I know, I know... heresy! :evil: :evil: :evil: (how could you! You right b@#%rd! etc etc...) yes, yes... hold those thoughts...
I simply wanted to ask as someone who is just beginning to teach himself the art of bow making if this would be a reasonable thing to do for the first bows I make.
I've been wondering about it in terms of making resin and fibre forms to imitate horn. I know, not traditional. Horn is not easy to get in Canada in the right form. There are many import restrictions on horn and other animal products here.
Even the sinew is a real problem to secure a supply for, again because of the agricultural product import restrictions.
So, I thought as a way to learn that a few modern materials created to imitate the originals could potentially serve well enough.
I'm not a fan of fibreglass, it's a right devil to work with. Horn is smelly stuff at best, resin is not a lot better. Then there's the issue of creating a resin/fibreglass form to imitate the shape, dimensions and curvature of horn... now that I think of it, this may be more work than it's worth... (sorry, thinking as I write this)
Anyhow, to a budding novice and new student of the art, I thought I'd ask opinions and advice.
Please keep the flames and darts to a bare minimum. (they'll largely be ignored anyhow) :lol:
ginni
You can combine fiberglass and phenolic on the belly, like korean bowmakers. You can then tiller the bow by scraping the belly, exactly like a hornbow and it will looks like a hornbow.
Eppo Wolgen
Byron,it really is not that hard to get horn in Canada.I have ordered horn several times from Peter Cua from the philipines.Not a problem.
As for sinew,you need to do some legwork or let your fingers do the walking and find a butcher shop that processes moose and deer and get a bunch of legs.Fall is coming and the hunters will get the animals for you.Take it from a fellow ontarian.
Byron
I hadn't thought of the deer/moose source before. There are a few places that process game. I'll make a few calls on that.
I'm really not sure that there's anything that can truly replace sinew on a bow. I"m all for trying a few times, but in the end the bow really cries out to be made of the natural materials.
I think I'll experiment with phenolic and fibreglass on a few while I work on re-building my workshop over the next few years... it's a disaster and needs to be torn down and replaced. Thankfully I have a large back garden!
Anyhow, I don't think my wife wants me preparing horn in the basement... ;)
I carve thumbrings from horn and antler and I wait until the weather is good and carve outside... far, far too smelly and dusty for indoors. (always wear a dustmask/respirator when working with horn, bone and antler, the stuff is murder on the lungs!)
Thanks for the pointers on moose etc!
Byron
Stephen Selby
Ok. The text of your post is clearer than the title.
You ask if you could use a man-made material to perform the extension-resisting function of the sinew and a similar material to perform the compression-accepting function of the horn.
I think the answer is 'yes'; but you would have gone to more trouble and added more weight of materials than if you just went ahead and made a fiberglass bow in the ordinary way.
S
jkekoni
Fiberglass and horn work in fundamentally different way.
Fiberglass is very stiff (compared to wood). (High MOE)
It however is not very flexible. limbs made from FG can be made thin,
thus allowing them to bend.
Horn is low stiffness (compared to wood) and highly flexible, especially in compression.
Sinew/glue composite work in tession only. It also has even lower stiffness than horn, but will bent almoust unlimited amount.
Byron
I think I've got it down to looking only for a synthetic replacement for horn and from what I can tell, phenolic might work. Now, that being said I started to do some research on phenolic and you wouldn't believe the varieties and compositions of materials that are available, not to mention colours!
There are phenolics for flexibility, internal heat and stress dissipation, high friction, heat etc etc... there's paper substrates, linen, cotton, different resins and on and on... this material isn't simple!
Anyhow, so far the idea is to narrow down one or two variations on phenolic whose characteristics are based on flexibility and retaining shape and elasticity.
Sinew, no plans to replace that. Sinew is sinew, at least for now... who knows, once I re-build my garden workshop I can work with the smelly stuff without fear of being made to sleep on the sofa.
I'm still only fiddling with possibilities at this juncture. I'm leaning towards birch as the core, only because it's plentiful here and a nice wood to work with.
