Building a Carbon Fiber
By Duane Strosaker
From plug, to mold, to paddle.
Greenland paddles are traditionally made of wood, which has been a
good material for making them. But the carbon fiber
made by Superior
Kayaks, Inc. intrigued me, so I ordered one.
When I opened the package, I was awed at the beauty of the paddle.
The modern material
wonderfully complimented the traditional design. Being the home builder
I am, I just had to build my own carbon fiber Greenland paddle.
Building this paddle isn't much different than
building a composite kayak. Like the deck and hull of a kayak,
the pieces of the paddle are molded and then assembled at the seams,
which is a construction technique found in almost any fiberglass
manual. But before any molding
to be carved,
and from it,
a mold is formed.
I don't know how Superior Kayaks, Inc. is able to beautifully
assemble the molded pieces without any apparent (as far as I can see)
reinforcement on the outside of the seams and still make the
paddle so strong. I wasn't about to cut into a perfectly good
paddle (now $475 and worth every penny) to find out how they do it,
so I settled for making my paddles using the common technique
composite reinforcement on the outside of the seams, and they turn
out pretty nice.
Building the Plug
The carved blade half.
Building the plug starts like carving any wooden Greenland
paddle, except that only one side of one blade and the loom
is made. The other side is flat. Make sure that the edge on each side
the blade is exactly like the opposite side so that the two
halves of the
fiber blades will meet perfectly at the seams when they are joined
back to back. Also, avoid making sharp curves that the carbon fiber
will have troubles forming around.
The directions I recommend for carving
a wooden Greenland paddle are by Chuck
Holst at the Qajaq USA website. Matt
Johnson has an online video on how to carve a wooden
Greenland paddle using Holst's directions. Brian Nystrom has a book
on building Greenland paddles that you can order online at
My own Greenland paddle specifications are at this link.
The plug and flange.
The plug needs
a flange, which is simply a flat piece of wood that is epoxied to the
Be sure to read and study the user manual for the brand of epoxy being
used. Before epoxying the blade half and flange together, coat
them with epoxy and sand them smooth until they are shaped perfectly.
After the epoxy has cured, apply
five coats of Johnson paste wax to the
plug (and flange) so the mold won't stick to it. Then, for the
same reason, brush on a coat of PVA mold release and
dry before building the mold.
Building the Mold
Layers of fiberglass over the plug.
The mold is built
by applying layers of fiberglass to the plug. Along the sharp corners
of the plug, which is between the blade half and flange, apply a fillet
of epoxy thickened with colloidal silica filler, because the fiberglass
cloth won't bend that sharp. Apply a
of six ounce fiberglass, let the epoxy cure, and then add
two layers of 1 1/2 ounce chopped-strand fiberglass mat to stiffen
Make sure the chopped-strand mat used is compatible with epoxy resin.
The plug and mold.
allowing the mold to cure, pull it off the plug. Then
prepare the mold like the plug was with five coats of paste wax and
one coat of
mold release. To prevent the mold release from forming a puddle
in the mold, set the mold vertically on the loom end, until the mold
Now that you are done with the plug, hang it up in your home as art.
Molding the Blade Halves
The lay-up wetted out and squeegeed on wax paper next to
Because the mold
is a small and curved area, wetting out the lay-up with epoxy
is easier on a sheet of wax paper on a flat surface.
The lay-up I prefer is four layers of 5.8-ounce plain weave carbon
which results in a finished paddle weighing approximately 20 ounces
and having the same amount of flex as Sitka spruce. Carbon fiber
also comes in twill weave, which looks nicer and actually forms slightly
better around curves, but it doesn't hold up as well as
into the mold. Wet out the
first layer of carbon fiber, put the next
continue until all four layers are wetted out. Then
a squeegee to remove the excess epoxy.
lay-up is peeled off the wax paper and placed in the mold with the
smooth/wax paper side of it facing down. Trim the
lay-up with scissors so that only around one-half-inch
of it is sticking up from
the mold firmly and evenly, and press out all the air bubbles between
the mold and lay-up. Use acetone to clean the epoxy off the scissors
The lay-up in the mold after the initial trimming.
Final trimming with a razor blade before the epoxy has fully cured.
Before the epoxy
has fully cured, the final trimming of the lay-up in the mold is done
with a razor blade held flat against the flange edge.
This step must be done when the epoxy has stiffened some and
is still slightly sticky. Depending on the type of epoxy used and the
temperature, reaching this curing state can take from one to six
hours. Use a single edge, steel backed razor and keep it
angled toward the flange during the cut to prevent the lay-up from
being pulled off the mold.
off the mold. The blade half pops out easily by just bending
the mold. Wash the blade half with water to remove the mold
release from it. Four blade halves are needed for one paddle. Between
half, wash the mold with water, dry, and apply a coat of paste
wax and mold release.
