Jkekoni's Horn bow project

jkekoni · Post by **jkekoni** » Fri Nov 22, 2013 12:57 pm

Horn bow core.

136cm along outer curve
35cm net reflex, measured from belly side to tips.
9cm splice.
3 piece
34mm wide limbs.

Horns are 44cm from start of splice, and semibending area is last 10cm. This gives around 25cm bending area.

Handle is made from unknown hardwood and limbs are commercial mapple boiled to curve.

Horn have been grooved with 3mm raster and slightly over 1mm deep, less in the end. Not matching. Glued with casco 24h professional strong epoxy as is the core. Glue line is good.

(My last attempt was hide glue and unsuccesfully matching grooving...)

I try to get 60#-65# @29", which I know to be underbuild.
(I think 3x that is obtainable from this size of bow.)

Horns are factory straightned and glued to perry reflex.

Any good ideas for limb thickness without sinew? (now 13mm)

Ottoman t?rkish bows has a formula, but I think all calculations have been done with bows with sinew.

http://perinnejousi.utbl.net/keskustelu ... _1_168.jpg

mikekeswick · Post by **mikekeswick** » Sat Nov 23, 2013 8:21 am

Why did you bother making grooves when you are using an epoxy? No need to worry about grooving just flat surfaces roughened would have done the job.
It risky using epoxy because you won't be able to use heat to correct twist etc. fingers crossed it's plumb straight!

jkekoni · Post by **jkekoni** » Sat Nov 23, 2013 10:39 am

I did grooving to avoid failure of wood just near the glue line.

My idea is that grooving makes the MOE (bendiness) not to change instantly, but gradually, the same as with proper glue.

(Proper glue has moe simiilar to horn, so the moe changes once not twice, anyhow the idea is same.)

I do not claim grooving makes more durable core with epoxy, I just described my reasoning why it may...

Arry · Post by **Arry** » Sat Nov 23, 2013 11:40 am

mikekeswick wrote:It risky using epoxy because you won't be able to use heat to correct twist etc.

This would be a very good reason indeed to stick to natural glue. But are you sure? I am asking because after all, the horn stays thermoplastic - whether it was glued using epoxy or hide glue.

Tc · Post by Tc » Sat Nov 23, 2013 1:46 pm

If you go for a 60#-65# bow the limb should not be more than 8-9 mm at the thinnest part of the limb (without sinew). Epoxy is useful stuff but not for hornbows. I did the same at my first (failed) bows but never more (I was not able to reuse the horn..) Good luck!

Pat Menzies · Post by **Pat Menzies** » Sat Nov 23, 2013 5:20 pm

Many Epoxies can be adjusted with heat. The original article in Primitive Archer on constructing a horn bow involved the use of Epoxy and that guy made a lot of fine bows.

mikekeswick · Post by **mikekeswick** » Sun Nov 24, 2013 8:06 am

Pat Menzies wrote:Many Epoxies can be adjusted with heat. The original article in Primitive Archer on constructing a horn bow involved the use of Epoxy and that guy made a lot of fine bows.

Like which ones?
All the ''epoxies'' i've used aren't good over 55 deg celcius. The point I was making is that hide/sinew/fish glues are fine with the temperatures needed to correct a hornbow but from what I have seen most modern epoxies won't handle the sort of temps needed for corrections without having to worry about them. Resourcinol has a high resistance to heat once cured and wood glued with it can be steamed.
I think most moderns glues works best with good mating surfaces and little in the way of gaps. Epoxies tend to have excellent wetting properties so grooving, roughening up etc isn't necessary and make weaken the joint.
Anyway the way to know for 100% the working properties of the specific glue you are using is always, always refer to the tech sheet. I always get this data from the manufacturer before using a new unfamiliar glue.

Pat Menzies · Post by **Pat Menzies** » Sun Nov 24, 2013 5:06 pm

G flex and the toughened variety of G Flex don't mind the same sort of adjusting as Hide glue. Keep in mind that some twists can be temporarily corrected through each shooting session, even if they creep back over a long period of unstringing.
I've never seen a tech sheet on animal glue.

robinhoodfromhun · Post by **robinhoodfromhun** » Sun Nov 24, 2013 7:56 pm

Don't worry about epoxy! You can correct the twist (if it needs) if you will use organic glue for sinewing. I have corrected a huge twist at my first bow. I used epoxi for the horn and mix of fish bladder and hide glue for the sinewing.
I don't use epoxi anymore, but only because I want to use original (organic) materials for horn bows.

jkekoni · Post by **jkekoni** » Mon Nov 25, 2013 9:33 am

I do remember reading (from here) that epoxied bow can be corrected with heat. I know it is not mentioned in Ottaman T?rkish bows, because the conversation is newer that the book.

resorcinol

http://en.wikipedia.org/wiki/Resorcinol_glue

I do not see the point of replacing natural glue with a fake one with no good gap filling properties... or actually if it is likely to have longer open time.