It's going to be some time before I have the space I need to work in, but if I make any progress I'll post images.
;)
Stephen Selby
...and the glue.
I think when we focus on horn/sinew bows, it's easy to overlook that the horn was the only part that was not thoroughly permeated by glue. The properties of glue must have a very significant effect on the performance or weight (in hand) of different bows.
Uli
I have also tried fibreglass backing for replacement of sinew and it works but not as nice as sinew. Preparation is smelly and toxic and you ruin your tools with the fibreglass glue.
If you really want to find modern materials as a best replacement for horn and sinew, you will not save time or money I think, as this is also complicated enough and you have to invent it yourself.
my guess is to use traditional material, its also much more fun to work with.
:-)
jkekoni
I have done some experiments with sinew-wood-phenolic (HP2061) and they have been failures.
I however think that one of them was pure belly failure.
And the other was glueup problem.
( They may also be due to the expoxy glue not suitable for the use, or that the somewhat thin (3mm) phenolic places neutral axcel on glue line. )
I have been thinking that I could convert the bow-attempts to bamboo belly.
I should document these as I have taken ton of pictures. They could be helpful for others to learn about my mistakes.
Justin Ma
I heard from Peter Dekker that Koreans have developed a simulated horn and sinew material. However I don't know what that material is called.
Patrick Menzies
I think the tendency is to try to find a horn substitute when there really isn't one. It's better to just practice the construction of the composite bow going by the process of using three layers. Just use a maple core and use the best compression wood you can get for the belly. It will work just as well unless you are trying to build an extremely short, long draw bow.
You can find several examples of bows made without horn and typical composite construction that are very fine performers.
PS I also live in toronto. We should get together some time to talk bows.
Byron
You know, the idea of using a good compression capable wood in place of horn is a pretty good idea! Thanks! Lots of room to experiment too.
Yew, or at least the heartwood takes compression very well. Tempered bamboo too. There are certainly options. I wouldn't be building an extremely short limbed, long draw bow anyhow, so this could make life much easier.
As for getting together, that sounds a plan. I work in the downtown area most days of the week. Beer and bow making.
b/.
jkekoni
No wood compresses even near to the same range as horn.
I think bamboo is the best substitute belly, however this poses extra problems since you cannot scrape the belly of the bow, since the power fibres are in the belly.
I have been thinking of bamboo floorings tough, they would allow belly scaping, but naturally would not be even near as good...
Daniel T.
Instead of investing time in experimenting on resin composites with unknown outcome, I would rather use it to get the workshop in shape.
Or, if the basement has a window, you'll be fine. Just get a fan. If you work the horn on a belt sander with a very rough paper the smell is not much of a problem.
Alex S.
The elasticity of horn make it superior. Fiber glass is too stiff material, even though it has much compression strength, that is why I think Lukas make new material usage in his hybrid model. He uses more elastic material, maybe sacrifice some compression strength.
I wonder, maybe it is not good idea to heat treat for more compression strength if material can already be capable of taking strain without fail. Bamboo can do this, though it takes set. Heat treating bamboo will cause it to become too stiff to bend sharply I think. So maybe for longer design bows heat treat is benefit but shorter bend radius bow should have un treated belly.
What do you think?
jkekoni
Patrick Menzies wrote:
I think the tendency is to try to find a horn substitute when there really isn't one.
I think this is due to horn is
a) hard to get
b) expensive
c) hard to process
Byron
Yes, usable horn is hard to get, expensive and indeed, very hard to process and doubly so when you don't have the workshop/space to boot.
I was thinking of using bamboo for the belly on my first bow or two and using sinew on the back. I can't see or at least, I've not found a synthetic that is anything like sinew, so I'm just going to stick with it.
Horn on the other hand, well... I'd love to and some day I will... but my initial attempts will likely be birch/bamboo/sinew.
glass/resin has the compression, but not the same properties as horn, it's a non-linear / micro-crystalline material, so the flexing properties aren't ever going to be the same. If perchance I happen on the ideal synthetic that hints at promise I may try it. At the same time, if I happened to come into possession of the right horn, I'd suck up the small and difficulty and try that too...
