branch bow top or bottom?

[willie]

In a neighboring thread, there were two opinions offered about whether the top side or bottom side of a juniper limb was used for making a bow. I think I have read about both. As I was just about to take two conifer branches to the band saw, I thought I would ask what others thought.

Experiences?    Articles read?   Links?    Pros and cons? 

[Pat B]

I think I've heard that with conifers you use one side and with hardwood you use the other. The trouble is I can't remember which is which. 

[Mo_coon-catcher]

I gathered a bunch of cedar branches last fall to mess with. I think it’s the top you use on conifers but I’m not positive. These by far have much tighter rings on the top and the top sides are completely clean of branches where as the bottom is full of them. So I’m leaning towards top on conifer.

Kyle

[PatM]

 It's "supposed" to be the top of hardwood and the bottom of  conifers.

https://en.wikipedia.org/wiki/Reaction_wood

[Morgan]

I always heard top of branch for the back of the bow because the top is grown under tension. Also read that the stave will dry into reflex if reduced before drying. No personal experience though.

[Hawkdancer]

Only got Comstock's and TBB to refer to, but I'm sure they show the cuts on conifer limbs being on the top side.  Never cut one myself.
Hawkdancer

[willie]

It's "supposed" to be the top of hardwood and the bottom of  conifers.

https://en.wikipedia.org/wiki/Reaction_wood

Pat, I am glad you put supposed in quotes. Here are some thoughts about trying to use conifer reaction wood.  Selecting the better part of the branch may not be as straight foreward for a conifer, as It might be for a hardwood. In a hardwood, the top of the branch is rich in cellulose (good for tension), and the branch has a natural crown (good for a bow that can benefit from a lighter or trapped back). It just makes sense to leave the back alone and let the belly fall wherevever in the limb that it ends up at.

Conifers on the other hand, put their reaction wood on the belly, by forming wider  lignin rich rings. I have found that this can make a belly that can be bent further than normal. but in order to utilize the belly as such, the limb has to be tillered/decrowned on the back. My limbs are about 2.25 inches in diameter, and this decrowning  leaves almost all of the back below the center pith--- in compression wood also. Maybe not such a good idea.

The wood in the upper side of a conifer is said to have no special qualities, but at least it is not compression wood. I need to have a bit of diameter in my stave to get the width I need, so my thought was to take the limb out of the center of the stave, both decrowning the back, then tillering normally on the belly.

Hawk has mentioned the top side usage, on what I assume may have been for a juniper/sinew composite? Maybe the juniper was selected for it's compression qualities? from the top none the less? being sinewed, maybe the tension qualities were of concern?

Knowing of precedents might help.

[Msturm]

Hey there Willie!

What conifer species are you experimenting with? 

[DC]

I've been eyeing the big Spruce in the backyard with the same thing in mind. I was thinking I would saw one right down the middle, somewhere below the pith and back it with Hard Maple. I'm thinking that the real hard compression wood will be closer to the outside of the limb. As the branch gets bigger and heavier it makes more compression wood? No sense tillering off all the good stuff. Just guessing though

[willie]

Mike
Spruce primarily, although I have a couple of pieces of hemlock from up in the pass. The hemlock felt real rubbery when I cut them, guess I will have to see what I think about them when it dries.

Don

If you were to back with some maple, you would be making something like the two wood composite of the old world arctic tradition  The "better" back would be able to take advantage of any increased benefits from a more elastic compression wood belly.

My concern  is somewhat the opposite. A conifer self bow may need to be designed around the best back I can get from the wood, both design wise and materiel wise.

[Springbuck]

   "It's "supposed" to be the top of hardwood and the bottom of conifers."

  This is how I heard it, and I think that for QUALITIES of the wood this is true, like for density, elasticity and such. 

But, like Jim Davis said recently in another thread, sometimes it's about using the best stave even if the wood is merely decent.  I often take two bows from say, the upside and downside of a leaning elm sapling and the wood is different, but not that much different.  The up side will dry into more reflex, but the bottom will be more dense and harder, making a narrower bow or the like.

  I have never used conifer compression wood, but I've been tempted.  It seems obviously more dense and strong.  I didn't understand everything Willie was saying about the back and belly, though.  Taking a stave from the upside of a juniper branch to me comes down to the fact that long shaded up side will have no branches or knots for decades, while the underside often has tons of greenery hanging down.