Making a cove and bead strip with questionable quality route bits.

Most of the strip-blanked kayaks made in North America use cove and bead strips, either purchased ready-made or cut using professional machines. The cove and bead profile is an edge treatment that consists of a concave hollow shape (cove) and a convex rounded shape (bead). You need one or two router bits to cut the opposite edges of the strip. These are also known as canoe bits, used to make interlocking sealed edge joints.

Keen to use this method in my kayak, I'd selected two router bits from a Chinese manufacturer advertised on AliExpress. I paid about a fifth of the price of the equivalent American product but had to wait two weeks for delivery. When they arrived, I quickly noticed the shank wasn't the advertised ¼ inch, so they wouldn't fit into my router without a ¼ inch collar and some super glue. After a few test runs, I cut the short strips for a test panel. All looked good.

While building the second test panel, I found it easy to cover the rounded hull. However, it had a disadvantage: the edges of the cove – or cave shape – are quite thin on the strips I'm using. On one strip, the edge had broken away, leaving an open join.

The skill lies in adjusting the router so the edges of the cove are thin but not so delicate that they get damaged. To test, I use a black marker on the edge of the strip and pass it against the router bit, adjusting it so that two thin black lines appear at the extreme of the cove indentation.

Having proved the concept on the test panel, it was time to cut the cove and bead on the strips above the highlight strip at the acute curve of the chine. I'd carefully selected strips for colour and length, numbered them on port and starboard sides, and set up the table router to take the long strips. I was ready to cut the 20 or so strips for that part of the hull's bottom.

Cove and bead router bits

With the Chinese ¼ inch shaft in the router and after many test strips, I'd adjusted everything to run smoothly. The first strip cut was smooth as silk – a perfect bead, round at the edges and central. The second strip entered the machine, and the noise and flying wood chips were as expected. But then the number of chips coming off the blade changed. I immediately stopped to investigate. The two tungsten blades looked fine, so I suspected the blade had moved and made some adjustments. But the cut was all over the place.

As I watched the blade slow down after switching off the machine, I immediately noticed the ¼ inch shaft was bent. "Cheap Chinese quality," I muttered – or words to that effect!

I turned to an Australian supplier, ordering via Express Post from Melbourne to Canberra for a replacement bit. This time, I chose a ½ inch shank – something that wouldn't bend, though it cost five times as much. I had to wait and, of course, come up with a solution for my spoiled strips. That was easy: I'd cut them narrower, which would also make rounding the chine easier and give a much smoother finish. I followed the Australian Post tracking notifications almost every hour while waiting for the new bit to arrive.

Three days later, the bead router bit was delivered. I immediately set it into the table router and passed the strips through to cut the round-edged bead.

Table router with strips in background

Next came the cove on the opposite side of the strips. I have two routers – one set in a table that I've used extensively in the fit-out of Malua. It works like a dream. I also have a sophisticated Elu hand router with all the table and other attachments that I use for finer work, but it's a hand router. I needed to put that in a table to pass the long strips through and minutely adjust the depth and location of the cove bead.

I picked up a wooden bar stool from the recycle centre at the dump for $5, which became the basis for my table router. I then used Malua's old cockpit table – which I'd already replaced – as the basis for an adjustable table. After a few hours and some extra timber to extend the legs, I had my second table router complete with a fence and featherboards.

Basic table router from bar stool

After some adjustments and test runs, I was satisfied with the setup to pass the diminishing number of strips through the router to cut the cove. The first strip went through like a dream, but the second stuck halfway as the chip count dropped to almost nothing. Again, the cheap Chinese router bit had let me down – it wouldn't hold in the chuck of the router but rose up, destroying the strip. Expletives followed, predictably. Back on the phone to Melbourne, I ordered a cove router bit with express delivery.

Strips ready for bottom of hull and to be routed

Wait, wait.

More stripping and a highlight strip.

I had now reached the waterline of the hull and I wanted to add a highlighted strip. What wood should I use?  The Myrtle is quite light and tends to bleach to a mellow-yellow after a few months out in the sun, so a light highlighter strip was not an option.

Highlighter strip finished

I searched my lumber stack for a dark-coloured piece of timber which I could cut into a ¼ by ¼ inch strip to highlight the waterline, but found nothing.  Then began the search of the local timber yards, which are now oriented toward the building industry and not cabinet making or woodworking.  I visited three to search the stacks.  Most of their dark wood was hardwood and not very dark – like spotted gum, Jarrah, or Ash. Most of the planks were also quite short.

