Hunting a Bamboo Backed Bow

March 19, 2002

I'm in the first phases of building a Bamboo Backed Osage bow following the instructions set forth by Dean Torges in his video "Hunting the Bamboo Backed Bow".  Go to The Bowyer's Edge for details on the video and Dean's other action.  I cut the slats for this bow last year and got sidetracked with a million other things so I'm just getting to the splicing.  Here are some photos of that.  (I've got the bamboo just about ready but no pictures yet.)

Dean recommends using URAC 185 so that is what I used.  Here's the long version and then a closeup.  I added the pop tarts ad for those of you who really love those things :-)  There's another couple billets being spliced at the same time above the slats.

URAC needs to cure above 65 degrees and it's about 60 in my garage and probably gonna get colder.  I added some heat for good measure.

And tucked it all in for the night :-)

March 20, 2002

The splice was successful and I ended up with a nice place to glue some bamboo.  Here it is with the pattern for the bow laid on it.

Bamboo Preparation

I started with this...the new bamboo (as opposed to the old bamboo)

According to Dean, we should prefer the bamboo that has the widest space between the nodes.  Using this reasoning, I should choose the one on the right in the rightmost picture.  The next step is to get the piece flat so that we can lay a pattern on it.  Here's how I started that process.

Before the flattening, you can see the difficulty we would have in laying out a pattern.  Also, notice the dots which get progressively denser as you go towards the rind.  These are the fibers that give the bamboo it's incredible tension strength.  Dean calls them "power fibers"  I used a bandsaw to get the 'boo down fairly flat.

And a belt sander to finish the job.

The next step is to place the pattern in a position that best spaces the nodes along the limbs.  This ensures as even of force between the limbs as possible since the nodes vary in density from the rest of the 'boo.  Bamboo grows its nodes closer and closer the taller it gets so the internodal distance along the bamboo strip varies.  This fits well with our pattern which has a longer upper limb and allows us to position the nodes in relatively the same place on both the upper and the lower limbs.  This creates balance and harmony in the finished bow.  If you look closely, you can see the nodes which I darkened on the left side of the strip. Also, find the lines across the patterns on both limbs.  These are spaced relatively the same on both limbs.  It is difficult to see but I think I did OK.

According to Dean, we also don't want a node within the first few inches of the tip since it will hamper our efforts to string the bow.  After tracing the pattern on the bamboo, I cut it out close on the bandsaw and nailed it with the handplane.  The next step was to scribe a line along the sides that made the side thickness 1/8".  Then a handplane is used to get to this line.

The finished product is a naturally thickness tapered backing that will be a perfect mate for the compressive strengths of osage slats.  It tapers due to the crown of the bow becoming less prominent as the backing gets narrower.  Picture quality is poor but you get the idea.

Prep with a toothing plane (or equivalent) of both surfaces to be glued is next.  And then we get to the neatest part of Dean's system, the glue up.  It is cool.

March 21, 2002

The final steps of preparation before glueup.
Based on the advice of my fine friends at the Leatherwall  I took the bamboo down to 1/16" at the tips and pretty much tapered that dimension to the center which is 1/8".  I also took the slat down to 1/2" in thickness.

I used a microserated butcher knife to prep the surfaces to accept the glue.

And then I built some parts of the system used to get the reflex/deflex shape I am going for.  Dean has a fairly elaborate system but lacking space I decided to go for a little simpler.  It basically consists of a center post that is higher than the two midlimb posts and two endposts that are taller than the center post.


Next step is glueup.  Hopefully tomorrow.
Don't ever believe that making bows doesn't hurt :-)

I really did this as I was watching the final moments of the Indiana Hoosiers win over Duke.  I'm a huge Hoosiers fan and about croaked at the end.  But, ahhh, glory.  It's been a long time coming.

Go to Page Two for the rest of this story.

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February 2002