Bamboo on bamboo

How to make a Bow, a String or a Set of Arrows. Making equipment & tools for use in Traditional Archery and Bowhunting.

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Bormin
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Bamboo on bamboo

#1 Post by Bormin » Thu May 12, 2016 12:11 am

Hi everyone,

Firstly, I apologise if this has already been covered. Just send me to the right thread if it has.

I'm lucky enough to be in an area where I can access tons of bamboo and I'd like to make a 62 or 64" hybrid bamboo back and belly bow.
I have a few questions though.

1. How long does bamboo generally take to dry before it can be split/planed etc?
2. Should the belly be thicker than the back to prevent chrysals?
3. Does bamboo even get chrysals?
4. Should both back and belly be tapered?
5. I have a Bingham Projects 62" hybrid bow form already, would that work just to get the deflex/reflex shape? (I use clamps and rubber tubing)
6. Is natural bamboo strong enough to not require tip overlays?
7. Is Titebond III good enough?
8. Should I get the tiller perfect on both before gluing up?
9. Is it safe to sand the nodes?
10. I also have some vertically laminated bamboo floor boards. Would I be best off adding two lams to the mix to help with the bow keeping its shape?

I think that's all for now at least. I have a feeling the more I find out the more questions I'll have :)

Anyways, thanks in advance for any answers to these.

Cheers,
Bormin

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greybeard
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Re: Bamboo on bamboo

#2 Post by greybeard » Fri May 13, 2016 6:20 pm

Hi Bormin,

It may be helpful if you can identify the particular bamboo as there are over one thousand varieties, and if possible post a photograph of what you have access to.

The following points are from my own experience with making bamboo bows. By all means use them as a guideline but ultimately you will have to draw your own conclusions and make your own decisions.

1. How long does bamboo generally take to dry before it can be split/planed etc?

Splitting the poles when green may reduce the occurrence of random splitting in the pole when drying. I have actually heard the poles stored in my workshop splitting.

2. Should the belly be thicker than the back to prevent chrysals?

4. Should both back and belly be tapered?


I use back and belly laminations of the same thickness and taper both.

3. Does bamboo even get chrysals?

Bamboo can get stress fractures.

6. Is natural bamboo strong enough to not require tip overlays?

No, I would strongly recommend tip overlays.

7. Is Titebond III good enough?

I have had no experience with Titebond as I use two pack epoxies.

8. Should I get the tiller perfect on both before gluing up?

If possible pre tillering can be helpful but more importantly accuracy in equal lamination thickness of upper and lower limb is imperative. I usually work on six inch spacing from centre to tip.

9. Is it safe to sand the nodes?

Remove the rough edges but don’t sand them flat.

10. I also have some vertically laminated bamboo floor boards. Would I be best off adding two lams to the mix to help with the bow keeping its shape?

Vertical bamboo floor boards usually contain a lot of the pith and little in the way of power fibres. It works well sandwiched between fibreglass but can be sluggish when used with pole bamboo.

I believe hard rock maple or hickory, both of which I have used would be a better alternative.

Hopefully the following photos may be helpful.

Daryl.
Node Orientation.jpg
Node Orientation.jpg (44.55 KiB) Viewed 7259 times
Node Spacing.JPG
Node Spacing.JPG (55.28 KiB) Viewed 7259 times
Pole Profiles.jpg
Pole Profiles.jpg (121.26 KiB) Viewed 7259 times
Black Bean Tip Overlay.JPG
Black Bean Tip Overlay.JPG (42.55 KiB) Viewed 7259 times
02 Spokeshaving Pith.jpg
02 Spokeshaving Pith.jpg (51.99 KiB) Viewed 7259 times
Node Placement.jpg
Node Placement.jpg (43.86 KiB) Viewed 7259 times
"And you must not stick for a groat or twelvepence more than another man would give, if it be a good bow.
For a good bow twice paid for, is better than an ill bow once broken.
[Ascham]

“If a cluttered desk is a sign of a cluttered mind, of what, then, is an empty desk a sign?” [Einstein]

I am old enough to make my own decisions....Just not young enough to remember what I decided!....

