- Kayak model : F1
- Skin choice : Extremtextil
- Coating: gloss marine varnish from Soloplast Yachtcare
- Gunwales, stringers, …: spruce
- Ribs, Aft deck beam, Aft deck stringers, coaming: ash
- Color: acid dy
- Toggles: recycled HDPE
- Foam thigh brace: Decathlon yoga block
Hi, I am starting to build a F1. It will certainly take me a long time and I hope to succeed in filling in this student post. I hope also that my english is not too bad, sorry in advance for the mistakes.
I love woodworking and kayaking for a long time. I have started with whitewater kayaking and then I moved to canoeing at the birth of my children, it was the occasion to build a canoe in red cedar woodstrip with Ted Moores book and “La Cannoterie” plans.
Building a traditionnal greenland kayak is an old dream. However, all that I have read on this topic and the discussion I had with people using it showed me it was not an easy boat, in particular due to the small size of the coaming. The cape falkon work was then a great discovery. Thank you Brian and your team for what your are doing !!
My goal on this construction is to use the wood produced as close as possible from the workspace. I have the chance to live in a region with a lot of forest, mainly spruce, ash and oak. It is also the occasion to discover a part of woodworking I don’t know: greenwood carpentery.
The building started in the beginning of 2020 by the preparation of the workspace, the jigs and steambox.
On the top of the workspace is the 5 meters long spruce pieces of wood used for the 5/8″ thick cut list.
I have also received all the pieces of the kayak that might be difficult to find here. Thank you Brian for the shipping !
Curved deck beams
Due to the difficulty I have to find large piece of spruce with the good grain orientation and as I don’t have a table saw, I have chosen to paste together small pieces of wood. I have cut this composite board with a jig adapted to my plunge cut saw. The process is long but it finally works.
The spruce plys don’t bend as well as red cedar in the video. Maybe due to the large grain the plys are splitting. Steaming the ply is not working well, the plys are breaking and looks like crips out of the steaming box. A satisfying result is given after 30 min soaking in water. The plys are put in place in the curved deak beam laminating jig and let dry a couple of hours. The plys are then glued and put again on the jig. The result is not very uniform from one beam to the other but it seems to work. I hope it is OK.
II go on her with the idea to use the wood harvested in the near forest. I have cut an ash tree t and tried to split it on several long log quarters. The wood is reduced to the final shape with the axe, the drawknife and the plane. The trees in the mountain have not good straight fibers and lot of knots. Cutting the log to the dimension of the coaming and coaming lip is time consuming but the result seems promising.
The first trial of wood bending is not just bad but literally catastrophic. The coaming logs don’t show a bad bending, it just breaks. The soaking time was certainly too short (half a day) and the use of a kettle on a gas burner not optimal to produce enough vapor. Whatever, the observation is that building the coaming with this provenance of wood is going to be very complicated. And in the same time producing a single coaming log from an ash tree takes me a while…
I decided to adapt the bending strategy to my quality of wood. For the coaming, as the breakage occurs in the tightly curved parts of the log, I have reduced the thickness on these parts of the log. Once the coaming is bent, I complete with another part of wood, Gorilla bonded to have the good thickness.
The plan I have tried is as follows.
I have formed other coamings log from a thin ash tree, soaked the logs more time (two weeks) and use a vapor generator as recommended (6 minutes). The bending works well with this thickness reduction even if there are still small primer breakages on the lower part of the coaming.
On the following photo we see the upper part of the coaming with the two pieces of wood bonded together.
Unfortunately, I don’t think possible to use this strategy for the nailed coaming lip. I have tried another bending strategy that seems easier. Using notched wood is another way to reduce the thickness and by the way the stress on this thin but thick pieces of wood. A short geometric analysis and the measurement of the thickness of my Japanese saw line (~ 425 µm +/- 50 µm) give me the distance between the notches and the number of notches: 88 notches with 4mm distance on the upper part of the lip, 88 notches with 8mm distance on the lower part of the lip.
I use a simple jig to cut the notch at the good thickness. Bending is good and easy, I feel quieter. This solution is not ideal as it fragilizes the lip but I hope it will be ok with the help of the resin that should consolidate the notches.
The coaming is now finished I can start to work on the rest of the manufacturing process.
For the preparation of the ribs I have followed the same guideline as before: wood from the forest village, hand tools as much as possible.
I learn slowly how to form small pieces of wood from a log, trying to follow the grain of the wood. One video particularly inspires me about the work of a “merrandier” (https://www.youtube.com/watch?v=jsei4x9uXH4) I have not wood as good as in the video but I have tried to split my ash log as best as I can. For the building of the kayak I have renovated a shaving horse and learn to use drawknife. A great discovery !
Wood splitting appears to be quite complicate, maybe the trees of the mountain do not grow straight and come with some internal tension. I did not succeed in splitting and following the grain with just one or two wedges. To improve the result of splitting on small pieces of wood as the ribs, I had to build a series of small wedges. They help me to define a straight split along the log. For the big logs and the first split, I also built bigger wedges. I have improvised myself as a blacksmith, for such rudimentary tools, it was ok.
All this small wedges, reveal to be determinant and have allowed me to go through the process.
I split a log in four parts, then I adapt the form with an axe and the drawknife to split again each quarter log in smaller parts. No wood waste: the drawknife makes wonderful woodchips to start the wood stove.
When the form is OK I finish the work with a plane.
All this takes me a very long long time, more than one year for a result of about 30 ribs.
The ribs seems fine, not straight, but with a good flat grain and nearly good dimensions.
I cut the ribs to the required length for my two kayaks.