The blade halves won't be perfect. Sometimes
the razor drifts downwards and cuts the carbon fiber slightly below
the flange. After the blade halves
to back, these small voids in the seam can be filled with
epoxy and sanded smooth. Also, occasional spots
on the outside surface of the blade will have tiny voids where
air was trapped between the lay-up and mold. As you continue building
the paddle, fill these voids with epoxy and sand smooth.
Assembling the Four Blade Halves
Clamping the blade halves together with rubber bands.
the seam edges smooth, apply epoxy to the them, and clamp
the blade halves together with rubber bands until the epoxy has cured.
Before the epoxy begins curing,
is important to make sure the seams are straight and
that there is no twist in the blades.
Reinforcing the seams with 3/4 inch bias-cut carbon fiber strips.
Lightly sand 1/2 inch to each side of the seams. Then
use 3/4 inch wide strips of bias-cut carbon fiber to reinforce the seams.
This bias-cut is done diagonally at a 45 degree angle across the weave,
and it is stronger because each strand crosses the seam. More importantly,
around the edges of the blade. You may be tempted to use composite tape,
but it won't form well around blade edges. Use a brush to apply
epoxy to the seams, and then lay the strips on top. Apply additional
to the strips to fully wet them out by dabbing with a brush. When
the epoxy has cured, apply two coats of epoxy over the strips to fill
of the strips to feather them smoothly into the molded blades. Try to avoid
sanding into the carbon fiber in the molded blades.
Use a miter box
for a straight cut at the loom end of each piece, which will
be the center of the paddle.
Closed-cell foam plugs (which serve as silencers)
before being inserted into the looms.
While the perfect Greenland stroke is silent, not every stroke
is perfect, and air ventilating behind the blade makes a scratching sound,
which will travel loudly through a hollow paddle. To make the paddle as quiet
as a wooden one, insert closed-cell foam plugs into each loom just before
root of the blade. To help keep the plugs in place,
coat the sides of them with epoxy.
Then after the plugs are inserted, point the looms straight up, and drop
some shredded fiberglass and epoxy on top of the plugs to form bulkheads.
Assembling the Center of the Paddle
Epoxying the two ends together at the loom.
The center of the paddle is assemble on a board
to make sure the paddle is straight and not twisted. I make the board
perfectly flat by adjusting how it's nailed to an old strong-back.
On the board mark a straight
to each side that match the thickness of the loom. Also mark the center
of the blades to line them up with the centerline on the board.
Using small pieces of wood, raise the tips of the blades equal to a
distance half the width of the loom. Use a level
to check for any twist in the blades.
Join the two ends of the paddle temporarily at first by sanding to each
side of the seam, coating the seam with epoxy, and applying a one inch wide
and two inch long piece of carbon fiber to reinforce the top two-thirds of
the seam. Before the epoxy begins curing, make sure the
twisted. Allow the seam to cure 24 hours before gently handling the paddle.
twisted. Now is the time to bust the seam and rejoin if necessary.
The center seam wrapped with carbon fiber, wax paper, and masking tape.
When the seam is ready to be fully reinforced, sand
to 1 1/2 inches of each side of it. On wax paper wet out a three-inch-wide
strip of bias-cut carbon fiber long enough to wrap the loom four times.
Peel the carbon fiber off the wax paper and wrap the seam. Then wrap
the carbon fiber with wax paper and masking tape in the same direction
that the carbon fiber was wrapped. Allow the seam to cure for three
days before applying any pressure to the paddle.
Sand the paddle smooth with 220 grit sand paper. Then
apply a thin coat of epoxy. After the epoxy has cured, roughen the
paddle for the perfect grip by wet sanding with 400 grit and rubbing
it with wet "0" synthetic
steel wool. It is not necessary to finish the paddle with varnish.
Materials for the Plug, Mold and Paddle
- Wood for plug and flange, 3/4 inch thick, 6 inches wide, 9 feet
- Fiberglass, 6 ounce, 50 inches by 10 inches
- Fiberglass chopped-strand mat (compatible with epoxy resin), 1
1/2 ounce, 50 inches by 20 inches
- Carbon fiber, 5.8 ounce, plain weave, 50 inches wide by 3 yards
- Epoxy resin and hardener, 2 quarts
- Colloidal silica filler for epoxy
- Closed-cell foam, 4 inches by 2 inches by 1 inch
- Johnson paste wax
- PVA mold release
- Wax paper
- Razors, single edge, steel backed, at least 4
- Acetone for clean-up of brush, scissors, and squeegee
- Sand paper, 60, 100, and 220 grit
- Synthetic steel wool, "0" coarseness
- Latex gloves to protect hands from uncured epoxy
The Point Bennett Sea Kayak
Greenland Paddle Specifications
Carbon Fiber Greenland Paddles Built
Carbon fiber Greenland paddles built by Rune
Rune later built
a third one.
Magnus Lindquist in Sweden built this carbon fiber Greenland paddle.
Ross Leidy vacuum bagged this carbon fiber Greenland paddle. See his
The Point Bennett Sea Kayak
This page © Copyright 2005-2012, Duane Strosaker.
All rights reserved.