Someone suggested AJAA Timbers at Queanbeyan.  I took off in the small Golf and spoke to the son of the owner who directed me to Alex.  It appeared he knew every piece of timber in their extensive yard, but we drew a blank in the main shed, so he sent me off to the distant shed to have a look.  It was full of timber poorly stacked and not quite what I was looking for, but I did find a few one-inch square battens of Merbau that were 7.5 meters long.  I selected two but decided to only take one to test.  I got it for a very reasonable price and then strapped it onto the roof of the Golf with long overhangs fore and aft.

I soon had the batten on the table saw and cut a few suitable-sized strips for the waterline.  They are not quite what I had in mind, but this South East Asian timber, which may have come from the Philippines, is orange-brown in colour but ages to a darker reddish-brown.  It has a tendency to stain if used as an outdoor decking timber, but that will not happen on the kayak.

I quickly prepared the lower strip for this square highlighter, but I made the Merbau strip too thin when I put them through the planer by turning the handle the wrong way!  Back to the yard and the distant shed to select the second-best piece.  Pay for it, tie it to the Golf, and again cut and thickness, but this time get the dimensions correct.  I had both sides glued in place soon after.  I hope it will darken over time.

Stern highlighter strip

Above the waterline strip of the hull, the kayak starts to curve over to the centre line of the keel, commonly known as the chine.  This corner is difficult to strip plank by bevelling the edge of the lower strip because the change in direction is quite large, so it is recommended to switch to a bead and cove system for stripping.  That is the next step in the stripping process, but what a saga.

Setting up the forms and aligning them ready to strip the kayak.

This step is critical to get right because the Myrtle strips are attached to the forms to create the shape of the final product.  If the forms are not aligned or not in the correct place, that will flow through to the final shape of the kayak.

Aligning the forms along part line

I had done the work on setting up the distance between the forms and ensuring that the forms are at right angles to the strongback by making spacers and ensuring they were correctly dimensioned and fitted tightly between each form.  I have documented this.  The forms and components are all well numbered and inscribed, so it was an easy job to push the forms onto the aluminium square tube strongback, slip the spacers between them, and then knock two wedges into the middle section to tighten the whole assembly.

Forms aligned

On this occasion, I had turned the kayak upside down so the bottom hull was uppermost and therefore the end pieces were inverted.  In addition, I attached some small wooden indicators using a hot glue gun at the part line (where one separates the hull from the deck during the build) so the first strip would rest upon them, and I could eye-ball these lines from bow to stern.  This made the alignment easy from bow to stern while sitting in my chair abeam of the kayak.

I checked the forms to see that they butt up against the strips as they touched the whole width of the form.  I had to do some adjustment to refine the angle created by the rotating sander in the previous operation.

The next step is to cover the edges of the forms with high-quality 3M packing tape so the hot glue used to attach the strip to the form sticks but is not permanently glued.  You remove the forms from the finished stripped kayak.  I am using this method rather than staples because I did not like the way staples leave holes in the finished strips for all to see.

The big day arrived, and the first two strips were ready to attach to the forms. Now, I had previously joined an extra 500 mm to the end of my selected strip with Titebond glue to get the final length of 4.2 meters.  As I picked up the long strip, the end fell off because the glue had not adequately set, and I was left with a short strip.

Back to the workbench.  So, I take the two selected pieces of wood, cut a scarf (45-degree cut) on the drop saw at the right angle as per the template. I created a template on the drop saw for the strips to fit into when I need to cut an accurate scarf.  I then move the two pieces to the glue template and place them in it, apply glue.  Now the crunch... Leave to dry for a few hours.

Joining the strips

After that setback, I attached the first strip at the part line using a hot glue gun between strip and form, working from the middle out.  The last station is the strip attached to the inner stem and stern, which requires actual Titebond glue.

That went very well and was easily done to the wooden indicator strips.  Next came the second strip on each side.  Because the side is vertical at this point, there is no requirement to make any adjustment to each strip. But more on that with the next strip.

The second, third and subsequent strips up the side of the kayak starts to curve inwards towards the centre-line along the hull bottom of the kayak, and thus it requires adjustment so it butts up against the strip below without leaving a gap on the outside edge.  Imagine two rectangles, one on top of the other. Then take the top one and lean it over to one side.  There is a gap on the outside while the inside is still touching the strip above.  To address this problem, one has to plane the inside edge of the lower strip to be at the precise angle of the rectangular strip above.

The second strip

Easy, take a block plane and run it along the strip.  Wrong, because firstly, the strip is now attached to the forms, and secondly, the angle varies as it changes from the upright of the bow and stern to the sides and corners of the hull as it turns to form the bottom of the kayak.  So what is the solution? 

