compression wood laminated bows

[stuckinthemud]

Afternoon everyone!

I have been searching for bows using siyahs and stumbled across a link on PA to a thread on Paleoplanet about Finno-Ugric two-wood laminated bows ( http://paleoplanet69529.yuku.com/topic/29305/North-Eurasian-laminated-bow  huge long thread and really fascinating with lots of useful information, highly recommended).  These bows normally use compression pine and birch but sometimes use other woods including choke cherry. I may have missed something in the 15 page long thread and it could be the cherry is for the siyahs?  Anyway, it set me thinking - I have compression yew and choke cherry in my wood-pile, so has anyone any experience of using compression wood in a laminate, anyone built a Finno-Ugric/North Eurasian type bow? They seem to pack a big punch without using horn or sinew. 

[PatM]

Yes, the cherry is for the tips.  You can use anything really though. I think a few guys here have dabbled with compression wood but the general bow design is just a perry reflex with added tips. You can make the same basic design with a wide variety of materials and end up with this style of bow. Those materials just happened to be the best that they had available.

[stuckinthemud]

Thanks Pat, Perry reflex is glued-in reflex?  The shape on those bows is really nice though.  Kinda like the idea of a bow that gets faster in damp conditions - it rains a lot in Wales    What do you make of the way they nock the string right on the end of the siyah - never come across that before.

[maatus]

I guess you mean bird cherry (Prunus padus)?

Sometimes also willow was used for backing but mainly birch.

I've made one bow out of comp. spruce (Picea abies) with birch backing. It was OK, but not that good what pine is, being very fragile and stiff, also likes to crack if dried too much

Is your yew piece going back and forth when humidity changes?

[stuckinthemud]

Haven't looked at it that closely, only cut it last spring, so its stickered up to season but its the underside of a large branch but should be OK

[PatM]

You could just use Ipe as a belly.  It is actually strongest at a slightly higher moisture content.

[stuckinthemud]

Ipe doesn't seem to be that easy to come by over in the UK - decking boards off that auction site is about the best I can find

Just guessing but I imagine the sub-arctic bows didn't use silver birch - I'm literally surrounded by the stuff (the woods up and down the valley I live in are, mostly, mixed silver birch, hazel and beech) but I understand silver birch is not a good bow-wood?

[PatM]

I wouldn't know. dragonman is in Wales and he has posted plenty of Ipe bows. I bet it's more readily available than compression conifer wood of any quality.

[stuckinthemud]

Maybe I 'll PM him ask him where he gets it from

[loon]

Kviljo is good at this stuff. Apparently compression pine approaches yew in compression properties, if not even better from tetratzolover's videos O_o. I'm surprised no Native Americans used it as far as I know, maybe certain species of pine in Europe are better. such as pinus silvestris or whatever. They did use incense cedar though, I wonder if they used the compression side

perry reflex... with two laminations? wat

[maatus]

Of course you could use any compression strong wood as a belly. But the point of doing compression wooden bows is, that they perform better than any other wood when it comes to high humidity.

What I've read and heard of perry-reflexing, the belly piece needs to be forced to reflex and then glued to back piece, otherwise the "effect" won't happen. Compression wood staves are usually already reflexed so...

First pic is the bow being as dry as it could be at home.

Second pic is after moistening it for one hour or so.

[willie]

Stuck,
Nice to see someone exploring the possibilities of compression wood. Looking forward to whatever you wish to pass along.

Markus
have you found any advantages to using compression wood other than it's moisture tolerance? The bows I have made from spruce compressionwood seem better for heavy arrows, Not very fast otherwise.

willie

[PatM]

  I guess it depends if you do the glue up with the belly piece wet or dry.
  The increased moisture content of the damp belly will add mass so it's hard to say how much better the combination would work over a simple Perry glue-up.

  Has anyone actually tested these bows are prove they are better than any other at high humidity?
   
 I remember Kviljo mentioning that a bamboo Ipe bow he glued up with minimal or even no reflex seemed to increase in reflex when he had it out unsealed at a rainy flight shoot.

[Frodolf]

Yes, Kviljo is the guy to ask. In fact, I happen to know that he is currently, as in right now, giving a course teaching people how to make these bows.

I've given them a try a few times (and I've read the PP thread from cover to cover). I've had some bad luck making these bows but it's my ambition to learn how to make them and do it well. In fact, yesterday I started making one – my forth (or is it fifth?) go. Maybe I'll post some pictures eventually. I'm using compression spruce and birch. I've tried both spruce and pine in the past and I couldn't detect any significant differences in properties or qualities, they seem to be pretty similar. I think the most important thing is the quality of the piece of wood – the darker it is, the stronger in compression. That's my working hypothesis anyway.

PatM, judging from the pics, the increase in reflex is something like 3" or so. That's a lot. The bow would have had to suck up a whole lot of moisture for that the increase in mass and increased reflex to cancel each other out. Don't you think? I also think the effect may happen with other combos of woods, like you mention, but if it was as pronounced as with compression wood I think it'd be common knowledge.

OP: I think compression yew will work nicely. Fine wood for a belly!

[PatM]

I meant wet reflexed wood versus just gluing in that amount of reflex with another belly wood for comparison.
 
  I'm thinking more of someone pursuing the design if not the exact materials.
 
 People have the dry wood(often even over-dried) concept drilled into them so the idea that a slightly damp combination might have any increased potential is going to be a tough concept to adapt to.