Korean bow exercise
I am a new (2 month) owner of beatiful original Korean traditional copmpsite bow. Before this super thing i working and shooting vith bigger mongolian , chinese, and "like" turkish bows - mi work pieces. I thoght that i know - not all- but most of how exercise and hot tilering composit bow , but working vith this little " life worm " is big experience to me . Nobody here dont tell nothing close about Korean bow konstruktion , but maybe we can talking more detailed about this very importent and interesting theme. Heating and working vith bow arms you not only tillering every arm separetely , but you must saftely screw each end of siahs - because if your string dont sit in right place and angel , your bow can explode... I heatworking vith mi new bow 2 month , and , he can surprised me every time vith new position of his arms , or siahs. Every time is nev humidity , new temperature - big schul for me . Have you guys , any experiance vith this interesting and importent part of composite bow life ?
Watching Korean bowyers and archers, it seems to me that they mainly use body heat to warm the limbs. Most of the damage I have seen on old bows resulted from inappropriate heating with an external source.
Body heat ? You meen hand , chest /or breast / ..? No. Its must be seriouz heat from charcoal stove or modern elektrik variant. But very carfuly, one mistake and you damage "cooking" sinew layer. Its very importent vith every tipe of composite bows , but mi experience vith Korean thiny devil is most problematic. Maybe vith litlle turkish flytbow too, but turkish siahs help string sit in arms . Korean bow have only very thiny wood line in flat siah and relativly long, thin and "dancing" arm. His "kasan" is working unlike turkish bow. In turkish bow "dancing" 31-33 cm working "wider"-3-3,3 cm arm. In korean bow 35 -38 cm 2,5 -2,8 cm wide working arm. Have anybody praktice opinion ?
This year I had the opportunity of working with a Korean composite bow. It had a twist that was causing problems. You only heat the horn and not the sinew. You do it slowly and do not let it get too hot. It must feel hot to the touch, but do not let it discolour.
The more time you take. the safer you will be.
Gentle pressure and careful adjustment works.
The more time you take. the safer you will be.
Gentle pressure and careful adjustment works.
Thank you Bede, i will. But you maybe wrong in heating site of arm. In my knowledge (all Youtube videos, Mr. Duvernays tape etc.) you must heating sinew . I mean this part of exercise- plastic modeling of each arm- is relatively easy. Most secret for me is precise modeling tips vith string bridgis -angel of arms .This must be working vith high reliable. Another question is ideal humidity -in central Europa- . If i leave bow 1 or 2 weeks out of heat box in tempering room (23 ?C) he lost very of hes strenght and is very "playable" before heating.
I spent several hours in a Korean workshop and watched the master and apprentice working on bows. The workshop had a window to the shooting range and the shooters would present their bows and the master would string and tiller the bow.
It was truly scary watching them work these bows, like a Turkish massage, very intense. The bow was heated over an electric stove, sometimes worked on a low workbench on the floor, and then bent with foot and hand.
What they spent a lot of time doing was to make the upper limb and kasan into a straight line. As each limb was finished a rope loop was put over the end at the kasan to keep it from expanding.
I have the impression that a Korean bow might require this treatment each time it is shot. Shooters keep their bows at home or the master kept them in a dry closet. The heat was at 25 degrees but with no humidity.
The total drying time for the sinew on a new bow is 30 days. -j-
It was truly scary watching them work these bows, like a Turkish massage, very intense. The bow was heated over an electric stove, sometimes worked on a low workbench on the floor, and then bent with foot and hand.
What they spent a lot of time doing was to make the upper limb and kasan into a straight line. As each limb was finished a rope loop was put over the end at the kasan to keep it from expanding.
I have the impression that a Korean bow might require this treatment each time it is shot. Shooters keep their bows at home or the master kept them in a dry closet. The heat was at 25 degrees but with no humidity.
The total drying time for the sinew on a new bow is 30 days. -j-
Thank you Jack , for your opinion , but i need moore than you see in workshop. I mean , fue thing is incorect i your post. First - limb "samsami " and kasan- "mopso" is finaly not in straight line ! When i know first time about it , i was very surprise too. Archer heating ang plastin each limbs in slightly angel . String must bee closer to right side - arow place. Second- in head box must be 30-35 ?C ! If your head box working good , you don?t exercise your bow everyday - if you shoot everyday. Only if you shooting vith long time period ,or you hav not right working Heat box (like me...) you must "training" vith your bowfriend every time :twisted: But i do it vith joy, because its very interesting . But i need more opinion from archer who working longest time vith korean bow. Its like discovery new space :)
Bede , i think you have more experience vith turkish composites. How about heat tillering vith this bows ?