Right now I'm making primitive selfbows at youth weights, mostly for my daughter. I've broken about 40% of what I've made and every breakage is a learning experience. Next up is a red oak version of a Meare Heath bow... with sinew wrappings.
I've recently found a small sawmill operation where they already process and save ash, oak, maple, birch, juniper, hemlock etc. for a few other local bow makers. (I'm not calling myself a bowyer, that's for others to decide and when what I've learned and can make merits that title)
So, all in all, the materials are coming in, save for sinew and horn...
b/.
Tapio Manner
At the moment there no synthetics that can even passably replace sinew/horn. That is because the elastic properties are too far apart, main problem being usable strain that are larger in natural materials. That makes in impossible to copy the geometry in synthetics, the limbs tend to become unusably thin.
TLM
Justin Ma
Justin Ma wrote:
I heard from Peter Dekker that Koreans have developed a simulated horn and sinew material. However I don't know what that material is called.
Okay, I found some brief references to a material called "black paper pulp" that is used to construct the belly on laminated (Hwarang) Korean bows.
i am in a different case from u all.a slaughterhouse is near to me ,thus,sinew and baffallo horns are easy to get. piles of them!!!!....
i have tried more than 15 hornbows in the last 4years.most bows had the horn broke from bamboo.the problem lies in the cheep bladders that i use---maybe.
days ago i try some all-bamboo-laminations,and epoxy works better than fish glue. do u think it practical to try epoxy in gluing horn and bamboo?
i mean ---still to make a hornbow with traditonal materials and in traditional way .
ginni
This mysterious black paper pulp is actually phenolic. Under this 1 mm phenolic layer is black fiberglass.
I strongly believe that koreans use this phenolic because it looks like horn but also because it is good in compression and can be tillered like horn, by scraping and sanding.
Master Park have now a new model with natural horn on the belly. A dealer says this have 40% of the feeling of the real hornbow. I dont know if this have fiberglass under horn.
With rounded back covered with birch bark, black horn belly, it looks very close to real hornbow.
WarBow
Ginni, how I contact the dealer?
Doesn't Grozer have something similar and name it bio composite? Real horn and sinew is used in bio composite but the glue is not fish bladder apparently.
ginni wrote:
This mysterious black paper pulp is actually phenolic. Under this 1 mm phenolic layer is black fiberglass.
I strongly believe that koreans use this phenolic because it looks like horn but also because it is good in compression and can be tillered like horn, by scraping and sanding.
Master Park have now a new model with natural horn on the belly. A dealer says this have 40% of the feeling of the real hornbow. I dont know if this have fiberglass under horn.
With rounded back covered with birch bark, black horn belly, it looks very close to real hornbow.
Tapio Manner
Phenolic resin has the lowest breaking strain of the commonly used resins. Just plain bad choice, it is no substitute for horn.
TLM
ginni
Tapio Manner wrote:
Phenolic resin has the lowest breaking strain of the commonly used resins. Just plain bad choice, it is no substitute for horn.
TLM
It seems to work, at least for koreans. :D
Warbow, You have a PM.
Tapio Manner
It seems to work, at least for koreans. Very Happy
It works but - epoxy is stronger and can be coloured whatever one wants and it has larger strain. The main reason for phenolic seams to be that at one time it was cheapest...
Presently phenolic resin is used only in some fire critical applications.
TLM
ginni
As I know, the best pool balls are made from phenolic -Aramith balls.
I worked with the material making few rings and is superior, is elastic and more resistant than polyester balls.
It seems to have good compression properties.
Dusan
I think that here is no discusion about phenolic superiority. Lukas Novotnys new bow generation show how good is this material. Phenolic back and belly, wood in midle - vith no polyester .
Tapio Manner
If phenolic resin was that good aircraft would be made out of it, now they are practically all made out of epoxy. Some military AC have fancier stuff like bismaleimides or cyanate-esters.
