The Day the Carbon Kevlar, Fibreglass Cloth and Epoxy Came Together

One would expect that when you build a wooden strip-planked kayak, it is made of wood.  Well, yes—that is only partially correct.  The ¼-inch thin strips of wood form the core of the kayak.  They are like the eggshell of a chicken egg.  Unfortunately, in its natural state, the type of wood we use in building these kayaks is soft and quite permeable.  They will float in their natural state, but you have to coat them with a material that keeps the water out—not only of the kayak itself but the wood it is made from.

The early Inuit kayaks were made from whale bones and sealskin, which is naturally waterproof.  As the whales and seals left, kayaks turned to wood.  Initially they were covered in tar and pitch, or even special oils.  Then along came petrochemicals, and we get polyester and vinylester resins, and now the more sophisticated epoxy resins.  Epoxy resin is a chemical process rather than an evaporative process, so mix it correctly and it will harden.  Heat only makes it more viscous.

Epoxy station

Now, having said that, resins have very little surface strength and bend easily.  To address this in constructing a kayak, one adds a closely woven cloth (sometimes chopped mat) to the surface of the wood.  This is then saturated with the epoxy resin and you get a very strong structure.  Add a more sophisticated material like carbon fibre cloth and it gets better—but wait, there's more.  Add kevlar woven into the carbon fabric and one, after adding resin, gets a very strong structure.  You can jump on it and the ¼-inch wooden strips will not bend or break, so if you jump into the cockpit it will only flex.

Carbon fibre Kevlar cloth

Carbon fibre kevlar cloth is almost $100 a square metre, so for my kayak I have to use it very sparingly—in fact, only in the cockpit area.  The professionals use vacuum bags to draw the resin onto and through the cloth and force the cloth directly onto the wood substrate.  Well, again those bags are expensive and the vacuum pump well outside my budget.  The result is applying the resin by brush and squeegee.  It is a delicate process to get just enough resin to wet out the cloth and also to ensure no air bubbles are formed between the cloth and wood.

All of this is great in theory, and one can practise to perfect your technique, but the major variable in the whole exercise is the ambient temperature, which has to be above 11 degrees Celsius.  Here in Canberra, ACT, Australia, we have—unlike those in Europe—been experiencing the longest cold stretch of night and day temperatures since reliable records have been kept.  So each day I check the weather report and the temperature increase during the day to schedule the two epoxy days.

Weather forecast

The day arrived, but the weather forecast started badly: it is only -6.3°C but a high of 14°C.  OK, that looked positive, so let's get started.  I covered the side of the carport with a large blue sheet of plastic tarpaulin to try to keep the heat in and the wind out.  Then set the diesel space heater to high as I watched the temperature in the work area rise above 11°C and on towards 20°C.  The epoxy resin and hardener were placed over a large saucepan of slow boiling water to keep them warm.  The cloth and kevlar had been sitting in the interior of the hull and deck all night, so there were no wrinkles.

Go—bring the wood, fibreglass cloth, carbon fibre kevlar and resin together in the right proportions.  One has to work methodically and exactly, ensuring the mixture is always perfect.  Never reuse a mixing cup, and try to disperse the resin before the chemical reaction in the cup starts to heat up.  A fine balancing act.

Epoxy resin on the cloth

Both the hull and deck went according to plan, and I was able to complete the hull on day one and deck on day two before the temperature at five in the afternoon took a nosedive below zero.  Both sets got tacky within two hours, so by lunchtime I was able to apply the first fill coat and by 5 PM the second fill coat.  I trimmed the excess cloth soon after dinner, but the carbon fibre kevlar would not cut with either scissors or box cutter.  The fill layers are smooth but not too thick.  By morning most of the resin was hard, and by the expected 15 hours was quite hard.

Cloth completely wetted out

That was a big job completed.  The major lesson learnt is don't start a fibreglass project in the middle of the Canberra winter unless you have a good heated room—why not my dining room?

The cockpit coaming and internals is the next big stage of the kayak project.

Sanding the Interior of the Kayak

"Why sand the interior of the kayak? No one can see it," a friend asked.  I will sand it perfectly smooth because I will always see it.  Once seen, never forgotten.  And so started the long, arduous and very dusty task of cleaning the hot glue spots and excess wood glue from the interior of the kayak and sanding it smooth, ready for the fibreglass cloth and carbon kevlar to be added to the interior.

