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Building the Ultimate Expedition Kayak

Planing and Sanding

The kayak hull after planing the cedar strips.

A little work with the block plane made an enormous impact on the aesthetics of the hull. As you swipe the plane along the seams between each strip, the high and low spots disappear and most of the seams vanish as if by magic. Suddenly, a whole row of strips fuses together into a solid, sleek, curved surface and the true curves of the boat become much more visible. Unfortunately, a few stripping mistakes also become more visible: The block plane will suddenly reveal a thin, unexpected gap whenever you plane over a pair of strips that have pulled away from each other even slightly. Sometimes you can plane a little deeper to eliminate the gap again. Sometimes you can't. Fortunately, only a few new gaps appeared in my hull, and most of them were along the centerline where I expected them to be. They should be easy to fill with putty as long as I can find a putty that matches the hull color well. But far more surprising to me was how much the already-visible gaps in the centerline disappeared. I had been disappointed with the not-perfectly-straight, not-perfectly-tight look of my centerline, but once the block plane had taken a few swipes at it, it closed up significantly and looked a hundred times better. You can see how much it changed if you compare the photo of the stapled hull on the previous page to the hull as pictured here. I'm really pleased with the transformation.

While I was planing the hull, I also shaped the stems. As I should've expected from a true hardwood, the ash took a lot more work to shape than the soft cedar strips. Of the three or four hours I spent planing, at least half of that time was spent planing the stems to blend them into the contours of the hull. To ensure I shaped them evenly, I drew a centerline down the middle of each stem and planed off one side at a time. Once you get the stem whittled down close to the approximate curves of the bow and stern, you can use the surrounding cedar strips as a guide to help you angle the block plane properly and produce a nice, even curve on both sides of the stem. Some people would probably trim off the extra length of the stems at this point as well, but since they weren't in the way, I decided just to let them hang over until I started stripping the deck. That way, I wouldn't accidentally trim them too short and end up with an unsightly gap where the stems meet the deck strips.

Another view of the planed kayak hull showing the final shaped bow stem.

A day later, I returned to the newly-planed hull with a bundle of sandpaper, a random-orbital sander (ROS), and my trusty dust-mask. To do the initial shaping and take off the flat surfaces that the block plane left behind, I made a fairing board out of thin, flexible plywood. I cut the plywood to about the same size as two standard-sized sheets of sandpaper laid side-by-side, and attached two wooden blocks (one at each end of the board) to serve as handles. I covered the bottom with two sheets of 80-grit sandpaper and fixed each sheet of sandpaper in place by stapling it along the narrow edges of the plywood using 1/4-inch staples. The result was a fully-covered, flexible, wide-surface, 80-grit fairing board that made quick work of the edges and flat spots left over from planing. Of course, that's not to say it was easy work. The sanding process will have you working up quite a sweat in a matter of minutes. I put up with it for about 30 minutes of intense sanding, but then, once I was satisfied the hull was already close to fair, I plugged in the ROS and put on an 80-grit sanding disc.

Compared to the fairing board, the ROS is a dream-come-true. Just make sure you don't get carried away with it. Because the ROS sands so much faster and covers far less surface area than the fairing board, you have to be careful not to "linger" too long in any one place. If you do, you may end up with dips and other irregularities in your hull instead of a fair surface. In other words, keep the ROS moving. Work it back and forth in long, even strokes as if it were another fairing board. When sanding any of the more distinct curves of the hull, sweep the ROS vertically up and down the curve, tracing the contours carefully with gentle pressure. This should produce a nice, even curvature and minimize the likelihood that your "rounded" chines will suddenly go flat. Even so, stop the ROS often and run your hands back and forth over the wood to feel for high and low spots. Your sense of touch is probably the most accurate tool for determining whether your hull is fair or not, so trust your fingers.

After about 45 minutes of work with the ROS, I switched to a 120-grit disc and carefully went back over the hull to eliminate the 80-grit sanding scratches. By now, the beauty of the wood was really starting to show. Despite all the hard work, it's really a thrill to watch the finished shape of the hull take form. Unfortunately, the sander also seems to open up a few more gaps between strips. I might have been dismayed by this, but a trip to the hardware store and a little experimentation soon taught me that almost any gap can be filled to near-invisibility with a carefully color-matched wood-filler.

A close-up of the centerline after being filled with wood-filler.

Some builders use wood putty instead of filler, but filler is probably better since it dries harder and stronger. In truth, either one will work, so my advice is to buy whatever you can find that best matches the color of your hull, regardless of whether it is filler or putty. When color matching, keep in mind that the wood in your hull will darken when it is wetted out and fiberglassed. Your best bet is to take a sample strip of wood to the hardware store with you and wet it with water or saliva (to approximate its wetted-out color) before you match it to color samples of the various fillers and putties. Since my hull will be very dark when it is wetted out, I bought a small can of dark, walnut-colored wood-filler. From the color sample chart, I actually expected it to be a bit darker than the cedar in my hull, but after sanding, it appeared much lighter than the chart had indicated. Regardless, the color match was very close so I was extremely pleased. In fact, I had only planned to use it for filling the conspicuous gaps along the centerline of the hull, but once I saw how well it made the gaps disappear, I used it everywhere—in every perceptible crack and crevice of the boat. It took a little time and a lot of patience (I even went back to the store to buy another little can), but the pay-off was worth it. The hull strips look so much tighter and smoother now. Without looking extremely close, it's virtually impossible to tell where the filler was used.

For the final run of sanding, I wet down the entire hull with water to help raise the grain of the wood. Then, after the wood dried, I sanded over the entire hull one last time with 120-grit sandpaper to eliminate the wood "fuzz" raised by the water. The result was a very, very smooth surface. I used a little more wood-filler to fill the final few gaps that I could see in the boat and then gave the stems a little more attention to shape them to a nice, smooth, consistent shape. At long last, the entire hull was ready to be sealed with epoxy and then fiberglassed!


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