I do not think bow building is for people who are worried about failing.

Horn bows less so, because they have much more time invested ... and money too.

I will use Dick hide glue for the sinew. I have used it and I have it. I plan to use moose sinew and red deer sinew, if I for some reason fail to get it.

mikekeswick · Post by **mikekeswick** » Tue Nov 26, 2013 8:27 am

I certainly wouldn't be using wikipedia for info on glues...

I got my information on resourcinol from the people who make it now. The guy I spoke to knew just about everything possible about it

So do you think that hide glue has good 'gap filing' properties? May I suggest otherwise...lots and lots of tests have been done on collogen glues.
I will stand by my statement that resourcinol would be a good choice if for some reason you didn't want to use a collogen glue that has been proven to work perfectly.
Just don't roughen the horn/core surfaces and definately don't groove.
I have made quite a few minature horn bows with this glue and know that it does work. I used a modern glue simply to speed up the process of making these miniture bows.
Jkekoni - resourcinol comes in 3 versions with different open times. This is on the spec sheet.
What do you need gap filing properties if there are no gaps.....just prepare flat surfaces??
Do I strike you as someone who is worried about failing??? Do you want to see my pile of experimental bows....

It's a big pile!

jkekoni · Post by **jkekoni** » Tue Nov 26, 2013 12:52 pm

mikekeswick wrote:I certainly wouldn't be using wikipedia for info on glues...

I agree... I just googled and found very little information of generic nature...

So do you think that hide glue has good 'gap filing' properties? May I suggest otherwise...

I did not say so, nor did I mean to imply so. My point was not to replace period material with non period material without benefits. Hide glue is not a good gap filler -> replace with epoxy as fake material with gap filling properties. Even so as I said if resourcinol has longer open time it is alone a reason to use it.

I will stand by my statement that resourcinol would be a good choice if for some reason you didn't want to use a collogen glue that has been proven to work perfectly.

I am not qualified to comment on this one. I have newer seen or used resourcinol as you probably guessed already. I know collagen glue is known to work for period bows. It makes it good enough, not perfect...

What do you need gap filing properties if there are no gaps.....just prepare flat surfaces??

Poorly mating surfaces.... epoxy is for good for the lazy ... ( not meant to point anyone ... except perhaps myself)

robinhoodfromhun wrote: Don't worry about epoxy!
jkekoni wrote: I do not think bow building is for people who are worried about failing...
mikekeswick wrote: Do I strike you as someone who is worried about failing???

Should we leave the conversation about conversation and rather have a conversation about bow building...

robinhoodfromhun · Post by **robinhoodfromhun** » Tue Nov 26, 2013 1:50 pm

How did you bend such a thick wood? Did you steam it, or cook it? I wondering if I could bend a wood for Hungarian bow's ears. I should be able to bend a 25 mm thick lath for that

fusizoli · Post by **fusizoli** » Tue Nov 26, 2013 3:28 pm

That made on Avar bows.

jkekoni · Post by **jkekoni** » Wed Nov 27, 2013 7:58 am

How did you bend such a thick wood?

I am using commercial maple, with unknown subspicies.
Hazel <Corylus Avellana> works too, but must not be green, but has to be dried before immersion (original research).

I rounded corners in the inner curve.
I immersed into water for 4 days. (Ottoman turkish bows recommends 3 weeks for kiln dried wood, I do not.)
I exchanged to hot water from tap.
I headed to boiling point.
I boiled for 70-90 minutes.

I bent to form and clamped with C-clamps. Kept there for over a week or so. Maple and 18-20mm dry thickness. Thicker wood than this has been bent to tighter curve. Metal strap helps against splits, but i did not use any since they are in the way, there is hurry with bending.

Steaming has newer worked for me.

Jkekoni's Horn bow project

Jkekoni's Horn bow project

Re: Limb thickness without sinew? ( an asiatic hornbow proje