Hot glue spots on interior

I had finished epoxying the outside of both the hull and the deck, and that had turned out well, so I made some forms for the two parts to sit in so that I could access the interior.  They sat upturned next to each other.

Hot glue spots cannot be sanded because they melt and gum up your sandpaper, so they have to be scraped off the wood where they have adhered to the interior.  I have a number of wood scrapers that I had previously used.  There is a secret method of sharpening a scraper blade.  It has to be sharp—not like a block plane—because you use the scraper not to cut shavings off a piece of wood but to scrape the shavings off.  Consequently, one sharpens the scraper blade and then runs a steel over the sharp edge and turns the edge into a hook or burr, which forms the scraping blade.  This will ensure the scraper produces fine shavings that are of uniform thickness.  A true art learnt over many years.

Scrapers ready

One starts with the obvious spots with some easy results, but then as you get closer and closer to the final output, you see how the wood glue and hot glue has settled into the cracks.  Now, strip planking a kayak seems like an easy task: lay the strips on the forms and make sure they are glued to their neighbour.  But that is not so simple because the forms are round from the part line to the keelson, and what's more, from bow outwards to the widest part and then it narrows to the stern.

I had addressed this challenge on the outside of the hull when I came to sand that surface prior to applying the fibreglass cloth.  The difference on the interior is that the strip joins may look great on the important outside, but they may not exactly match on the inside.  Furthermore, one is dealing with a concave surface into which a flat scraper or sandpaper block will not fit.  The solution is to use one of the four scrapers I had sharpened.  The large flat scraper was good for the initial glue removal and then to scrape the raised strips down to the same thickness as their neighbour.  The smaller scraper was great on the curved sides, and what's more, with their handle I was able to get a good clean shaving from the Myrtle wood.

Using the small scraper

Next comes the dirty part: sanding the surface smooth such that the fibreglass or carbon kevlar cloth will lie flat on the surface to be wet out by the epoxy.  I put on a beanie, full breathing mask and safety glasses, but still the wood dust seemed to get everywhere.  The only solution was short bursts and then retire to wash my face and head to get the dust out.

Sanding the interior

I could only continue these sessions in short bursts, so the whole operation of sanding the interior took about seven days for both deck and hull.  Once finished, I mixed up some epoxy and wood dust to make a filler and applied that along some of the open joins—again to be sanded smooth.

Filling some gaps

Now the weather again came into play, and I had to wait for some winter days that were not foggy and had a number of hours during the day that rose above 12 degrees Celsius.

Both units ready for cloth and epoxy

The fibreglass cloth and expensive carbon kevlar were waiting to be placed in the interior and wet out to add strength to the kayak and keep the wood from getting wet.

Working with Weather: Applying Epoxy in Winter Conditions

While sailing on Malua, I watch the weather forecast every morning and evening as they are produced by our local Bureau of Meteorology.  In addition, I look at Windy with their different forecast models from data around the world.  Using the wind data, I plan my route, departure time, and develop a sailing plan.  There is very little one can do to modify the prediction—only modify one's plans.

That is exactly what I had to do when planning to apply epoxy resin and fibreglass cloth to the hull and deck of the kayak.  I had finished the sanding, separated the two sections of the kayak, and placed them on trestles ready to apply the epoxy, only the weather forecasts for the next two weeks did not look good.  They showed rain, frost, and only moderately warm days. I resigned myself to a long delay in the construction, BUT...

Industrial space heater

My neighbour built a very large house with a 6-car garage at ground level next to us—thankfully while we were sailing in Europe.  I went to talk to him, and he volunteered to lend me his industrial diesel-powered space heater to heat my 2-car garage where I am building the kayak.

Plan B had just fallen into place.  I could modify at least the temperature and, to some extent, the humidity of the build environment.  It was then only a question of choosing days with adequate daytime temperature which I could increase to above 20°C and nights that did not drop below freezing.

Now, the Australian winter officially starts on 1 June, and the forecast indicated there would be three days thereafter that would have daytime temperatures of 17°C  and nights of 4°C to 5°C.

Time to swing into action and get everything ready for the epoxy day.

