Last year the U.S. Postal Service did a stress test on one of our Greenland paddles and broke it in half, right at the shoulder, where the loom (handle) meets the blade.  I cleaned up the break and reforged the paddle using epoxy thickened with cedar dust, encased the fracture in a fiberglass sleeve, named it Anduril, and paddled with it all summer long.  
 

Anduril after the first reforging.
 
Then, at the pool this winter, the paddle broke again while I was recovering from a sculling brace.  When I got home, I pulled the paddle apart and found that the joint was epoxy starved.  I had used regular epoxy and I suspect that enough of the epoxy drained out of the joint while it was curing overnight and weakened what should have been an unbreakable joint.  The fiberglass had held it for a while, but over time the stress was too much and it tore all the way through, all the way around.
 
So, now it's time to reforge the paddle again.
 
 
 

Is it getting shorter every time?  What is the overall length compared to new?

if you haven't epoxied the sheathing on yet, i could glue/inlay a 1/2" thick spline of ash through the break the next time you're here.  it would definitey make the joint much more fail-safe.  it would take much time either.

Sliding the Kevlar/Carbon sleeve over the paddle.  

 
 
 
Showing the difference between the size of the sleeve and the paddle shaft.  It's a three inch sleeve and the paddle shaft is about 1 3/4 inches across.

 
 
 
Pulling on both ends of the sleeve snugs it down to the size of the shaft.

 
 
 
The Food Saver:

 
 
 
Using epoxy to wet out the sleeve.  I used a lot of epoxy because kevlar and carbon fiber are both known for being difficult to wet out.  Plus, the vacuum bag would squeeze out the uneeded epoxy.

 
 
While it's brown in the bucket, the epoxy dries clear.

 
 
Vacuum bagged:

 
 
You can see the excess epoxy squeezed out to the sides:

 
 
After the paddle is removed from the bag, the extra epoxy makes it look as though it still is in the bag.  The excess resin tears off easily and then is trimmed with a knife or a sander.  I used a saber saw to trim the kevlar from the ends of the paddle.

 
 
Putting on the finishing coat of epoxy.  Foam brushes are a bad idea for this step because after you've smoothed out the epoxy for the hundredth time, the foam brush starts to disintegrate and leave little black foam pieces in the epoxy, which requires more sanding later.

 
Well, I gave Anduril it's inaugural paddling this evening, rolled with it several times and did a lot of bracing.  It has almost no flex, and feels like you're paddling with a steel bar as opposed to a piece of wood.  I mean that in a good way, although, as some have noted in the past, there's something nice and warm about a piece of cedar in your hands as opposed to a composite paddle.  
 
But, I give it two thumbs up.  I even made my offside roll with it this evening, which is a first without wet exiting or having to switch to the strong side to come back up.
 

Welcome to our forum!  I checked out your paddles on your website.  Very nice.
 
It sounds like you got into business much the same as we did, too expensive to buy, so make it yourself, then make them available to others.
 
As to how it performs, I use this paddle almost exclusively.  I hate to scratch up my "pretty" wooden paddle.  I don't worry about it with the CF/Kevlar paddle.  I also like the fact that there is no flutter or flex when I scull or roll.  It feels as though all of my effort is transferred to the water.  
 
The CF/Kevlar sleeve is 9oz fabric.
 
The edges are as sharp as the paddle that I used for the core, which is pretty sharp, although I haven't measured it.
 
We're planning on making a foam cored paddle using the same method.  The strength of the core shouldn't make much difference once the cloth and epoxy are together and set.  Some guys make hollow cored paddles using carbon fiber.  If I were worried about it I would use two sleeves, maybe a lighter fiberglass sleeve, then the CF/Kevlar over that.
 
Keep us posted on how it turns out.