Hollow building a
bamboo fly rod means exactly what you'd expect:
Material from the inside of a bamboo rod is removed
leaving open spaces within. The purpose of removing
the material is to make the rod lighter in weight
and make it rebound and recover quicker with less
bounce and excess vibration.
There are many methods of hollow building. Most
methods have disadvantages, the most severe being a
significant reduction in the overall strength of the
rod. I have experimented and made rods with every
type of hollowing I could find - straight-cut,
fluted, star-hollowing and scalloped. |
 |
| Solid Cross
Section |
|
 |
| Straight-cut Hollow |
|
 |
| Fluted Hollow |
|
 |
| "Star" Hollow |
|
|
|
After testing these
rods I have come to the conclusion that the best
method, for both improvement in action and overall
strength, is a method first described and developed
by EC Powell.
|
Click here to see Powell's original October 31,
1933 patent. |
Simple scalloping involves removing small ovals of
the softer, inner pith of a beveled and shaped
bamboo strip. By mirroring the ovals on each of the
6 identical strips of a hexagonal rod (or 4 strips
for quads) you end up with small hollow ovals inside
the finished rod. This method of manufacture is, as
a friend put it, the closest to "OEM specs"
of a bamboo culm. In other words, like a culm of
bamboo, there are hollows that are reinforced by
dams throughout the length of the culm.
Of course that is not
the end of the story. The next step is to vary the
length and wall thickness of the scallops, or
hollows, inside the rod in order to improve specific
desirable qualities. Longer, thin wall scallops are
better suited for the thinner tip portions of a rod
while shorter, thicker walled scallops keep butt
sections from becoming weak or too soft. |
 |
| I have designed a complex mixture of scallops with
different wall thicknesses, dam thicknesses and
lengths and optimized their layout for each section
of a rod from under the grip into the tip. This gives,
what I believe, is the greatest benefit of hollow
building while retaining the strength and feel of
bamboo. |
 |
| This photo shows a side view of
a single bamboo strip that has been
scalloped (approx. 1" long). |
|
 |
|
This photo shows what half of a rod
(3 strips from a hex rod in this
case) looks like when scalloped and
assembled. |
|
|
|
|