I placed the 200gm fibreglass cloth on the upturned hull and cut a skirt around the sides, then started to brush it smooth for the next day's wet-out.  It looked good.  That night, I took the two West System containers into the house and put them next to the house heater output ducts so they would warm to increase their viscosity.  I also got out a large cooking pot and my portable induction plate and put them ready with a grid to keep the containers out of a layer of water.  During the wetting-out, the containers would stand in the pot over boiling water to keep them hot.  I checked the dispensing pumps on the 105 Resin and 207 slow clear hardener and found the hardener pump did not always give the correct volume—keep that in mind.  Squeegees and rubber gloves were at the ready, plus a small high-density foam paint roller and tray.

Start of day foggy but no rain

The day dawned, and I checked the forecast. The temperature was just above 5°C but would reach a high of 17°C at about 2:00 in the afternoon, then drop at 7:00 towards 5°C.  Unfortunately, there was a thick fog that blanketed the area.

Temperature range

I started the industrial space heater and set it at the end of the carport.  It soon became obvious that the hot air was heating the immediate surroundings, but the sides of the carport being marginally open permitted cold air to replace the warm air as it rose.  Off to the stack of blue plastic tarpaulins I had used in the construction of Malua, and I started to hang them from the gutter beams right down to the floor on the open side of the carport.  One could immediately feel the temperature rise, although there were enough holes for the heater to struggle to get the environment above 22°C.

Start of day Heater in background Epoxy foreground

At 10:00, I started the first epoxy wet-out of the fibreglass cloth.  I built my first fibreglass surfboard in 1964 and have played with polyester and vinylester resins ever since, including building the hard dogger for Malua.  Furthermore, in the previous month I had assisted my friend Jim to epoxy his diagonal-planked freighter canoe, so the epoxy system was not new to me.

Wetting out cloth with squeegee

There are some golden rules to follow in using the epoxy system, namely: Keep the temperature above 10°C and the humidity low—no rain.  Measure the components exactly—preferably using the supplied pumps.  Mix the two components for at least one minute before applying.  Use a new mixing cup with every new batch.  Don't keep the volume of mixed material in the cup for longer than necessary—it gets hot.  Finally, use a good plastic squeegee or short-haired brush to apply the resin onto the cloth.

Go!  I started in the middle of the hull and worked towards the stern and bow with each new batch of resin.  Pour the cup over an appropriate area and work the squeegee and brush to wet-out the cloth.  It turns from white to clear transparent when it is correct.  Do this in small areas, making sure you don't leave an island of dry cloth or leave an excess of resin to form a teardrop.

I used 20 pumps of resin for the complete hull with the appropriate amount of hardener.  The next phase is to ensure that the cloth does not float on a bed of resin but adheres to the wood beneath.  The best way is to use the squeegee to move the excess away from the area.  Catch this excess from the squeegee in a cup with a slit in the side as you brush off the excess.  If you press too hard, the cloth turns white, so be careful and never reuse the excess resin because it is full of bubbles.  In this case, work from keelson down the sides of the kayak.  You will start to see the grain of the wood and also the texture of the cloth.  Do not leave too much resin at this critical stage.

Wetting out underway

This is the critical environmental stage of the chemical process.  Unlike polyester resin where the styrene evaporates, the epoxy is a pure chemical process.  Applying heat will only make the resin more viscous and may increase the set time a little if the resin is concentrated.

With the space heater going full bore, I was able to keep the temperature around 20°C and the humidity low.  Now, wait for the process to occur.

After about 2 hours, you test the surface to see if it is ready for the first fill coat.  The resin should be touch dry, and if one applies a ball of cotton wool, the strands will just stick to the surface.  OK, we can start the next step.

The fill coat is a coat of clear epoxy resin used to fill in the texture of the cloth to give it a smooth surface for the final product.  There are many ways to apply the fill coat—from brush and squeegee to a paint roller. Depending on the application, area, and how many coats you want, you choose the correct tool.  In my case, I wanted to get a number of thin coats of resin so that they adhered to the layer below and the thickness was uniform across all sections. It had the consequence that I could only apply one coat every two or so hours and needed to keep the carport around 20°C, knowing that the outside temperature would start to drop significantly at about 4:00 in the afternoon.

I mixed the resin and hardener in a new cup every time and then transferred it to the paint tray and continued to use the same roller until the total hull was coated.  This works well.  I started to mix the resin for the obligatory one minute and noticed that I was introducing air bubbles to the mixture.  Tipping it into the tray and using it immediately transferred the bubbles onto the kayak surface—not good.