Bormin
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Joined: Tue Jan 08, 2013 5:53 pm
Location: Port Macquarie, NSW

Re: Bamboo on bamboo

#3 Post by Bormin » Sat May 14, 2016 8:37 am

Thanks greybeard, I was starting to worry i wasn't going to get any answers before the weekend.

Now I have my weekend planned, so thanks again. I'll post pics as i go.

Cheers,
Bormin

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greybeard
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Re: Bamboo on bamboo

#4 Post by greybeard » Sat May 14, 2016 3:05 pm

Hi Bormin,

The following is an explanation of my approach to making bamboo back and bellied bows. No doubt there are other methods of constructing this style of bow but I followed my instincts and trial and error took over.

Once you understand the workings of the simple selfbow the design and construction of a bamboo bow is relatively easy.

Because the back and belly pole bamboo laminations are convex in cross section I find construction easier when gluing up in two or three stages and using two different forms.
09 Open Frame Form.jpg
09 Open Frame Form.jpg (38.57 KiB) Viewed 7221 times
Limb width is generally governed by the diameter of the bamboo pole i.e. the smaller the diameter the higher the crown. For a standard type of longbow three inch diameter poles are ok, use larger diameter poles if you have access to them.

Note that the larger diameter pole is usually cut from the bottom end of a longer pole and the nodes will have a closer spacing. Ideally poles with nodes that are spaced somewhere from 12 inches to 15 inches or more are preferable.

When preparing core laminations for a long bow I have an overall width about 1 ¼” to 1 ½” by the required length. Make a template slightly oversize of the desired limb plan and this will make the marking out of components more accurate and will save you a lot of measuring.

Draw the plan of the limb shape on a lamination and include a centre line down the length and one across at the half way mark. This lamination [back] is placed face down on the form when gluing up.

Using two core laminations, one either side of the riser allows you to end for end the laminations to help minimise weak spots.

I prefer to use three core laminations placing two laminations on the back and one on the belly of the riser.

Split or saw your bamboo pole into suitable widths and start flattening the inner surface with whatever suitable tools you have available i.e. belt sander, electric planer, spoke shave etc.

Mark the limb plan [slightly oversize] on the bamboo and cut to shape. Draw marks across the bamboo at six inch intervals and these will be used as checkpoints to control the thickness and taper. Continue flattening the inner surface until the edges of the bamboo is about 1/ 16” thick.

When the glued up core has cured I cut the plan of the bow, cutting just outside the line. Using the same form I glue the pole bamboo belly to the core.

For ease of construction I use a rigid form to glue up the core laminations, riser and belly bamboo as multiple laminations need a platform to keep them in shape when glued and clamped.

The rigid form will need about five or more inches of reflex built into it as most of this reflex will pull out during the tillering and shooting in process.

When the glue has cured I use the adjustable form to glue up the backing bamboo. At this point you can build in more reflex by increasing post height near the tips and pulling down on to shorter posts inboard of mid limb.
01 Adjustable Form.jpg
01 Adjustable Form.jpg (25.67 KiB) Viewed 7221 times
02 Adjustable Form.jpg
02 Adjustable Form.jpg (31.46 KiB) Viewed 7221 times
I would have second thoughts about building in deflex as this will probably occur naturally with string follow.

Note how much shape has pulled out from the limbs when compared to the form.
12 Solid Frame Form.jpg
12 Solid Frame Form.jpg (16.57 KiB) Viewed 7221 times
Unlike a glass laminated bow that will hold its tiller from the first arrow the bamboo bow may take a hundred or more arrows before its tiller settles.

Changing your 'grip' on the handle can affect tiller.

