Author Topic: osage board bows: 2 at once  (Read 60452 times)

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radius

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Re: osage board bows: 2 at once
« Reply #75 on: April 04, 2008, 07:09:41 pm »
thanks!

I've never worked with bamboo or osage before...maybe I should just wait til it's a bit warmer outside and epoxy the damn backing on before going any further!

You are very diplomatic, btw.

Offline Gordon

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Re: osage board bows: 2 at once
« Reply #76 on: April 04, 2008, 08:59:22 pm »
I asked the question because I cannot think of any good reason to subject the board to the rigors of the short string before gluing on the backing. I only see downside - unnecessary work (you will have to tiller again after the backing is applied), potential set and even breakage if the board is ill-suited to be a selfbow or is not prepared properly. You really only need to get the board bending enough so that any reflex (or deflex) that you glue in is evenly distributed along the length of the limbs and it looks like you already have that.
Gordon

radius

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Re: osage board bows: 2 at once
« Reply #77 on: April 04, 2008, 10:42:06 pm »
ok, thanks Gordon...i admit it:  i was impatient to get the bow into shape....there, i said it!

All that other stuff about experimenting and keeping it new is also true, but hey!  No point in re-inventing the wheel.

Tomorrow I will glue the bamboo onto the back.  Today I salvaged an old inner tube which i can cut into two long strips...i'll put a little reflex into it, and we'll see how it goes from there.


radius

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Re: osage board bows: 2 at once
« Reply #78 on: April 05, 2008, 07:02:16 pm »
OK...

This morning I spread tarp on my floor to do my glue-up inside...Gotta love the smell of that epoxy!  First of all, I did a dry run.  Went into a bike shop yesterday and asked if they had any used old tubes headed for the garbage, so they gave me a large one which I cut into two strips about 6 feet long...

Here is the dry run...





This is the epoxy I have been using...this one has never given me any grief at all...it's especially designed for oily woods, so I did not bother to wash the back of the osage with acetone...I know, it's sacrilege!



Here is the bow fully wrapped.  The handle has stretch wrap on it, and so does one tip...



And as an aside, here are three photos of a splice I've done for a kids bow, made from the pieces I cut off the belly of this bow...My handcut z-splice was not so stellar, and I tried a trick I've read about on some forum or another:  mix osage sawdust and file shavings into the epoxy.  The center cuts received this thickened/reinforced epoxy, while the outside cuts received clear epoxy.  We'll see!!!







Today is Saturday, so I will let the epoxy cure for 24 hours, and then we'll let ya know!

radius

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Re: osage board bows: 2 at once
« Reply #79 on: April 05, 2008, 07:31:48 pm »
You can all see my reflexing form over there...but I didn't use it this time.  I have been hauling on this thing, well over 65# pressure at about 15" draw...and it is as straight as when I first started working on it...so i'll save the reflex form for the thinner pieces I sawed down earlier...

radius

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Re: osage board bows: 2 at once
« Reply #80 on: April 06, 2008, 03:02:35 pm »
The clamps and straps are off, and you can see the gluelines in these next few pictures...fortunately, I have to go out today, or I would probably not be able to resist working on them further.  The epoxy has set, but it wouldn't hurt to give it a bit more time, right?

Man, I'm not even done yet and I already agree with Pat B:  bamboo is more trouble than it's worth, when a simple strip of hickory is so much easier to produce and work with!







You see the bamboo is slightly over at each end...just needs trimming...

radius

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Re: osage board bows: 2 at once
« Reply #81 on: April 06, 2008, 03:04:31 pm »
Oh, and you guys!  You were so right about the effect of the backing strip on draw weight/flexibility:  you saw how much this thing was bending before, but now, with the bamboo, it barely moves at all when i floor tiller it...

radius

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Re: osage board bows: 2 at once
« Reply #82 on: April 07, 2008, 06:14:01 pm »
Hi...

Here are a couple photos of the bamboo-backed bow, after trim-sanding...





Here, you can't see it very well, but either the bamboo was shallow or i missed a spot with the epoxy, but there is a...GAP!  I actually had a slight gap at each end, so I trimmed about a 16th off each side of each end, and that eliminated the problem.



These next couple pictures are of the stave with the huge divet on one side.  The first shows the back marked for demolition.



Now here is the finished product, belt sanded and ready for bamboo.  Be careful when belt sanding these babies:  my handscrew clamp gave way and the stave shot back at full force into the fence!  Make that, the Landlord's fence....



Right now I'm going to epoxy this bow to its backing.  This time I made the backing thinner, and maybe I can get some reflex into it...i'll try it out in a dry run and see how it goes....




Offline El Destructo

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Re: osage board bows: 2 at once
« Reply #83 on: April 07, 2008, 07:28:50 pm »
Man that one Stave has some bad-assed grain Run Off...even Backing it seems to be a Gamble....if it holds...it will sure be different looking with all of them swirls on the Belly....
As a species we're fundamentally insane. Put more than two of us in a room, we pick sides and start dreaming up ways to kill one another.Why do you think we invented politics and religion.
Think HEALTHCARE Is Expensive Now,Wait Till It's FREE
Do Or Do Not,There Is No TRY
2024...We Will Overcome

radius

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Re: osage board bows: 2 at once
« Reply #84 on: April 08, 2008, 06:42:46 pm »
all bowmaking is a gamble, my brother!  After all, what do we do but push the envelope, push it a little more, a little more, a little more...we're like little kids bugging our parents for money, or slackers trying to get out early and  hope the boss doesn't notice!