First fill coat

To ensure all bubbles were removed, I used my best long-haired paint brush to tip the still-wet surface free of bubbles and to ensure it was level.  This takes skill and practice to get it right but is essential.  As stated above, heat increases the viscosity of the resin, so I got out the heat gun and moved over the surface of the kayak with gun in one hand and brush in the other to smooth the surface and for any trapped air bubbles to come to the surface.  One can apply quite a lot of heat to a spot without any detrimental effect, except the resin runs.

I applied three fill coats after the wet-out and in most areas obtained a smooth surface with no cloth texture showing.  I was limited by the outside temperature, or I would have applied a fifth coat on the sides to completely fill the cloth.  That can come later.

The heater ran for two hours after the last roller and brush stroke.

The next morning, I started the heater soon after dawn and ran it for three hours, but it was not necessary as the resin was hard and smooth all over the kayak.  This day had a very poor temperature forecast, so I decided to wait a day and start the deck the next day, which had an improved temperature range.

The deck, which I had set up on a second strongback, went according to plan.  Its surface area is less than the hull, and therefore I used less resin—34 pumps to 43 pumps, excluding hardener, which is in a ratio of 1:3 (105:207).

Hull and deck epoxy with fill coats

The weather cooperated and the space heater assisted, and everything went to plan.  It dried during the night to a smooth surface with only a few imperfections such as dust and small bubbles.  Those will sand out after I clean and epoxy the insides of the kayak.  This stage is full of dust and is not enjoyable.

Final Strip and Parting

The recommended approach to building a kayak is to start with the lower hull and complete that first.  The advantage of this method is that you'll build your skill level, iron out any difficulties, and see how the process works.  Having learnt from your mistakes—or rather, having built some experience—you can then move on to the deck of the kayak.  That's the area you'll view all the time, so naturally, you want it to be perfect.

In my case, this was a very wise move.  Not only did I reject the use of cove and bead strips, but I also perfected the sequence of adding strips so I could add more strips in a day.

Turning the Kayak

To turn a kayak with an internal strongback, one has to remember to knock the hot glue spots away from the forms and strips before you start to cover the deck.  At some point, you will have created a complete shell and you need to remove the strongback and the forms.  The first strip on the deck after turning the kayak to start the deck is not glued to the hull strip, and therefore when you have finished the deck, you can part the two pieces and remove the internal structure.

On the Micro Bootlegger Solo, the inner stem and stern are, during the build process, still in one piece, and the strips are glued to this piece as they terminate at each end.  So to part the kayak, you knock the forms away from the strips on the hull and, using the thinnest blade saw, cut the inner stem and stern into two pieces—hull and deck.

Modifying the Design

Having loosened the forms, they have to be returned to their correct locations and made rigid to take the deck strips in the correct shape.  I had decided early on in the build process that I didn't like Nick Schade's design with the very hard chines between the side deck and the curve of the aft and fore deck, so I had rounded the forms into a shape I thought looked more natural and smooth.

With the section around the cockpit especially—as I had also decided to markedly reduce the size of the solo cockpit—the modifications were compounded, and the natural flow of the foredeck meeting the cockpit side did require some ongoing building of the forms to take the strips.  This is very noticeable along the aft deck.  I had also decided that the aft deck, while having round sides, would look good being quite flat.  It's a feature of this design and has some advantages I'll reveal later in the build.

The Aft Deck Challenge

The aft deck didn't quite go according to plan because as I tried to get the strips to conform to the increased curve from side to deck with it being flat, the side strips started to part from the forms.  I had to use a strap around the whole kayak with wedges to get them back into shape and add some hot glue blobs to keep them together.  A further cause of this issue was that the tape I had used to attach to the forms started to come away from the form along with the hot glue drops.  This wouldn't have occurred if I had used staples.

The result came out OK, but it had me worried for a few hours. I  overcame the rounded chines and then set about filling the flat deck between them—from the central Marbo dark highlight strip out to the side deck.  As you progress outwards parallel to the central strip, the added strips have a more acute angle towards the stern. Finally, you're adding short, narrow-ended strips until you've covered the aft deck right up to the back end of the cockpit.

Take a break and review the process.

The Foredeck

The final stretch of the strip build process is the foredeck.  A beautiful feature of this design is the straight up-and-down bow, the big bold fore section of the kayak, and the round shape of the deck as it expands from the sharp bow out and up to the cockpit. It has all the attributes of a surf ski or seagoing surf kayak but with a sit-in cockpit.

