Possible to make paddle blade stiffer?

-- Last Updated: May-29-12 11:31 AM EST --

Okay, I know the answer is "yes" but I'm wondering if it's practical. First, a description of the problem:

My beloved old Sawyer "Cedar Voyager" paddle has a cracked shaft, and due to the nature of the crack, my ability to repair it is not only iffy, it will be a big project requiring some special tools (like a high-pressure glue injector, which I do not yet have). So in the meantime I bought myself ANOTHER Cedar Voyager, expecting that once I re-shaped that strange new baseball-sized top grip that it would be sheer joy to use, just like the old one, but that has not been the case. The blade of the new one is slightly smaller (probably not a big deal), but in spite of having the same blade thickness as before, the new blade is floppy and bendy. Not only does it feel like a wet noodle when making accidental contact with the river bottom, it buzzes like the reed of a bass clarinet when performing what should be a "clean" underwater slice. That buzzing totally ruins the slicing action because it sets up a lot of extra resistance that shouldn't be there. Since then, my go-to paddle has become my Bending Branches "Expedition Plus", which has terrible performance compared to my OLD Cedar Voyager, but except for being really heavy it actually seems like a pretty good paddle compared to the NEW Cedar Voyager.

So, how can the floppy blade by stiffened without adding "too much" additional weight? Would another layer of fiberglass be enough? I'm sure it would be more effective to add a thin layer of epoxy + micro-balloons and THEN another layer of fiberglass but I'm not sure how much weight that will add, nor do I know if that's a good method. Other ideas? I'm disappointed with this paddle, but the old one was SUCH a nice paddle that I'm really tempted to try to "make the new one like the old one". Comments? Ideas?

By the way, I can't return the paddle because the first thing I did after buying it was to go at it with a sanding block to improve the shape of the shaft, which was both asymmetrical and had the oval shape "off" from the normal 90-degree orientation to the blade. When I get the chance I'll take a close look at the same "new" version of this paddle owned by a couple of my friends. Maybe I just had some bad luck with this particular one.

I’d be inclined to take the blade

– Last Updated: May-29-12 11:58 AM EST –

down to bare wood then glass and epoxy the whole thing. Or better yet, get some carbon fiber cloth instead of the glass. That shouldn't add any more noticeable weight.

I was thinking the same thing. Glass and epoxy on both sides. I hadn’t considered carbon fiber, but it should give a bit more stiffness than the fiberglass.

You don’t have to use glass. You could
use polyester, which is almost as light as carbon or Kevlar of equal weight. You can get polyester from sweetcomposites.com.

On that broken shaft, I repaired a similar greenstick fracture on a Dagger ww paddle. You can inject a thin epoxy like West 105/205 with a dental syringe. You don’t need to get the tip of the syringe into the crack. Just drill shallow holes along the crack (might not need too many holes) which in size are such that the dental syringe tip just fits tight. Then, when you hold it in and squeeze, the resin will be forced into the crack. Usually opening and closing the crack after injection will spread the resin properly within.

I had trouble with the crack that went out sideways re-breaking, even when reinforced on the surface with carbon fiber. So I rested the paddle on its tip and dropped it onto a circular saw blade, creating a semicircular recess across the crack just the size to accept a biscuit I made from Finnish birch plywood. (Not more than about 5/32", maybe less.) I then epoxied the biscuit into the recess.

I stiffened the region of the repair with carbon fibers, covered by a Dynel sleeve. The paddle seems quite strong.

Question on glassing the blade
That all sounds good. The thing is, as near as I can tell, the blade is already coated with fiberglass. So, does a this second layer of glass or carbon fiber really accomplish anything? That’s where my idea of slightly thickening the blade with lightweight filler material came from. It makes sense that a little more separation between the two surfaces would make the fiberglass (or other reinforcing weave) more effective. But if simply adding another layer of reinforcing will do the trick, or the same for sanding off the original layer and providing a better material (perhaps carbon fiber), I’d prefer that.

