Glassing softwood paddle - 6 oz or 2 oz cloth?

[Rick]

I found an unusually lightweight western red cedar board at a Home Depot the other day and am going to try making a lighter version of a favorite paddle.

The cedar will be too weak to use on it's own, so it will need to be sheathed in fiberglass on the blade and throat so that there's an outer skin that will be able to take the stresses when power is applied, while still keeping things as light as possible.

Will 2 oz fiberglass cloth be strong enough for flatwater use or should I go with heavier 6 oz? There are fiberglass-sheathed wooden paddles available out there but I'm not sure how they're made... maybe someone here has some idea of how light the fiberglass can be while keeping things strong enough for normal, flatwater use?

Any other comments regarding durability, etc, also welcomed... thanks!

[pawistik]

My understanding is that multiple light layers of glass are better than one heavy layer so how about 2 layers of the 2 ounce cloth for the equivalent weight of 4 ounce cloth - lighter than a single layer of 6 ounce and maybe nearly as strong? Someone with more experience will likely chime in.

Cheers,
Bryan

[Bryan Hansel]

I have a paddle that I built with cedar blades and have coated with 4 ounce tight weave. It's held up fine and I haven't been nice to it. Maybe consider a full covering of 2 ounces and then a reinforcement of an extra 2 ounces on the edges.

I'd be slightly concerned about the shaft, but only because I've broken a all cedar shaft on a GP. It would be interesting to use a fiberglass sleeve to go over the shaft. Of course, you're adding extra weight be doing that.

[Rick]

My thanks to both Bryans for commenting... after mulling things over, I'm gonna go with the 6 oz, I think that most of the weight savings will be in the lighter wood and choosing 6 oz instead of 2 oz will not create that much more weight, percentage-wise. The blade will be thin for flex anyway, so I probably should be going with the stronger cloth just to stay on the safe side.

I also had some concerns about the shaft breaking... I'll give a piece the tried-and-true strength and durability test... ie. step on it, and see how it holds up. If it's too weak, I might rout out a channel on either side of the blank and epoxy in a strip of ash or yellow birch. This will taper out to nothing towards the thinner blade and grip, and it should also balance out any blade-heavy balance problems the fiberglass might create...anyway, we'll see...

[ealger]

Ya know, what would be interesting is when a paddle shaft is fabricated to cut the blank down the center lengthwise and epoxy in a carbon fiber shaft. The shafts can be purchased in hobby shops and come in 4' lengths and various diameters from 1/16" to 1/4" or more. I also believe they are available in archery shops. Perhaps this technique is already in use?
Ed...

[artistwood]

i fabricated my kayak paddle with a fiberglass/cedar shaft. 4 -1/4" by 1 1/2" strips of cedar laminated with 4oz cloth between layers. none on the outside! the blades are made oc 1/8" cedar with 4oz sandwitched between them. this middle layer runs with the weave running parallel and perpendicular to the blade. then a tip of chopped fiberglass, silica and cedar dust is applied after a 1/8" channel is routed in the tip. i use masking tape and aluminum foil to make a rough mold. then apply some hardwood strips to the edges. shape and sand the blade, epoxy it to the shaft, carve a nice transition between the two and apply BIAS 4oz cloth to both sides, do one at a time, and run the cloth about 4 inches up the shaft. when done, sand smooth and apply 2 more coats of epoxy. final sand, varnish and enjoy.
i have found this process produces the best combination of strength, light weight and flexibility. oh yea, dont forget to give the shaft at least 2 coats of epoxy before varnish...........

[Rick]

Artistwood,

i fabricated my kayak paddle with a fiberglass/cedar shaft. 4 -1/4" by 1 1/2" strips of cedar laminated with 4oz cloth between layers. none on the outside!

Hmmm... my reasoning for keeping the fiberglass entirely on the outside was that the outer skin of glass would be primarily responsible for bearing the stresses resulting from appling force to the paddle. The material at the center can be kept as light as possible and reinforcement wouldn't be essential there, something like the sheathing on a stripper making it strong.

That said, the "very light" piece of western red cedar that I searched for turned out to weigh in at 562 grams after final carving and sanding... heavier than I thought it would be. It's a large long-bladed paddle, so the size alone means weight. The other versions in cherrywood and ash, and carved to exactly the same form and dimensions, weigh in at about 830 and 950 grams. The new WRC version is glassed but not sanded, I'll get around to a fiberglassed weight sometime after New Year's... too busy right now.

...shape and sand the blade, epoxy it to the shaft, carve a nice transition between the two and apply BIAS 4oz cloth to both sides, do one at a time, and run the cloth about 4 inches up the shaft.

I also glassed one side of the blade at a time... I forgot that the epoxy will expand as it cures and that created too much cupping along the thin blade when one side had hardened... I had to sand it off and flatten the blade out again with weights and then re-glass both sides at once. The forces of the expanding epoxy on either side of the blade balanced each other out and it's now flat.

...a tip of chopped fiberglass, silica and cedar dust...

This is probably worth doing on the blade tip that I planed down to about 3/16"... even though two layers of glass offer good protection on hardwood paddles, the WRC will be soft and dent easily.

I don't see this lightweight version in WRC being durable enough for hardcore tripping, it'll be a light and flexible, whippy paddle for relaxing at the end of the day, reducing fatigue on long flatwater days, etc. Your method will be stronger and I just might use it on another, more durable version... thanks for commenting!

More to come in the New Year and spring when I actually get to try it out... Merry Christmas and all the best in the New Year everyone!

[artistwood]

i use a curved mold made from laminated 2x6's, faced with a 1/8" white faced hardboard and held together with clamps for the curved blades. i use hardboard covered flat 2x6's for the flat ones. you can design as much or as little flex in the blades as you wish. by putting the glass in the middle running with the blade and the glass on the outside on a bias, you have a double trussed type reinforcement. kind of like having 2 boat hulls together. it is very resistant to flutter and the hardwood edges and the fg tip are extremely durable. as for the shaft, again, i run the center cloth with the length and the other 2 layers are biased. call it estetics, but i like the feel of the wood in my hand. the shaft cross section is a 1" x 1 1/4" oval. the shaft is laminated 90 degrees to the blades. in other words, while holding the paddle, the laminations are flat, the blades are vertical. you can have less flex by adding a heavier cloth on the outside of the blades or use a tapered thickness blade to reduce the flex. i can slam the tips down on concrete and so far, i havent even chipped them. i use brazilian cherry for the edges because of its durability and for the fact that it is easy to heat bend with a heat gun.
i do not run heavy white water and am not a super long distance boater so i don't know what the requirements are for a really great touring, bullett proof paddle. i would like to build one so any advice as far as weight, flex, blade preference, etc would be appreciated. i have my new touring kayak designed so the right type of paddle for the long distances would be great. sounds like paddles are the same as boats....the more and varied we have, the happier we are! thanks......bear

[Rick]

Some final weights for anybody interested..

WRC core...................................... 562g
6 oz glass and varnished........... 691g



The same paddle made from other woods, no fiberglass, with different blade thicknesses for more or less flex.

Cherry............................................ 977g
Ash (thinner blade)..................... 893g


The fiberglass with WRC core gives this latest version a more flexible, springy feel as well as being lighter than the others... I can't say whether the extra work that went into glassing is worth it, since the lakes are all too hard to paddle this time of year.

I don''t think it'll be durable enough for general tripping, hopefully it'll be OK for flatwater and cruising. The darker-toned WRC also looks better than spruce or poplar, which is often used in lightweight wood paddles... anyway, the final verdict comes in after a full day of use on the water, and that's still some time away.