Daryl.
"And you must not stick for a groat or twelvepence more than another man would give, if it be a good bow.
For a good bow twice paid for, is better than an ill bow once broken.
[Ascham]

“If a cluttered desk is a sign of a cluttered mind, of what, then, is an empty desk a sign?” [Einstein]

I am old enough to make my own decisions....Just not young enough to remember what I decided!....

Bormin
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Joined: Tue Jan 08, 2013 5:53 pm
Location: Port Macquarie, NSW

Re: Bamboo on bamboo

#5 Post by Bormin » Sat May 14, 2016 7:50 pm

Well I'm a fair way away from producing that kind of work greybeard, but I've had a go at pretty simple design which seems to be going ok so far.

I'll take some more pics when I get it on the tree tomorrow.

Cheers,
Bormin
Attachments
and i didn't taper the limbs so they're about 1/4" all the way along. i'm hoping i can rely on thinning the width where needed to get the right shape
and i didn't taper the limbs so they're about 1/4" all the way along. i'm hoping i can rely on thinning the width where needed to get the right shape
4.jpg (128.42 KiB) Viewed 7205 times
not perfectly symmetrical as I didn't use a form and a thousand clamps on this one
not perfectly symmetrical as I didn't use a form and a thousand clamps on this one
3.jpg (126.11 KiB) Viewed 7205 times
the handle is a slim double ended teardrop
the handle is a slim double ended teardrop
2.jpg (136.57 KiB) Viewed 7205 times
it's 59" end to end
it's 59" end to end
1.jpg (92.83 KiB) Viewed 7205 times

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Muz1970
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Re: Bamboo on bamboo

#6 Post by Muz1970 » Sun May 15, 2016 7:55 am

Very curious about this build. Looking forward to see the finished bow

Bormin
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Re: Bamboo on bamboo

#7 Post by Bormin » Sun May 15, 2016 9:31 am

yeah not the prettiest thing out there but the idea was to build a bow using only materials I could scrounge for free.
Glue, bow string and 4 clamps being the only things purchased.

The bamboo used is moso harvested from a nursery not far from where I live.
The nodes are between 10 1/2" and 11 1/2", so a little shorter than what I would have liked.

I'm not 100% happy with the glue line at the reflex(?) bends at the end of the limbs, but if i can keep the weight down to around the 45# mark, I should be ok.

I still haven't decided to cut a small shelf into the handle or shoot off the hand yet.
I guess, in keeping with the simplicity of the build, I'll probably go with the latter.

Pics of it on the tree to come

Cheers,
Bormin

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Re: Bamboo on bamboo

#8 Post by greybeard » Mon May 16, 2016 8:57 am

Being an all bamboo bow it will be interesting to see how much of the original shape is retained in the limbs.

Regardless of the outcome you have had a go and I feel sure that this project has added to your knowledge base.

Daryl.
"And you must not stick for a groat or twelvepence more than another man would give, if it be a good bow.
For a good bow twice paid for, is better than an ill bow once broken.
[Ascham]

“If a cluttered desk is a sign of a cluttered mind, of what, then, is an empty desk a sign?” [Einstein]

I am old enough to make my own decisions....Just not young enough to remember what I decided!....

Bormin
Posts: 27
Joined: Tue Jan 08, 2013 5:53 pm
Location: Port Macquarie, NSW

Re: Bamboo on bamboo

#9 Post by Bormin » Mon May 23, 2016 7:17 pm

Ok, so i've managed to get it to shooting stage.

You can view a vid here https://youtu.be/8Ea5209kd5s, shooting from about 12 metres. At the time taking the video I had put about 36 arrows through it.

I don't have my scales at the moment but I'm guessing the weight to be around 55#
You'll see in the video that it's bending a little too much at the ends of the handle. I don't want to remove any more material from the limbs so i'm going to wrap those areas with wood glue soaked hemp twine to stiffen those areas a little.

Overall I'm really please with how this little powerhouse turned out.
It stacks a bit but arrows just go where you're looking and man it's fast!