Dusan,
I had a problem with the bow I took to America this year. I tried the Korean techniques on it before I went on to use them on the Korean bow. I found the Turkish bow was easier to work with because the twists were smaller and it was easier to line up the curves.
I gently heated the horn until it was very warm to the touch. The limbs were flexible then though they are very stiff when cold. After correcting the twist, I tied the bow with leather strips to keep the curves between tithe two arms even and let it cool for about 30 minutes. Then I gradually drew it watching the tips and arms for twists. Then I let it set for another 30 minutes without bindings to see if the limbs would stay even.
It stayed stable after re-bracing. I used it for the next few weeks.
I had a problem with the bow I took to America this year. I tried the Korean techniques on it before I went on to use them on the Korean bow. I found the Turkish bow was easier to work with because the twists were smaller and it was easier to line up the curves.
I gently heated the horn until it was very warm to the touch. The limbs were flexible then though they are very stiff when cold. After correcting the twist, I tied the bow with leather strips to keep the curves between tithe two arms even and let it cool for about 30 minutes. Then I gradually drew it watching the tips and arms for twists. Then I let it set for another 30 minutes without bindings to see if the limbs would stay even.
It stayed stable after re-bracing. I used it for the next few weeks.
Thank you Bede, this is close to korean way . You confirmation my idea , about easiest tillering turkish bows. This korean thiny beast is like modern superb cars. Pretty, speedy ,super dizain , but in real life very problematic. When i see oldest fighting and hunting korean bows its visible widest mopso/kasan/ vith thin comb like residue turkish non working kasan and robust siah.Its more stabil , i mean.
But heating horn ? From who you have this information ? All mi experiencis talk about heating sinew site.And praktic logic is same. If you have strung bow ( and you cant tillering unstrung) , you can not safety heating horn - because string .
But heating horn ? From who you have this information ? All mi experiencis talk about heating sinew site.And praktic logic is same. If you have strung bow ( and you cant tillering unstrung) , you can not safety heating horn - because string .
Dusan: Actually I am not offering my opinion, just reporting on what I saw.
Here is a photo of the #1 bow maker in Korea sitting in front of his drying box. The digital readout on top is 24.5, bottom 26.3. It is not a heat box but a box of low humidity. I was able to photograph the straightening process. Good luck, Jack
Here is a photo of the #1 bow maker in Korea sitting in front of his drying box. The digital readout on top is 24.5, bottom 26.3. It is not a heat box but a box of low humidity. I was able to photograph the straightening process. Good luck, Jack
Thank ypu jack. Any information is super. Mi source is Mr. Duvernays?s yuotube video and Skype talking vith korean friend.
Dusan:
Keeping the bow in the hot box may be risky at this time of year. The ambient humidity is now dropping, since the rooms are heated for the winter. This applies to Eastern Europe as well. It means the bow may become too dry and the materials too brittle. This certainly improves the performance and increases the draw weight, but is risky. I suggest to use the hot box rather in the summer/fall, not in winter.
The Korean bows are indeed very difficult to stabilize, due to the reflex in the grip plus the relatively low draw weight (50-60lb) and the thin, floppy limbs as the consequence. The other factor is the flexibility in the siyahs. This is why the bowyers tiller the siyahs straight - it reduces the tip angles and increases the brace height for stability.
Heat is often required for corrections. In case of bows covered with birch bark or leather, it is better to heat the horn side (as Bede said makes the job more effective). For un-covered new bows, the sinew can be heated, but heating horn is still more effective, because horn is a better conductor of heat.
It is rather obvious the bows should be corrected when not stressed - when not-strung, because stressing the hot materials causes string follow and the loss of performance. It is sometimes necessary for new bows to make corrections when strung, but should be avoided for finished bows.
I would not worry at this point about the position of the string - whether towards the arrow side or not. Once the tillering is done and the bow is stable, one can always reverse the limbs to have the string closer to the arrow side. This position can still change during shooting anyway, depending of the individual method of holdin the grip and release.
In any case patience is definitely needed.
Adam
Keeping the bow in the hot box may be risky at this time of year. The ambient humidity is now dropping, since the rooms are heated for the winter. This applies to Eastern Europe as well. It means the bow may become too dry and the materials too brittle. This certainly improves the performance and increases the draw weight, but is risky. I suggest to use the hot box rather in the summer/fall, not in winter.
The Korean bows are indeed very difficult to stabilize, due to the reflex in the grip plus the relatively low draw weight (50-60lb) and the thin, floppy limbs as the consequence. The other factor is the flexibility in the siyahs. This is why the bowyers tiller the siyahs straight - it reduces the tip angles and increases the brace height for stability.
