Primitive Archer
Main Discussion Area => Bows => Topic started by: butch on August 12, 2011, 11:10:44 am
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how do i thin 2" wide strip down to 1/8" to apply onto a 2" wide board bow. i have a 10" disk / a 1" vertical belt / and an orbital sander . have not thinned boo before. thanks.
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I use a block plane, be careful with your depth setting. Once I get close I switch to a sanding block and 80 grit to finish it off. Wear a dust mask, boo dust is nasty and very fine.
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Pearl, what do you use to rest/lay the boo on and deal with the crown? I assume if you are planing with a block keeping it "square" and level is fairly important? Does it splinter worse with the block vs say a belt sander approach?
Thanks~
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I use wood spacers bewteen the nodes and bar clamps lightly snugged down over the nodes, just enough to keep it from sliding. I have tried jointers and sanders and ruined my boo each time. Thats why I do it by hand now.
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Gotcha...haven't worked with Boo yet and was likely gonna start with the sander or joiner but maybe i won't know. Don't have a block plane but guess it's a good time to look for one. Thanks PD~
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There is more to be careful about boo than the dust.
If you thin it down to"nothing" it creates a wickedly sharp edge,i cut my hand pretty bad straight through a leatherglove doing that.
Nice stuff but handle with care ;)
/Mikael
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With that Pearl I had a quick question with thinning the boo. Last time I thinned any down I did it when I was visiting my parents on my Dad's jointer. I had good success except naturally the boo is thicker at the nodes. Is it alright for it to be thicker there at the node? Or should try to thin it down there as well? The only thing I worry about is then I won't get a good seal when gluing up because it isn't flat. I typically set the jointer really low, I think it probably took us 20 or more passes to get it down but I'm fine with going slow because it's probably still faster than I could do it by hand and more uniform. I have a distinct feeling I'd hack it all up with a block plane.
~Barry
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The glue side of the boo needs to be flat as a pancake and not cupped at all. Leave the node area thicker, no big deal there.
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Cutting through the bamboo nodes (back/rind) is equivalent to cutting through a knot, you leave end fibers exposed and they will more than likely lift. You can remove the rind to more readily have the bamboo take stain etc...but be careful near those nodes! Cheers, P1.
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can anyone answer the original question on will a 2" wide boo still reach across a 2" wide board after its thined to 1/8" thick. maybe i should use hickory instead. also whats a strong lbs. to exspect out of a straight grain red oak board 70"ntn. bendy handle, 40" 2"wide, and 15"from the tips tapered to 3/8" nock. presently pulling only 40 lbs. at 22" draw. i want to get to 28" and 60 lbs. thanks
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Butch you won't be able to thin boo enough to go on a 2"wide bow. ...and IMO red oak is not a good choice for a boo backing. Boo is very strong in tension. You want to use the strongest in compression wood you can get for the belly of a boo backed bow.
Generally if you reduce a boo backing strip to 1/8" at the crown at the handle the boo strip will not be much wider than 1 3/8". You can trap the belly(make it wider than the back,trapizoidal cross section) and get a little more bow width but not much.
Hickory on the other hand makes an excellent bow backing, not quite as sexy as boo but a good backing none the less.
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thanks pat. i was hopeing you were around.
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Butch you won't be able to thin boo enough to go on a 2"wide bow. ...and IMO red oak is not a good choice for a boo backing. Boo is very strong in tension. You want to use the strongest in compression wood you can get for the belly of a boo backed bow.
Generally if you reduce a boo backing strip to 1/8" at the crown at the handle the boo strip will not be much wider than 1 3/8". You can trap the belly(make it wider than the back,trapizoidal cross section) and get a little more bow width but not much.
Hickory on the other hand makes an excellent bow backing, not quite as sexy as boo but a good backing none the less.
For the sake of argument...all of my bamboo backed bows have turned out really well. :P
I use a block plane as well. How thick is the crown? If it's over 1/8"...might get away with 3/16"...then I have to go with Pat. If it's too thick it will overpower red oak in a heart beat.
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I know a red oak bow can be backed with boo but for the sake of argument red oak is not the best choice for a boo backed bow...and especially for someone that is not even familiar with making a boo backed bow. Use the strongest in compression wood you can find!!!
The areas under the nodes will be a bit stiffer than the rest but getting proper tiller with a boo backed bow is all in finessing the tiller even though the nodes will affect the bending shape of the limbs.
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I know...I was just picking...I started out with heavy glass, though, so figuring out how to make bamboo work on the red oak wasn't too different for me. I agree with you, it's not ideal, especially for a first or early go.
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I want to buy a stationary belt sander. but I don't have one so this is how I do it. Block planes are kinda short but I guess will work. I use a jointer's plane that I got for $40 at an antique store. An extra HOCK (check the website) blade and 30 min of tuneup time and it's a work horse for me. I couldn't build bows with out it. the stock blade I reground to a VERY shallow crown. Skew the blade and take diagonal cuts and you have a gentle scrub plane for hogging off wood . . . kinda.
Back to boo flattening. I set the rounded blade to the widest part of the curve and set it pretty shallow then work it deeper in stages of like 1/64 till I'm happy.
I clamp the boo with a piece of bike tire tube under it. You should be able to get it for free from a bike mechanic. Or you could use two strips of the bike handle bar wraps laid side by side. Used is also free from bike mechanics. The crowns will cause high and low spots that wont sit still. I put a shim under the section I'm working on at the moment. Wax the sole of the plane to get a good slick glide with paste wax. Work slow and check often. I also precut the bow shape for the tips then re-thin and flatten those. There will be some tearout around the nodes unless your blade is "Scary Sharp" which I recommend (google that). I then use the disk from an angle grinder for sanding aluminum. 35 grit or something seriously coarse like that. Hand sand to get the plane facets out and blend out what little tearout you will have. I don't sweat a little tearout because I'll be using a grooving plane later anyway. Don't skimp on the glue. Get it in all the grooves and what little tearout you have.
If you have a belt sander then look up a website "poor folks bows" and read the bamboo backed Ipe build along.