With the high side of the hull completed—these strips extend from bow to stern—it was only a question of stripping in the foredeck.  I had selected a few planks with interesting grain and stripped them, setting them aside for the foredeck.  Again, the ends of the strips, which are set parallel to the highlight strip down the middle, get shorter and sharper as you fill the space.

With every strip you select, you match it to its place, lay it in position, then mark the cut to fit the sharp end.  I use a Fein vibrating saw with a circular blade and very fine teeth.  Having marked the strip, I cut it.  If I concentrate and have a steady hand, I can almost cut a perfect fit for the end of the strip.  It's only a case of a few strokes with the small hand plane or 80-grit sandpaper and the strip fits.  Remember, near enough is not good enough.  So test, test, and then retest until the strip fits all along its entire length.  Apply glue to the correct side and then tap the strip into place after a quick application of hot glue in the correct places on the forms.  Use masking tape to hold against the previous strip and clamps to ensure they stay down and alongside.

I initially tried to use a wooden wedge between the new strip and the outer side strip and found, to my dismay, that a strip end—while dry-fitted perfectly—had gaps at the end when glue was applied.  Only after two attempts did I realise my error: without the wedge, the gap between strip and deck was normal, but with a wedge, it pushed the deck strip away from the centre line and increased the gap of the previously fitted sharp-end strip. Silly me.

The Final Whisky Strip

I finally came to fit the final strip in the kayak—a short strip on the starboard foredeck.  Measured, fitted, tested, retested, dry-fitted, glued, and finally fitted the last strip.

At this point, the shipwrights of old, mostly from North America, would celebrate with a nip of their local brew.  But having many ancestors born and raised in Scotland, I went to the cupboard and got out an Edinburgh Crystal Thistle Whisky Glass Tumbler and toasted the final strip planked on my kayak.

Parting the Hull and Deck

Now came the parting of the two pieces to epoxy the hull and deck and to remove the strongback and work on the interior.

I cut the bow and stern inner pieces and used soft, wide wood wedges to drive the two-part strips apart and separate the hull from the deck.  It started to come away from the hull where I had previously separated the forms from the strips, but the end pieces remained stuck.  A few more wedges and a gentle lift of the bow, and the two pieces came away in my hands.  Success.

I turned the deck over on a set of trestles and removed the form distance separators, then firmly tapped the forms away from the end towards a wider part of the kayak.  Thankfully, the forms came away and I was able to lift the forms and strongback out of the kayak.

In parting the hull, a few strips sprang where the glue had taken to the forms and not been cleanly released.  It was a quick and easy task to apply glue to the gap, push the strip back into place, and apply some masking tape—or in one case, a 10kg piece of lead—to keep it down and in place.

Preparing for the Next Phase

I had kept the excess length of square aluminium tube I'd secured for the strongback and used it to make a second strongback.  I used every second form on the hull section and created two strongbacks for hull and deck.  The kayak now rests on the forms and hopefully won't lose its shape during the final sanding and application of glass cloth and epoxy fibreglass.

I am in Canberra, Australia, where we are entering winter—officially on 1st June—and we have during our winter many nights falling below freezing, but then the day temperature rises to about 15 to 18 degrees C (65°F).

The question now is: will I have a day temperatures long enough to apply the epoxy, and how long will I have to wait for the temperature to rise?

Bottom finished, now to strip the deck

Most boat builders, particularly those building strip canoes, reach a point when they add the last strip of wood in the hull of the vessel.  The North Americans all seem to reach for the "whisky" bottle as they place the last piece into the hull.  Of course, it's not actual Scottish whisky but some look-alike.  With salt in my veins, I reach for the bottle of rum – Australian Bundaberg – and toast the last plank.  BUT with a kayak, one is not finished at this point because you still have to strip plank the deck – both fore and aft deck around the cockpit. So no rum at this stage.  It can age for a few more weeks.

The turning of the hull, especially with an internal strongback, is a major operation – not only because of the weight but also because one needs to have a cradle to place the hull on so you can work on the deck.  I had cut two cradles from the shape of the forms before I put them on the strongback and covered them with foam, so the turning was an easy operation.

While cutting and machining the strips, I had selected a few for the side deck and for the fore and aft deck, so it was just a question of taking them down from the rack in the roof and selecting the strips for the side up from the part line.