Heat is often required for corrections. In case of bows covered with birch bark or leather, it is better to heat the horn side (as Bede said makes the job more effective). For un-covered new bows, the sinew can be heated, but heating horn is still more effective, because horn is a better conductor of heat.
It is rather obvious the bows should be corrected when not stressed - when not-strung, because stressing the hot materials causes string follow and the loss of performance. It is sometimes necessary for new bows to make corrections when strung, but should be avoided for finished bows.
I would not worry at this point about the position of the string - whether towards the arrow side or not. Once the tillering is done and the bow is stable, one can always reverse the limbs to have the string closer to the arrow side. This position can still change during shooting anyway, depending of the individual method of holdin the grip and release.
In any case patience is definitely needed.
Adam
Thank you Adam !
Many real and usefull information.Because winter and humidity is low i think too that heat box no needed, but when i leave bow in tempering(23 ?C) room and strung him -oups- arms is very playable and lost very from his strenght. I have advice from korean master who make this bow- in winter only training vith heat treating and corecting arms, no shooting . String and his right position - this is advice from mi korean -practice archer friend. This is not about string , this is about angel of arms , like he said. Arms must be corected in grip sectin slightli in right angel and at the same time precisly watched in siyahs . String must tuched string bridges in center line.Be conected vith this, how i can working in arms vith unstring bow ? And once is bow string you can not heating horn site... Its terrible. Maybe because this in all pictures and in all videos koreans heating sinew site (?) . When i was working vith mi other not very C bows i heating horn and sinew site paralel , no needed strung bow. No problem vith control arms angel etc. But vit full C circle unstrung tilering look like impossible .
Another qustion is shooting technik. I notice that thiny limbs react in any move left hand who hold the grip. Its new for me . Holding hand must be like stone , or on the contrary hold very loose ?
Adam , how you have place your bows ? How humidity and temperature is ideal , from your experiences ?
Many real and usefull information.Because winter and humidity is low i think too that heat box no needed, but when i leave bow in tempering(23 ?C) room and strung him -oups- arms is very playable and lost very from his strenght. I have advice from korean master who make this bow- in winter only training vith heat treating and corecting arms, no shooting . String and his right position - this is advice from mi korean -practice archer friend. This is not about string , this is about angel of arms , like he said. Arms must be corected in grip sectin slightli in right angel and at the same time precisly watched in siyahs . String must tuched string bridges in center line.Be conected vith this, how i can working in arms vith unstring bow ? And once is bow string you can not heating horn site... Its terrible. Maybe because this in all pictures and in all videos koreans heating sinew site (?) . When i was working vith mi other not very C bows i heating horn and sinew site paralel , no needed strung bow. No problem vith control arms angel etc. But vit full C circle unstrung tilering look like impossible .
Another qustion is shooting technik. I notice that thiny limbs react in any move left hand who hold the grip. Its new for me . Holding hand must be like stone , or on the contrary hold very loose ?
Adam , how you have place your bows ? How humidity and temperature is ideal , from your experiences ?
The advice from the Korean friend may not apply to your situation, because the climate could be different. In a winter-heated house (like for us), humidity can drop even to 10-30% RH (relative humidity). Now, if a bow thus dried is kept in the hot box, its moisture content will drop even more. As I said the materials become brittle. At the same time permanent corrections in the limbs become more difficult, because at the lower moisture content the materials require more heat to plasticize. At a higher moisture content less heat is needed for corrections.
Measure your RH in the room: if it is around 40 to 60%, the limbs will always be floppy as they are and there is no use to fight it. You want to shoot the bow in normal conditions like that outside anyway and the bow was made for these conditions. If above 65%, then maybe wait a couple of weeks for the room to dry-out as the heating season progresses.
I keep my bows at no less than 30%RH and use a humidifier in the winter if needed.
As to tillering:
There is no need to obsess about the shape of the limbs at the grip now. I suggest to warm the siyahs (only the siyahs) when the bow is un-strung, then string it and see if the siyahs are straighter and the bow is symmetrical. Wrap the limbs with something to hold them in this position (as Koreans do) and wait for a couple of hours to cool, checking every 1/2 hour to make sure the limbs are balanced- symmetrical. If one imb is weaker (the distance from the strings increases), press the string down into it and hold untill balanced. Then, once the bow is cooled, and if the limbs do not twist, try to test-shoot it at lower draw lenght. It is better now to hold the grip loosely to avoid torque.
If the limbs twist, then un-string and corect the twist by warming the limbs while un-strung. This warming should be at a little higher temperature and maybe a little longer than before. Then cool-off and repeat stringing etc as above.