More pics when it's finished.

Cheers,
Bormin

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BenBow
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Re: Bamboo on bamboo

#10 Post by BenBow » Mon May 23, 2016 10:08 pm

Looks good and pots them right in there.

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Gringa Bows
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Re: Bamboo on bamboo

#11 Post by Gringa Bows » Tue May 24, 2016 10:06 am

looks good,and really spits them out too

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Forester
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Re: Bamboo on bamboo

#12 Post by Forester » Tue May 24, 2016 7:47 pm

Great job on the bow! I have just found a patch of really big bamboo in my local reserve that I would love to try something similar with when I get the chance. What are your limb dimensions, if you don't mind me asking?

Bormin
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Re: Bamboo on bamboo

#13 Post by Bormin » Tue May 24, 2016 9:18 pm

Thanks guys,

Forester, the handle wood, sandwiched between the two pieces of bamboo is 16" long 6/8" high and was 1 1/2" wide before i started shaping it. The fade starts almost immediately from the centre. Subtly at first then more angle toward the feathered ends, like a thin double ended tear drop.

The limbs are 21" from the end of the fade to the nock and taper in width 1 1/2" to 3/8" at the nock. Probably too thin at the tips and I'll go through some string but hey, she's fast :)
I didn't taper the thickness of the bamboo at all, hoping the width tapering would get the desired shape. I will definitely taper at least the belly piece next time as it bends too much at the ends of the handle as you can probably see in the video. It won't turn out as heavy but should still be enough to hunt with.

This project was really to see if I could make an effective short'ish bow using two pieces of natural bamboo, a bit of spotted gum, glue and a sting. I think I've very much achieved what i set out to do. The hardest thing was actually getting all the waxy stuff off the surface of the bamboo as it really gums up the sandpaper. I did use a planer to get the majority of the meat off the inside wall of the bamboo but everything else was done by hand.

I was actually thinking of just rubbing the handle wood and tip overlays with oil and leaving the bamboo alone. Any thoughts on that anyone?

Hopefully I'll get to finish it off this weekend. If I do I'll post some pics.

Cheers,
Bormin

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Re: Bamboo on bamboo

#14 Post by Muz1970 » Wed May 25, 2016 7:56 pm

Done well, very sweet bow

Bormin
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Re: Bamboo on bamboo

#15 Post by Bormin » Wed Jun 01, 2016 5:40 pm

Ok well, it's done.

Adding the jute string to the ends of the handle section didn't have as much effect on the excessive bending in that area as I would have hoped but it did help a little.
The tiller isn't pretty I'm afraid as you can see in the pics.
Adding the jute made it quite a bit heavier. It's now a smidge over 60#@28", length is 58"n2n.
The next one I do will be 64" and slightly wider at the ends of the handle.
I do like the simplicity of the design and it was never my intention to get scientific with it.
I don't have a chrono so no idea how fast it is but seems pretty quick.

Any constructive criticism is welcome.

Cheers,
Bormin
Attachments
8.jpg
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7.jpg
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The leather lace snapped right at the end so gotta do it again :(
The leather lace snapped right at the end so gotta do it again :(
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4.jpg
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2.jpg
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1.jpg
1.jpg (246.18 KiB) Viewed 7008 times

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Forester
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Re: Bamboo on bamboo

#16 Post by Forester » Wed Jun 01, 2016 7:21 pm

I reckon that is great Bormin. It looks really good and shoots well, and considering your goal was to make an experimental bow with materials you had to hand, I would say that even if the tiller is not as ideal as you planned, it is still a complete success. Good on you!

Bormin
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Re: Bamboo on bamboo

#17 Post by Bormin » Wed Jun 01, 2016 7:29 pm

Thanks Forester.

I get a lot of enjoyment out of making bows and although I wouldn't call myself a fair dinkum bowyer just yet, I reckon I'm getting there.
It's all about the journey so they say :)

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