Primitive Archer
Main Discussion Area => Bows => Topic started by: DavidV on March 23, 2016, 12:50:22 pm
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The local hardwood dealer had a load of what was labelled "russian birch" last time I went in. I can't find much on it and all searches pull up baltic birch plywood. Most of it's really clean and straight grained and it weighs just a little less than hard maple. It's hard to find straight grained boards there so does anyone think it would be worth trying?
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Trees don't recognize national boundaries. ;) It's the same tree.
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If it's silver birch -- one possibility -- I would sure try it, since that wood appears to have reasonably good properties for a wide limb style whitewood bow. And because I've built several successful black birch bows before, I'd be curious to see how it worked out.
I'd personally start out making the limbs 2" wide minimum at the fades, and double the draw length plus 10" for bow ntn and see how that went. That might be conservative. Up to you, of course!
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That sounds reasonable B
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Pat, i guess the follow up question would be which birch it actually is... Since they kind of vary in properties.
PlanB, good to hear you've had luck with birch, Silver seems to be on the higher end of the species.
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Most of the Russian birch will likely belong to either of three species: silver birch, downy birch and white birch (Betula platyphylla).
Stiff wood for its mass, should make good bow wood if you find straight boards.
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Looks like silver is a little stiffer than sugar maple and downy is a little less stiff. Both birches are about the same SG. I don't know about the white -- different species than the white here.
If you got a sample of the birch and some hard maple, a comparative bend test of a strip about 1/4" x 1/2" in section might help you decide how wide you want to make it regardless of exact species. I'd feel comfortable w/ 2" if stiffer than maple. Again, up to you.
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I've never had any luck with birch of any kind. The tree hates me. It always fails in compression, so maybe a good idea would be to trap the back? Just a thought.
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A bend test will help decide that, too. It goes beyond general wood specs to what's at hand.
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From Google...Betula Pendula, Pubescens