I hope it works for you. Patience is essential in these operations. I also suggest to employ a friend to attach the string while you bend the bow. It is very easy when working alone to cause twist and over-stress the limbs. Full control during stringing is very important. You may want to make the pegboard for this.
Adam
Measure your RH in the room: if it is around 40 to 60%, the limbs will always be floppy as they are and there is no use to fight it. You want to shoot the bow in normal conditions like that outside anyway and the bow was made for these conditions. If above 65%, then maybe wait a couple of weeks for the room to dry-out as the heating season progresses.
I keep my bows at no less than 30%RH and use a humidifier in the winter if needed.
As to tillering:
There is no need to obsess about the shape of the limbs at the grip now. I suggest to warm the siyahs (only the siyahs) when the bow is un-strung, then string it and see if the siyahs are straighter and the bow is symmetrical. Wrap the limbs with something to hold them in this position (as Koreans do) and wait for a couple of hours to cool, checking every 1/2 hour to make sure the limbs are balanced- symmetrical. If one imb is weaker (the distance from the strings increases), press the string down into it and hold untill balanced. Then, once the bow is cooled, and if the limbs do not twist, try to test-shoot it at lower draw lenght. It is better now to hold the grip loosely to avoid torque.
If the limbs twist, then un-string and corect the twist by warming the limbs while un-strung. This warming should be at a little higher temperature and maybe a little longer than before. Then cool-off and repeat stringing etc as above.
I hope it works for you. Patience is essential in these operations. I also suggest to employ a friend to attach the string while you bend the bow. It is very easy when working alone to cause twist and over-stress the limbs. Full control during stringing is very important. You may want to make the pegboard for this.
Adam
Thank you, Adam.
Very detailing and precise advice. I have and use all tools what i see in koreans hands. I string bow vith "dojigae"- tepliks- its easy. I made wood vice like koreans and chinese masters use in all bow work. Now i try somtime string the bow vithout dojigae , only vith hand and foots , but always is neer me mi friend- if i need help. I was working very similar like you advice me besides warming the horn side in unstrung bow. Ok. I will try this.
Very detailing and precise advice. I have and use all tools what i see in koreans hands. I string bow vith "dojigae"- tepliks- its easy. I made wood vice like koreans and chinese masters use in all bow work. Now i try somtime string the bow vithout dojigae , only vith hand and foots , but always is neer me mi friend- if i need help. I was working very similar like you advice me besides warming the horn side in unstrung bow. Ok. I will try this.
First tillering
Korean method of stringing a bow
Yes Jack,
i build somthing like this in first picture long time ago. And visible like korean master modelite side of arm and kasan . But i prefer in this only hand and foot . Bow loks like very thiny and fragile thing... I think that our discussion is very beneficial for all who have , building or buy composite bow. Vithout this knowledge and experiences man can destroy , or dont corect use this phantastic weapon.When i looking in posts i find korean archer- Soso who wrote about his first experiences vith composite bow. I contact him . Maybe he told us more .
i build somthing like this in first picture long time ago. And visible like korean master modelite side of arm and kasan . But i prefer in this only hand and foot . Bow loks like very thiny and fragile thing... I think that our discussion is very beneficial for all who have , building or buy composite bow. Vithout this knowledge and experiences man can destroy , or dont corect use this phantastic weapon.When i looking in posts i find korean archer- Soso who wrote about his first experiences vith composite bow. I contact him . Maybe he told us more .
I found this in You tube.
http://www.youtube.com/watch?v=tOPIaOPLdHU
http://www.youtube.com/watch?v=tOPIaOPLdHU
I find that straightening the upper limb is a matter of taste. Flattening the grip section by setting the bend would stablize the bow somewhat but flattening the limb does not seem to change the points of leverage.
A master can do what a student should not. Take note. -j-
A master can do what a student should not. Take note. -j-
The humidity should not change quickly for not tillered bow. Specially, if the humidity decreases suddenly in winter, backing show tedency seperate. I lost one of my bow's backing for this reason. In very cold - low humidity, sometimes I use wet sponge to moisten the bow.
Cem
Cem
Thank you Cem , but i dont leave mi bows in cold rooms. I have mi bows vith mi new Korean"friend" in 50-60 % humidity and 25-26 ?C and he "playing games" like crazy horse every time vhen i try string him. Only when i good heat him , he quied . Now i have him in box near heating vith stabil 35-40 % - 26-27 ?C.Its better.
Yes, it is better keep the bow in unchange temp room is the best.Old Turkish bowyers used upstairs room of the old style bread oven. İn add. keep the unfinishing(drying period) bow is more important .
Cem
Cem