Standard polyester is good for boats but not much else.
You do not have to believe me (I only do it professionally), look up the numbers yourself!
TLM
jack farrell
I have been very successful making Asian style bows with bamboo BACKS over juniper, walnut, teak, oak and many other woods. This can be tillered on the edges and belly after glue up. There is a large initial loss of reflex which then stabilizes. NO BAMBOO ON THE BELLY.
Original bows were assembled with white carpentry glue and the two oldest have been used for over 20 years. These are light target bows with good range.
The Korean synthetic bow that WTAF gave to me is an excellent shooter. I gave it to a friend because I prefer natural materials.
Alex S.
Tapio,
I think maybe the phenolic is consider inferior material over other high tech plastics because of its relatively low modulus of elasticity, causing it to not provide much strength in stiffness. Though, this would be the biggest advantage in bow making if the material is able to not deform under the stress. That is why before they use to use spruce wood for aircraft construction, because it has highest stiffness to weight ratio at the time.
This is why its difficult to find a wood that can work as horn replacement, because most wood that can withstand the compression stress is too stiff to be made into composite bow shape. Bamboo is probably closest "wood" (that I have used) that has this quality.
Tapio Manner
I think maybe the phenolic is consider inferior material over other high tech plastics because of its relatively low modulus of elasticity
Its MoE is only slightly lower than the other resins, the main problem is its strain to failure that is just low. In other words it is kind of brittle.
All fiber reinforced composites take most of their strength and stiffness from the fibers, the resin is their to glue the fibers together, transverse properties take exception from this rule but they are not that important in limb bending. (there are cases when transverse "Poissons" strain causes longitudinal splitting)
At the moment no synthetic material can act as direct replacement for horn or sinew.
That does not mean that bows having the approximate shape cannot be built, it just requires play with limb thickness and width, meaning a good bowyer who knows the materials he is using at the moment.
TLM
Dusan
Tapio Manner wrote:
At the moment no synthetic material can act as direct replacement for horn or sinew.
MOE 9Gpa
Compressive strength perpendicular to laminations 300 Mpa.
This is 300/9000=3.3% an is not in my books low.
It is off course low if compared with real horn.
(MOR/MOE is typically 0.6-0.9% for most hardwoods 1.2 for yew.)
Tapio Manner
A good horn has a strain to failure of about 5-6 % in compression and sinew has 7-8 % in tension.
On the phenolic paper laminate the transverse value is unusable because in a bow very little through-the-thickness strain exists. The plane value of 150 MPa has to be used. So it does not look so good.
With glass fiber about 2.5 % is possible and with carbon 2 % (both tensile).
When one has to make a bow with bendy limbs horn /sinew is a very good pair of materials to use. Also when energy storage is required, large strains are very useful, rubber is a wonderful material to store energy for short periods.
TLM
jkekoni
You mean:
It does not help that it can take a lot of compression, since it will delaminate between layers much before that.
Tapio Manner
It does not help that it can take a lot of compression, since it will delaminate between layers much before that.
I guess I expressed myself a bit unclearly, the higher value is in the thickness direction, the lower value is the in-plane value that must be used if the laminate is put under compression in the belly.
Delamination is a problem with phenolics as the resin is brittle in comparison and its adhesive properties are not really very good. For example it needs more pressure than other adhesives when wood is being glued, thats because it does not wet the surfaces well, it has to be pushed into the surface structure.
TLM
daryush
jack farrell wrote:
I have been very successful making Asian style bows with bamboo BACKS over juniper, walnut, teak, oak and many other woods. This can be tillered on the edges and belly after glue up. There is a large initial loss of reflex which then stabilizes. NO BAMBOO ON THE BELLY.
Original bows were assembled with white carpentry glue and the two oldest have been used for over 20 years. These are light target bows with good range.
The Korean synthetic bow that WTAF gave to me is an excellent shooter. I gave it to a friend because I prefer natural materials.
Jack, could you share some photos of your bamboo/wood Asian bows please? :D
