. Now, the siyahs are constructed exactly as shown on the attached drawing by Andrew Hall. Breakage occured not along the glue line but tore out a very thin slice of wood just underneath (as marked on the picture), breaking cleanly through the thin wooden core and severing the siyah completely.
I glued it back as well as I could but I am not sure if this bow can be salvaged at all. Perhaps the sinew would provide enough strength to keep the siyah in place? I could also wrap the joint with sinew (which I intended to do in the first place anyway). Still, I have serious doubts about this. If the bow cannot be salvaged, I would not want to waste any sinew on it - though this is not a pleasant thought considering the time spent on the project already. Any advice would be highly appreciated.
A happy New Year (and as few broken bows as possible) to everyone!
I glued it back as well as I could but I am not sure if this bow can be salvaged at all. Perhaps the sinew would provide enough strength to keep the siyah in place? I could also wrap the joint with sinew (which I intended to do in the first place anyway). Still, I have serious doubts about this. If the bow cannot be salvaged, I would not want to waste any sinew on it - though this is not a pleasant thought considering the time spent on the project already. Any advice would be highly appreciated.
A happy New Year (and as few broken bows as possible) to everyone!
Tomaz
Sorry to hear about the breakage. How much force were you putting on the siyah to increase the reflex? I have always been quite gentle with my forced reflexing, as you are bending the bow the wrong way with respect to the materials and construction.
How is the grain orientation in the core? Did the break follow the grain through the core? Unless you were using a large amount of force or the break followed the grain in a ring-porous wood like ash, I would start to get nervous about the condition of the core wood.
I have not really got any suggestions for repair. I can't think of anything other than gluing it back on and well backing and wrapping with sinew (make sure the backing is dry before wrapping, otherwise the backing will shrink out from under the wrap and loose the tension). Good glue joints are supposed to be stronger than the wood and the sinew should be taking the tension load, but it never fun shooting a bow when you are worried about it falling apart. Take care.
It is possible to soak off the sinew backing and reuse it if a bow fails.
Have a happy New Year
Andrew
Sorry to hear about the breakage. How much force were you putting on the siyah to increase the reflex? I have always been quite gentle with my forced reflexing, as you are bending the bow the wrong way with respect to the materials and construction.
How is the grain orientation in the core? Did the break follow the grain through the core? Unless you were using a large amount of force or the break followed the grain in a ring-porous wood like ash, I would start to get nervous about the condition of the core wood.
I have not really got any suggestions for repair. I can't think of anything other than gluing it back on and well backing and wrapping with sinew (make sure the backing is dry before wrapping, otherwise the backing will shrink out from under the wrap and loose the tension). Good glue joints are supposed to be stronger than the wood and the sinew should be taking the tension load, but it never fun shooting a bow when you are worried about it falling apart. Take care.
It is possible to soak off the sinew backing and reuse it if a bow fails.
Have a happy New Year
Andrew
Hi Tomaz, I?m almost sure that you have sawed this siyah without taking care to follow the grain and growthrings of the wood.
I would go further than Andrew: make a new siyah, clean the joint and glue the new siyah to the core again.
As Andrew told you, it is really nerving to shoot with an "anyway repaired" siyah.
Happy new year, Michael
I would go further than Andrew: make a new siyah, clean the joint and glue the new siyah to the core again.
As Andrew told you, it is really nerving to shoot with an "anyway repaired" siyah.
Happy new year, Michael
Thanks for the feedback. To clarify, the siyah is a two-piece spliced construction. The thin ash core (4mm) was steamed and had another piece of wood glued to it as reinforcement. I may have applied too much force trying to reflex the bow more than it would readily bend actually. The break occured at the very end of the base core, right where the growth rings run at a very slight angle (but in no way completely through the core). It lifted up a clean little chunk of wood along the growth line but left the rest of the core intact. This probably wouldn't have happened with maple.
Anyway, I backed the bow and wrapped the joints yesterday. I don't have any real expectations, I'm just curious how it's going to turn out. It is going to be a light practice bow anyway so I guess it all depends on the glue and sinew now.
Anyway, I backed the bow and wrapped the joints yesterday. I don't have any real expectations, I'm just curious how it's going to turn out. It is going to be a light practice bow anyway so I guess it all depends on the glue and sinew now.
Tomaz,
I know it is too late, but did you consider putting the siyah reinforcement on the belly side of the core rather than the back side?
I know it is too late, but did you consider putting the siyah reinforcement on the belly side of the core rather than the back side?
I haven't really thought of that, Bede. Do you think it would make a stronger siyah?
I think it might. It is how the Khotan bow was constructed in simplified form. Of course, the other advice that has been mentioned should be followed too. Once the sinew is on your bow becomes more robust, but when you are working with the core and the horn alone you need all the structural integrity you can get.
I am not as accomplished as some of the people here so I tend to follow advice in bow making rather than give it. My comments are more observational than from experience.
I am not as accomplished as some of the people here so I tend to follow advice in bow making rather than give it. My comments are more observational than from experience.