The part line is the widest part of the kayak, and the hull strip is not glued to the adjacent deck strip.  This way, when the deck is finished, one can just lift the hull from the deck and the two parts can be worked on individually.  I used the hot glue gun method rather than the staple method to keep the strips attached to the forms and to take on the shape of the hull.  Before starting on the deck, I removed the middle form wedge and knocked the forms off the strips where they were attached to the wooden strips.  You start at the middle and knock the form toward the wide part of the kayak.  It sounds scary that the strips will spring off the kayak and jump out of shape from the forms, but the hot glue drops come away from the masking tape on the forms surprisingly easily.  Work your way from the centre towards the bow and then work your way to the stern.  With all the forms loose, it's time to put the spacers back in place between the forms and to insert the wedges in the middle space – in my case between the two form 8s.

Now the important part: the strip which runs from bow to stern along the part line of the hull was the next task.  Not too difficult.  Do both sides and hot glue onto the forms, but glue to the stem and stern piece.  The second strip is the important one because it is glued to the first and hot glued to the form plus real glue to stem and stern.

As one strips up the side of the deck, the curve on the solo microbootlegger gets greater and greater.  I think Nick Schade originally designed this vessel to be 18 feet long and then reduced the distance between the forms from 12 inches to 10 inches to reduce the length of the kayak.  The twists and turns on this hull's strips are difficult to follow.  I needed to use the heat gun at the bow and stern to get the strips to twist onto the end pieces.  It required lots of clamps and multiple sessions with the glue gun.

I had decided early on in the build that I did not like the hard chines as the hull came up to the deck, so I smoothed the hard corner to a more rounded shape.  This looked good on the forms but added a lot more work in bevelling the edges of the strips to match each other around the curves.  This is not a requirement in cove and bead strip planking.  The rabbet plane I had purchased at an online auction at the start of the year – well sharpened and correctly adjusted – made the task easy but long-winded.  You start at the lower – fixed strip and plane off the edge at the angle of the form to match where the next strip will go.  Then continue planing around a form till each wood shave is full width and at the right angle.  Back and forth between forms with a test strip to check the gap between the two adjacent strips.  Next, move to the next form and continue the correct angle.  On a section of the hull that is reasonably straight, like in the middle, that sounds easy, but wait till you get to the complex curves near the bow and stern when you have the strip curving towards the ends, twisting from vertical to almost horizontal, and you have a real challenge.  Remember, in this project, "near enough is not good enough." Each strip has to match its neighbour without the slightest gap.

At some point, one moves from strip planking the sides of the kayak to covering the deck.  In this design, that is the chine, but as stated above, I had rounded the forms to try to eliminate this transition point as a smooth curve.  I reached that point but noticed as I progressed, the deck part line strips were moving away from the hull part line strip.  This, I understand, is not an unusual occurrence because the hot glue spots of the hull no longer hold these strips to the form.  The solution is quite simple: hot glue a short strip to the top hull strip at right angles to the strip, then glue a further short strip to the bottom strip of the deck. The two match each other but are attached to opposing strips and thus work against each other to keep the two non-glued strips together.

The aft deck seemed like the next step to tackle.  It is relatively flat, and I had selected some good-looking strips to make a feature of this section.  There are many designs that one can use in planking the deck of these kayaks.  Because I have a very plain, ordinary wood – Myrtle – there are no intricate designs I could use, but the layout of the planks has four basic designs.   I chose a highlight central strip and then arranged the planks to be laid parallel to this line as they move out to the side of the side deck. There are some intricate joins as one moves from the stern forward with the strips getting shorter and shorter, but no difficult curves to contend with.

The aft deck planking had to wait as I took a break to return to the coast to do some maintenance on the house.  It was a good break away from construction. I took the time to design the cockpit.  The micro Bootlegger has a large cockpit with wide sides which I did not like.  There is nothing to place your knees against, and the size would make the kayak vulnerable to being swamped.  I took another cockpit design and drew it on a large sheet of paper, but that design was too small.  So I measured the size of my backside and the distance to my knees and the comfortable width, and free-handed the new cockpit design.  On paper, it looked good and a reasonable size. 

Stripping the aft port deck

Next will come the cockpit recess, which is the transition from the deck to the cockpit coaming.  There are many ways to do this, so off to watch a few YouTube videos and Facebook posts to get some ideas. That will have to wait till I finish stripping the deck, although I have now decided the size of the cockpit hole.

