How to size down a paddle blade?

[corrego]

I have a decent but old carbon blade which i want to size down for my kid. Basically i want to make the blade area smaller for him.
Can this be done?

like cutting sides so the are si smaller? anyone out there? Sanding?

thanks

[PonoBill]

Sure. Inside the blade is a foam core. If you don't cut into the core you're done. If you do, then dig the foam out to give yourself a margin--about half an inch, fill with epoxy and clamp it tightly with wood strips and clamps. Might leak a little, but the foam is generally not water absorbing. Evan Leong did this years ago to make hig aspect, small paddles for himself--ahead of his time. And I've done it to make kids paddles.

[corrego]

what tools did you use?

thanks

[Bean]

If you have a paddle blade with a workable edge of 37", for every 1/16" on average, that you shave off you will reduce the paddle area by 2.3 square inches. 

A stationary belt or disc sander would be the best tool.  Set a marker in a compass or use tape to get your line perfect.  If your paddle has 1/16" to 1/8" to give this might be a fun project, on the other hand if its a high quality paddle and you go right to foam, as PB already eluded, this could be a much bigger project.

[PonoBill]

what tools did you use?

thanks

You can cut it with a hacksaw, but a multitool or angle grinder works better.

[Bean]

good one PB!

[supthecreek]

Wear a mask when cutting, sanding or grinding carbon!

[PonoBill]

For sure. Every time I grind or cut Carbon I think of John Brittan, who built the most innovative motorcycle of his time, but died from the effects of breathing carbon dust. He just didn't know--no one did back then. but now we do. Mask and goggles, always. And gloves are a good idea. If you get a carbon splinter it's a bitch.

[PonoBill]

For sure. Every time I grind or cut Carbon I think of John Brittan, who built the most innovative motorcycle of his time, but died from the effects of breathing carbon dust. He just didn't know--no one did back then. but now we do. Mask and goggles, always. And gloves are a good idea. If you get a carbon splinter it's a bitch.

Officially John died from Melanoma, Unofficially it was probably Carbon. Amazing guy. the ten bikes built are essentially priceless since no one who owns one needs the money they might logically be worth.

http://www.motorcyclenews.com/news/2016/july/whatever-happened-to-the-britten-v1000/

[krash]

I recently did just this, but for other reasons before I got into paddleboards. I stand up sight fish and was using a solo canoe... After using a borrowed SUP for a couple months liked the SUP paddle. Picked up a used, supposed full carbon, dinged up paddle from a local SUP rental outfit  figuring I could easily repair it with Epoxy.
Sanded rough edges and dings, filled with thickened epoxy, sanded smooth and started using it quick and easy. After several uses I found the paddle to be blade heavy and thought it was more blade than I need.

Went to work and after researhing, google, blade shapes and sizes decided on a shape. Traced out the existing blade on stiff paper, did a lot of measuring and fiuring and came up with a plot of what I liked, added some cut lines to the paper til I like what I saw. Folded the paper in half and cut it so both edged had an equal shape.
Used masking tape to tape up the edges, both sides, of the paddle blade... taped down the paper shape and marked the outline on the masking tape as cut lines.

Used my handy jig saw and cut the outer edge off the blade... removed the masking tape, and sanded the jaggies off with some 80 grit paper.

Even though the blade was sold to me by the rental operator as full carbon, it looked like carbon, I found the blade was filled with foam... looked like carbon sammich with foam in the center.

Went to work finishing it off, first attempt was to use glass cloth and line the edge's but did not like the finished product as the glass cloth buched up and did not form to well so that got sanded back off.

Cleaned up the edges again and start over, if I did it again I'd dig out a bit of the foam as suggested above.

Added a layer of thickened epoxy adhesive, or two, sanding in-between with 120 grit paper. When I had a nice secure looking edge, started with the finished edge work. Mixing and adding some ground carbon dust to pigment the edges for a pretty good carbon matched color.
Fortunately I have a fishing rod rotating device used when epoxying the guide's, with a few adjustments I as able to get the paddle shaft into the jaws, so that I could spin the paddle while the epoxy dries giving a pretty clean and smooth finish.
Otherwise the epoxy sags, gravity is not always your friend, while curing.

My personal choice of epoxy is G-Flex for the thickened requirements, and West Systems for the finish work.

Finished it up by sanding with 120, then 220, then 320, followed by 320 and 600 wet sanding, looks better than new, at least until the first time you push off form a rock or into the sand. But it worked well... I use that paddle still today when in the canoe, even though since then I've gotten into the SUP side and have a couple very nice full carbon paddles, recently got a QB.

If I refinish that paddle again, I will dig out a little of that foam, perhaps a 1/8th inch, and take some glass cloth, strip out several strands of glass, or perhaps carbon fiber, soak in epoxy and fill that edge making a seriously hard rock guard edge.

[PonoBill]

Full carbon means all the composite is carbon, not that the blade (or the shaft for that matter) is solid all the way through. BTW, if you cut a carbon shaft and sand the edge with fine sandpaper, you're likely to see varied layers. In many cases the shaft is fiberglass with one layer of carbon. there's nothing wrong with this, other than incorrectly calling it "full carbon". Most folks wouldn't want full carbon--depending on the weave and the thickness of the shaft wall, it would flex about as much as a steel pipe does. Maybe less.