This is what yesterday's backed bow looks like immediately after trim-sanding the edges:



Yesterday, before adding the bamboo, but after thinning the thing down with the belt sander, I could draw it about 16" no problem, maybe 40 pounds or so.  Here it is today at 8" immediately after trimming.



Spots like this where the grain swirls, you have to change direction with the rasp.  You can do it smoothly with no gouges or tear-outs, provided you change direction with the rasp.  This spot also proves to be a flat area in the upcoming pictures.  It is toward the end of the right hand side of the bow.



At 14" draw:



At 15" draw:  Like I said, the flattish area toward the end of the right limb is where the grain swirls and changes direction.



These next two pictures show the tight string running end to end.  No brace height at all, just a tight string.  The tips of the string are on center, but I can't say the same for the length of the bow.





That's all for today.  How do you guys think I should handle the string issue?  No big deal, just run with it?  Or should I trim the bow width-wise so that the string is centered?  It's a strong draw now, about 70 or 80 pounds at 15 inches, on the long string.  The long string, by the way, is only a few inches longer than the bow itself.


radius

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Re: osage board bows: 2 at once
« Reply #85 on: April 12, 2008, 07:08:41 pm »
Few days later.

I decided to make one bow a pyramid shape, and the lucky winner was...the thicker bow, with shorter fades.  This is not the one with the wane problem I had to belt sand away.

Here is the amount I had to take away, and my edge sander...





After trimming these lines away on both limbs, I put the long string.  It hung to 7 inches.  I pulled it to 12.  Even tiller.  Well, pretty even, anyway.






Took it to the scale:  50 # at 12 inches with the long string.

Since then I've taken it to 15 inches with the long string, using the block method to keep the curve even.   When I get it so that I can pull it 10 inches from where the long string hangs, I will----gasp---affix a short string, at long last.


radius

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Re: osage board bows: 2 at once
« Reply #86 on: April 21, 2008, 01:38:16 am »
Now it's been several days since posting to this buildalong, because i've been busy with my firehawks.  But today i found some time to work on the tiller of this pyramid BBO, and i've got it braced at 4.5 inches.  From there, I can draw it to 23"...70# at 23... the tiller isn't dead-on, i need to remove some wood from the first 8 or 10 inches out of the fades...but i'll get 70# at 28" no problem, and that's what I was shooting for to begin with.



Look at this photo.  I wanted to use a reduced handle area.  I'm one of those guys, who when I see that everybody does something the same way all the time, I like to question it.  I try new things.  But now that i'm there and got it braced, i don't like it and i see why people make 4 inch handles with 2 inch fades each way.  It's not too late.  I'm going to start working on the handle next session, before tillering, so that I can get the thing comfortable and see where the arrow's going to pass.  I've chosen my lower limb already.  I tend to do that fairly early on...not before tillering, but when tillering in the early stages...

Does anybody else use short handles like this?  What have you found?  Thanks.

radius

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Re: osage board bows: 2 at once
« Reply #87 on: April 25, 2008, 01:45:54 am »
HI,

Well, I finally got one of them tillered to 28"...75# before final sand and tune-up.  This is the pyramid style bow.  I'll get some fulldraw photos in soon. 

Here's a picture of the bow at about 4.5" brace height.  You can see the short, lumpy handle.  El Destructo:  you can see my bathroom scale, piece of plywood, and tillering stick on the bathroom floor!  This picture's for you, amigo!

The bow took about 1.25" set.  That's not too bad.  They weren't reflexed at all:  just epoxied the bamboo flat onto the osage.  I have scraped the skin off the bamboo, and sanded it to 150...smooth as a baby's bum except the nodes...i plan to simply coat the bow with tung oil...

the bamboo has some spalting...see that dark line?  What do you guys think of that?  Is it a weakness or just a discoloration?



Tomorrow after work [see, Keenan:  not TOO badly addicted to bowmaking:  I still go in to work ... 'course I'm thinking about bowmaking all day long] I will shape the handle, cut in a shelf...start the final sanding process...

And then on to the next one!

This post is about 2 BBO's side by side.  The second one is shaped like a Meare Heath bow:  I'll tidy up its lines, tiller it to 75# also, and compare the way the 2 bows shoot.

radius

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Re: osage board bows: 2 at once
« Reply #88 on: April 25, 2008, 01:48:50 am »
o btw...

I started a big renovation the other day:  taking out a thousand window from a derelict department store that's being converted to condominiums.  All the window stools are maple.  Oh yeah, maple baby, and just over 6 feet long.  And yeah, they are coming out.  I see a lot of free maple backing strips in my near future!  Now I know what i can use to back my yew laminate bows... Alright!

radius

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Re: osage board bows: 2 at once
« Reply #89 on: April 26, 2008, 04:37:07 am »




Looks like people are prepping their bamboo backed bows this way for tips.  I'll be putting rosewood on here, probably tomorrow.