More stripping and covering up

Now with the correct router bit and a new table for the router, I was able to rectify the spoiled strips from the broken bit.   I selected three strips and cut the broken coves off them, making them narrower, and then ran them and the equivalent opposite side strips through the new table router.  The chips flew and it sounded great.  Next, the remaining strips. I had decided that I would not use this strip and cove method on the six light coloured strips right next to the keelson, so they remained in the store.

Cutting the cove with new Router bit and table

Off again with hot glue gun and strips along the outside edge of the bottom. I was getting the hang of this form of construction but decided to only do three strips a day so the glue could dry. I turned my attention to making a two-bladed paddle from the wood stored in my timber pile. That is a separate post here.

An opportunity to sail across Bass Strait with a good friend Andrew on Eye Candy came up, so I jumped at that opportunity. It was a dream crossing which I have documented here. Three days to cross and less than 3 hours to fly home. Back to the kayak.https://malua.blogspot.com/2025/03/was-that-dream-or-even-maybe-short.html

While I only did three or four strips a day, the sides of the bottom of the hull soon closed up and I was progressing towards the centre line. Each strip gets shorter as one moves towards the centre, and at some point the curve or outward bend from the ends is quite extreme, so I would dry fit the strip and leave it in position a few hours before proceeding. The Titebond Regular has a pot time of only about 6 minutes, so one has to work fast to secure each strip in position and against its outside neighbour. Rough surface green masking tape is the answer. One pulls the strip outwards, places a small drop of hot glue on the frame, pulls outwards and down for a minute or so, and secures the strip in position with the green tape. I use small clamps to ensure each strip matches horizontally with its neighbour.

Planking the second side

OK, one side completed. Now draw a perfectly straight centre line from bow to stern and then, if using the traditional method, use a Japanese pull saw to cut the excess of the one side strips. I used my traditional Fein vibrating saw I have had for years and was able to cut a perfect straight line using the new round blade from Fein. Adapt with technology.

Cutting the straight Fein line

Now the inside section of the bottom of the hull. I thought I knew what I was doing at this stage, but the initial strips had to be reglued and adjusted before proceeding. Then as one strip at a time was added, I climbed the sides of the hull until I came to the sharp curvature of the hull where I thought the cove and bead would make it easy. Not so. In fact, I found the use of this material easy to put a strip in place, but the mechanics of the curve meant that the adjacent strip exposed the gap, and with the very thin lip of the cove, it tended to either break away or, when sanded, expose the gap between strips. Not happy – in fact I will not use this method for the rest of the kayak.

Again, the strips get shorter, but this time rather than leave them to overlap the centre line, one has to cut them at both ends to fit into the narrowing space. The method used is: cut one side, plane it to fit the sharp pointed space, remembering the strip does not run parallel to the centre line but bends outwards. Fit the piece, then take the strip and place it in its position. It wants to twist and jump out, so a few clamps and plywood U-locks are used. Now confront the other end and mark the section to be cut off. Saw and plane to fit, then snap the strip into place to see that all is well.

Strips get shorter and shorter

Remove strip. Set on its side and apply a thin bead of glue to the correct edge (Don't ask why I highlight this) and then position the strip in place at one end and fit. Move away from this sharp end and secure strip to its in situ neighbour with green tape and a few small clamps, then snap the other end in place. Return to the strip with masking tape and hot gun glue and secure the new strip tight against its neighbour and down against the frame. Move quickly and diligently back to the first sharp point. Check that each strip is aligned against the neighbour and down on the frame. A heat gun can assist if it has popped up as you moved on. With a wet cloth, wipe up the excess glue.

Sit back and admire your work, knowing that in my case I am only about 1/3 the number of strips secured prior to the last. When will I reach the final whisky strip? I need it!

Ready for the Whisky strip

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

Most of the strip-planked 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 were not 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 using this method. 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 risen 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.  It arrived and I unpacked it but there had been a slip between cup and lip from the technical person who selected the bit and the "sales" person at reception so she sent the incorrect bit.

Back on the phone to get the right bit.  Technical person now states they dont have the correct bit in stock so will have to have none made for me next week just send email.  OK email off immediately.  Wait wait.

Why has it not come.  "You never sent the email." I can only have it machined on Tuesday next week.  "OK go ahead"  Wait Wait.

I received the tracking order on Tuesday at 4:30 pm.  Follow the Australia Post.  Next day at about 10:00 am I get a knock on the door.  Your express parcel from Melbourne has arrived.  Great!

YES, it is the right bit and it fits the router and it cut a perfect cove on my strips.  Now back to building the kayak.