I was wondering which is better: bending in some reflex, than adding more reflex when glueing the horn (e.g. by tieing the tips together or clamping them in a form), or bend the full reflex and glue the horn without adding further reflex?
I think that the first method is better for the wood because there is some initial tensile strain on the compressed part, which reduces the overall compressive strain (I suppose). But I am not sure about the shear stresses in the glue. Any ideas?
Daniel
redhawk
Usually the reflex in hornbows is built by the grown reflex of the horn and the impact of the sinew- backing. The wooden core is a frame.
I?ve never heard something about glued in reflex in hornbows.
Glued in reflexes in 2 lam- wooden bows had been very common since D. Perry has published it. But D. Perry himself published a better working method of glueing a bent slat with a straight slat. That?s what I would prefer.
The first Perry- reflex produces to much stress(shearing forces) on the glue- line.
But if you have a closer look to actual selfbowery, you?ll see straight bows with heat- treated bellies, maybe a little reflex.
It seems to be more and more obvious that reflex is a much over- estimated design for wooden bows.
Michael
JJ
Korean bowyers bend the cores to a circle before glueing the horn. But I think this can only be done in very thin, extremely elastic bow designs. As Daniel said, it puts enormous stress on the glue line. Glue lines in Korean bows are sometimes 2 mm thick, by the way...
JJ
Daniel T.
I read that traditionally thicker cores were bent by cooking and then the horn was glued on. The thicker core forced the horn to take on the shape of the core.
I had the core clamped at the tips between two slats. Here is a picture:
The one in the picture was glued with epoxy. Reflex can be added by clamping the tips at a shorter distance (This will reflex the section near the grip because the core has no width or thickness taper at this point). Or by cooking and bending to the thus reached reflex in the first place. Then the horn is glued to match the shape of this core. The final shape will be the same for both constructions.
Michael, I did not know the bent slat/straight slat version, but both versions you described are similar to one of the procedures I ask about. I have been thinking about the differences in shear stresses between both versions, but I didn't reach a conclusion.
JJ,
I don't know much about the construction of korean bows, I dare not comment.
Daniel
jkekoni
Korean bowyers bend the cores to a circle before glueing the horn. But I think this can only be done in very thin, extremely elastic bow designs.
Also it should be remembered that these bows have bamboo cores, not wood cores. Bamboo bends more than wood.
I have actually a releated project. I may publish more details later...
redhawk
jkekoni, you know the Paleoplanet- site, there are lots of 2 wood- lams too Not always boo.
But as I mentioned, the times of reflexed bows seem to be gone. Heat- treating is the thing.
Korean bow cores before glueing on the horn... Workshop of Kim Park Young 2008.
JJ
wencheh
If you use gelled strip method for sinewing like Korean bower, the core must be curved originally, that's what I heared.
jkekoni
The cores in the picture look like wooden ones, not bamboo. Are there several korean bow styles?
JJ
It?s bamboo with acacia siyahs , as usual.
JJ
Orda Khan
Acacia? I thought the traditional Korean bow has mulberry siyahs and oak handle section.
What is the approximate thickness of the bamboo? It looks quite thick.
JJ
Today mulberry is hard to get for the Korean bowyers. They use Acacia (Robinia Pseudoacacia) instead since many years. The bamboo core is quite thick (appr. 1 cm) but will be reduced after glueing on the horn.
JJ
Dusan
I am proud that i have superb shooting korean hornbow from master Kim Park young. Interesting thing is that siahs look like bamboo -no acacia. I know that acacia is usualy material.
I think taht korean stile reflexed core was because his pregeled sinew plate. Sinew dont worked dramaticly like if you soaked sinew and glued imediately in core. Adam tell about this in your book very clearly.
I like this method more than others because you prevent your core and horn cracs and delamination, but you must know very wel all working problems about gluening process.
Old turkish sources say about similar work in turks bowyears.
Its look like modern lamination proces. You buy laminate plate and glued in bowe core. Sinew gelled plate look very similar... :D
Daniel T.
JJ wrote:
Today mulberry is hard to get for the Korean bowyers. They use Acacia (Robinia Pseudoacacia) instead since many years. The bamboo core is quite thick (appr. 1 cm) but will be reduced after glueing on the horn.
JJ
This tree is called Black Locust. I was told it's too oily for good glueing.
Daniel
PjSingh
Black locust and acacia are 2 different woods.
Dusan
Yes. Blac locust is this wood. And if you Daniel good heating him and cooking. Oiling was not a problem. Thats mi experiences.
Patrick Menzies
Keep in mind that Black Locust is "false" acacia. It resembles true acacia but is not the same thing. It's an American wood that seems to be extensively planted overseas.
Dusan
In Europa we know this :lol: Because its no original our wood , we can cut him everywhere.Locust grow very quickly. I think that same situation is in Korea. From locust you can make good flatbow too(bout 60-80 lb) Iuse him vith sucesfull for siahs.
Daniel T.
Wow, I didn't know that, Dusan. Now I have a nearly endless supply of very low defect core wood in walking distance from my parents' house. :D
I think I will have to visit them soon and bring my saw.
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