Crack troubles
I’d planned something similar for fixing the broken shaft. The problem is, the crack goes across the multiple laminations that make up the shaft, and those laminations are aligned at 90 degrees to the blade orientation for greater strength. Imagine cutting a one-inch strip off of a sheet of one-inch-thick plywood made up of about 10 layers, then partially breaking that strip in the “edge-wise” direction, and you might picture the nature of the crack in this paddle shaft. There is no continuity to the crack among all those different laminations, so getting glue into it from the open side simply won’t do the trick. A separate break in each of the multiple laminates is why this paddle shaft was able to “crack” many different times over the last three or four years without any damage showing at the surface, and with no “perceptible” loss of stiffness, until the final time. Anyway, the glue-entry holes will need to go in from the front or back side of the shaft and go deep enough to pass completely through the crack to be sure of intersecting it at some point along the way.

My gut says that adding more glass and epoxy will have to stiffen it up, but probably not enough. My gut recommended that you add some kind of extra spine to the throat and blade area kind of like a surfboard stringer. This could be accomplished without changing the beloved shape of the blade by going at it with a router or sharp chisel very carefully to remove enough material to then add stiffer wood, glue and clamp, and glass over. Voila. And if it doesn’t work, don’t blame me. Blame my gut. I’m just the messenger.

Interesting that they laminated it that
way. Doesn’t conform to either “stringer” or “plate” construction, if I understand you correctly. How many laminations? I don’t think I’ve seen a laminated shaft with more than five layers.

Worth a try contacing Sawyer
I mean, many people mod their paddles. If it is a junk paddle due to the blade, modding the shaft or grip wouldn’t have saved it anyway.

So, IMHO, before you spend money and time trying to ‘save’ an apparently defective paddle, contact the folks at Sawyer. Maybe they will surprise you.

Prefer the Carbon Fiber
I’d experiment first using carbon fiber and epoxy on the entire power face only (unless it’s double power face) and see how it performs in the water. This should do it? Then I’d reinforce the entire edge with more carbon, shape and form it to be almost razor thin. Of course your paddle blade will be a wee bit wider, but how it performs in the water, after modifications, will be superb.

I don’t know the terminology
I wouldn’t know the difference between terms for lamination orientation without looking them up. Basically, the laminations are aligned so that each one of them is stressed in its strongest direction. However, I don’t know if that principle regarding the strongest direction still applies to the whole “bundle”. I haven’t looked at the paddle in a while, and when I wrote the previous post I only guessed at an approximate number of layers in the shaft. I suppose it could be as few as 5, but I tend to think the number is closer to 8.

Of course, with each layer glued to the next, the crack in any individual layer IS roughly lined-up with the crack in adjacent layers, but it’s not anywhere nearly as clean a crack (in terms of forcing glue into the gap from outside to inside) as with a plain piece of wood that’s cracked mostly by means of grain separation. I can’t complain though. I’ve occasionally stressed that paddle pretty badly and it has held up really well considering that it weighs a whole lot less than a conventional wood paddle.

It does have double power face
It’s a straight-shaft canoe paddle, so it’s made to apply power both ways. Does that mean carbon fiber is not such a good choice? I know carbon fiber is great in tension, but perhaps another material would be better considering the dual need of tension/compression. Of course, with the material surrounding a fairly tough wood core, I’m sure the amount of compression is minimal compared to the amount of tension, but still perhaps the use of another material would be better. I’m new at at this stuff.

By the way, the previous blade didn’t need to be sharpened to slice cleanly, and I doubt if the rock guard would hold up so well if sharpened much. I like the idea in principle though, and already DID sharpen the rock guard just a little, hoping it would make a difference (it didn’t).

Good idea
I talked to a Sawyer rep about various other things a few years ago, and I got the impression that they DO make quite an effort to keep the customer happy. I’ll probably see if they have anything to say about this situation.

Carbon fiber is better than glass in
both tension and compression. It has become the de facto standard for facing of competition slalom paddles.

However, some of us still order glass faced paddles because they hardly weigh any more, they are a bit more flexible, and the glass shows any underlying damage. I would not go any lower than 4 oz for glass facing, though. I bought and tried some ~2 oz and it was just junk, good only for aesthetics.

No. The Carbon Will Do Just Fine
Whether on one or both faces. I was just thinking in terms of economy and esthetics. Sawyer’s Zephyr is an example of what I’m talking about with carbon on the power face and the wood grain exposed on the opposite side. Since you got two power faces, and if you cover both faces with carbon, you won’t see the wood, but the paddle will work fine. With the type of paddle you’re using, a razor thin edge won’t make a difference with your style of paddling. Since there is already a thin layer of glass on the blade, adding a carbon layer to both sides would really stiffen it