Use a "rabbit" plane which was designed to solve this problem.  Knowing the issue when I set out on this journey, I bid and purchased a rabbit plane at an online auction in the USA and received a rusty second-hand Stanley Rabbit Plane No. 79.  I cleaned it up and sharpened both blades.  It turned out to be a gem and just the right tool to take a thin sliver of wood off the top of an attached strip at just the right angle.  What a delight to have the right tool for the job. BUT

Nick Schade of Guillemot Kayaks has designed a special Robo-Bevel based on a miniature shoulder plane made by Veritas.  The plane is ¼" wide, the same as the strips, and it fits into a plywood jig via two strong magnets.  To use it, one runs the plywood jig up against the forms as they curve into the centre-line, and the plane takes a thin wood shaving at the correct angle from the strip below.  It is such a neat solution and ensures that the angle matches the form and the strip above which leaves no gap between strips.  Not wanting to pay the $150 plus shipping, I took the idea and designed a local Australian knock-off of this jig using the Veritas plane.  It works wonders and makes the job of butting the strips an easy job.

Rabbit Plane and 1/4 plane jig

The third strip went on easily, and now I wanted to add a dark highlighted strip at the waterline.  That and the decision to move to a cove and bead stripping routine will come in the next saga.

Three strips in place

Cutting the strips for the Kayak

The forms are ready but I need the space to select the timber to use as the strips to plank the kayak and to cut the strips.  The strongback is disassembled and stored in the roof and the forms are neatly packed away.  Now to select the timber from my stack of Myrtle I used for the fit-out of Malua.  I found the two invoices for the timber purchased from AnaGote in Marrickville in Sydney. The first was for 2 inch and the second was for 1.5 inch of lengths about 3.5 to 3.8 meters long and planks 4 to 8 inch wide.  The total was $5,800 for a total of two cubic meters of timber.  I will sell the remaining 58 pieces back to them for a cut rate of only $8,000 at today's prices.

Strips cut

I selected 12 planks, 5 to 6 inches wide, all about 1 inch thick and longer than 3.5 m. The colour is uniform with two beautiful light brown which I will use on the lower hull and two planks with a very interesting grain for the aft deck.

Selected planks with remaining timber

Next was to put the planks through the thicknesser and get them down to the correct thickness or width for the strips.  I had adjusted the thicknesser and sharpened the blades.  All that was needed was a roll-on table for the feed and a receiving structure for the 3.8 meter long planks to come out the other end. Now that required I build a stand for the thicknesser so the feeds would be at the correct heights.  Back into the timber pile but not the Myrtle but the excess of the infrastructure for Malua like the steps up to the deck while building.  I selected two pieces and set about building a stand for the thicknesser.

Next step is to set up the table saw to cut the ¼ inch strips from the 22mm (1 inch) thick planks. I had used a saw blade my Dad used some years ago because it was sharp, thin and small but found it did not quite come up to the current performance of tungsten tipped saw blades so into my store and out with a 3 mm thick modern blade.  Fit it and the trailing divider and a new base and we were spinning ready to cut.  Because I have to cut about 160 strips (each about 3.8 m long) I used some feather boards (finger boards) I made from high-density polyethylene purchased from the local Reject Shop for less than $15.  I needed to cut them to size and then cut the fingers into the board. The finger touch the wood as it enters the saw blade area.  This worked well and stops the timber jumping up when fed into the saw and jumping back as one feeds the timber against the blade.

Table saw with feather boards

All ready to go.  Step one: take a selected board, put it through the thicknesser on one side, adjust the thickness and turn it over, then do the other side.  Continue until you have a plank that is 22 mm thick. Repeat for all 12 planks.

Step two: adjust table saw to cut a strip off the side of the plank at exactly 7 mm thick for the full length of the plank.  Repeat 10 to 15 times depending on the width of the plank.  Number each strip sequentially to keep the order and then bundle the plank strips in order. Repeat for 12 planks.

Next step is to thickness each strip to be exactly 6.25 mm thick which means take four strips from a plank bundle and put them through the thicknesser as the first pass. Turn them over and adjust the thickness to be exactly 6.25 mm thick.  Repeat for the rest of the strips in the plank.  Maintain the order and re-bundle the strips for each plank. Repeat for all 12 planks.

Strips selected for colour

Number each plank bundle and set out on the bench to select the length and colour for each location on the kayak.  Having done that, one needs to remember that the kayak is 4.2 m long and the majority of the strips needed for the bottom, sides and a bit of the deck will be 4.2 m long, so I will have to join the strips with an extra 0.5 m piece.  Another challenge.

Strips bundled

OK, all done which took a good two days work and I am ready to set up the strongback and the frames.