Building Composite Paddles?

[HarryA]

Looking for information on building kevlar & graphite
canoe paddles. Do you know of any books, articles, or
web sites with info?

Thanks.

[Bob P]

Is your plan to go into production or one-off? There's a lot of tooling involved to do a sophisticated design like the Galasport, somewhat less to do a composite layer over a wood core like the Mitchell. I built my own composite paddles for a long time. Finally decided that the small monetary savings didn't compensate for all my labor effort.

[Louie]

Check with Clinch River Paddle company 865 986 9387, ask for William Joseph Johnson and tell him Louie sent you.

[HarryA]

I am thinking of using basswood and balsa
core. I am not sure how many layers of cloth
one needs for the blade; one or more?

True it's more effort than it's worth but I need something to
do while waiting for ice out.

Duane Strosaker has a web site "Building a Carbon Fiber
Greenland [kayak] paddle". He builds a female mold.
http://www.rollordrown.com/kayak/gstick.html

Sweet Composites has:
graphite braided sleeve for the paddle shaft and 94905 hybrid
(an equal mix of Kevlar® and graphite yarns) for the blade.
http://sweetcomposites.com/Kevlar.html

[Bob P]

Layers? It depends on the blade design and how it is joined to the shaft. When I did my curved blades, I used at least 8 separate pieces in each blade half, most of which were partial reinforcements in the shaft cord to distribute stress. My blade halves were individually compression-molded and bonded together in a separate jig. A big PITA process. Hopefully yours will be simpler.

When I sold flat composite blades back in the '80s, I went through 20+ prototypes before I was satisfied with my layup.

If you're interested in stainless-steel reinforcements for the tip (and/or aluminum edge reinforcements), I've got a bunch left over.

[Marc Evans]

HarryA,

I'm probably not the best person for answering your questions, but I've made four balsa wood core, carbon fiber paddles over the last few years. BobP will be able to give you much better advice than I, but I thought that I'd add my two cents.

All of my paddles have had curved blades. I simply layed down one-inch wide by one-eighth inch thick balsa to get a shaft blank that was about one and three eighth thick. I would do this in two halves. Along the way I would lay down a three inch wide by about 18 inch long piece to start the blade, on each half. I would add sides onto these pieces to the desired width of the blade. I would then glue the two halves together and set the bend in blade. You will need to compensate for the bend relaxing after you pull it off the jig to make the bend. I usually just used a series of wood scraps to support the bottom of the blade while weighing down the top to bend it into shape. I used a sandwich of one-eighth thick plywood on top and bottom to keep the pressure reasonably uniform. You will need to build up the blade shoulder with pieces of balsa. Then you can saw the blade to shape and sand. The shaft can be shaped with a block plane (or a large round over router bit). Then sand to a finished blank.

You can hand lay carbon on the shaft. I use strips of plastic bag (white trash bags) to hold the carbon and epoxy in place. I laid three layers (I think) of 6 oz carbon on the shaft. One layer of carbon on the blade and a layer of 4 oz S glass on top of that. I also inserted an aluminum tip in the blade on two of the paddles and tried layers of dynel for the tip on two others. I also put dynel on the blade edges. All of the dynel was laid down before the carbon.

If this sounds like a lot of trouble, it is. Working with epoxy is a pain. Not to mention if you are not careful you will sensitize yourself to it. I have to some degree.

Now for the part I left out. Everyone of my paddles have broken. The first lasted three years and snapped in the middle of the shaft while on a play wave after I flipped. Two of the others snapped at the joining of the shaft to the blade after a bit of rock bashing. I think BobP alluded to this being a weak spot. You need extra layers here, and clearly more carbon on the shaft than the three or four layers I put on. My blades have held up reasonably well.

I'm in the process of repairing all of my paddles. I think I'll try wood next time.

Bob P, did you use epoxy or one of the esters in your paddles?

Marc

[oopsiflipped]

well, not all of your paddles, right mark? one of them, minus the blade, makes a very nice, handcrafted prop for the rear door on my station wagon.

[Marc Evans]

Gabe, I said "my" paddles. Not your paddle, or do I mean - door prop.

By the way, I think that I have fixed your old Werner paddle. It might weigh a pound more than original, but I don't think it will break??? If you make it out this way you can throw it in the car as an extra.

Marc