Then I prepare some ribs bundle to put in a water tank in the garden. Two bundle for the kayaks, one with spare ribs, and one for test ribs.
Preparing the gunwales
For the gunwales, I have thought about cutting and preparing the wood with hand tools but it was not relevant if I want to go one day on the water. The spruce wood was purchased in a sawmill, next to the village, cut in long boards of 5 m at the good thickness 5/8”, about 16 mm. I have bought about 8 boards cut from a tree and hoped I could find my way through the knots to produce 4 nice gunwales.
The village is in Chartreuse, few kilometers away from the place where is produced the famous green Chartreuse liqueur made by monks. It is a land of wood, with a lot of spruce used for carpentry. Here are some nice photos of spruce trunks taken in the village. On some sections, the knots make nice patterns.
But knots will soon have became a big preoccupation. Cutting the gunwales while avoiding the knots was just impossible. One logs seems nice with no knots but it was a trap. It shows me my poor knowledge of the wood.
The board on the right as no knots visible. But in fact, they extend laterally, in the core of the board. I have cut two gunwales and prepare them as required with all the tenons. With some knots appearing on the boarder of the gunwales, I should have paid more attention… At the very end of the process, when I have put the gunwales in place with the form and the straps, “patatra”. One of the gunwales breaks. Better in the workshop than in the water…
It brings me to a question for Brian (1) Is there a stress test we can do at the beginning to test the resistance of the gunwales? Could it be sufficient to put them in place, with the form and some vertical tension?
I have continued the process and produced two new gunwales as best as I can. At a location, one knot was too weak; I replaced it with a piece of wood.
The result is not as strong as it could be with a nice, straight grain, red cedar log. I keep this in mind. These kayaks are not designed to make long trips in stormy water. I hope it will be fine the first day on the water.
Preparing the deck and the stringer
If some knots seems to me acceptable on the long gunwales. The option was not possible for the deck and the stringers. Each knots was investigated and suppressed with the use of scarf joint. I have followed the general recommendation with a scarf length more than eight times the log thickness.
I cut the scarf with the plunge cut saw and bonded them with gorilla glue. For some issues power tools are helpful!
Bending the ribs
The crucial moment came this summer .
After two weeks soaked in water, the workshop was ready to welcome the ribs. The steambox was in place, as hot as it can be. It was early in the morning. Ready for the D-day.
When I put the ribs on the workbench, I realized that the wood has darken in the water. Reading the number of the ribs for its location was very difficult. Small moment of loneliness…
If you use a water tank outside, one advice is to write big number on each side of the ribs.
After a careful analysis, I recovered the ribs location and the bending process started. I have use a steaming duration of 3 min for these ash ribs.
The result was not so bad. I succeeded in locating all the ribs with “just” six ribs broken. These ribs was taken from the ribs prepared for the second kayak. It was evident that it was impossible for me to make both kayaks the same day.
I will have to prepare more ribs in the future for another D-day.
The lashing of the keel and the stringer was OK. At the end of the process, I had to remove the lashing on part of the keel. It was loosening tension and I started again the lashing. I was worried about this but I’ve seen a video of Brian telling it could occur.
I appreciated this part of the process. It is hard to believe that such a thin ligament could be so strong, particularly for the stringers that show a lot of tension.
Some knots are visible in the location of the coaming, to hide them, reinforce the structure and make a decoration, I bond a small piece of hardwood with an engraving.
I reproduce a traditional carving decoration form the Alps, typical folk art made with a knife (https://www.queyras-locations.fr/en/page/artisanat-queyras and https://www.amazon.fr/Mod%C3%A8les-sculpture-couteau-populaire-Queyras/dp/2851010697).
It allows me to mention the year of fabrication of the kayak.
The structure is now finished. I have used a Danish oil to protect the wood. The oil was very thick and dried before I could wipe it with a piece of tissue. I had to ask some additional forces with the help of my children.
As expected, the kayak is incredibly nice with mesmerizing natural forms.
Skinning and coating the kayak
When I started to plan the construction of the F1 in 2019, one issue was the choice of the skin and of the coating. I asked skinboat.org if it was possible to receive their fabric and the two parts polyurethane. But the answer was negative. In had no more chance with the contact of Brian in United Kingdom.
The only source of fabric on internet was extremtextil and I bought here the quantity required for my two kayaks. After, I have red comments on this fabric on the student blog and particularly the post of Axel in France. Axel encountered difficulties with this fabric. It leads Brian to put a warning on this fabric on the kayak construction course.
With the experience of Axel and the recommendation of Brian I decided to sew the fabric dry. To avoid the risk of the large thread holes observed by Axel I have chosen a strategy that finally works well in my process.
Regarding the coating, the general recommendation for European builder is to use Coelan varnish. However, the recommendation is completed with a warning on the toxicity and on the cost of the product. As I was looking for alternative products on internet I built a table to summarize some possible choices and compare them to the 2 parts urethane best choice. I consider a surface of coating about 6 m².
Among the products, one seems interesting for its characteristics. The company Soloplast presents its varnish as follow:
– Highly resistant to UV and to extreme climatic conditions
– Long-term elasticity and long-term protection in marine conditions
– Long-term gloss and wood protection against yellowing and bleaching
– Quick drying for a rapid alternation of varnish layers
Another good point is that the varnish is produced few tens of kilometers from home, in St Egrève, Isère. Lastly, the price is in the order of the product proposed by Skinboats.
I have no idea of the behavior of this varnish on the nylon fabric, so I have made some test on a piece of fabric on March 2021. I apply some resin on a nylon put in tension in a plastic frame and use a soloplast satin varnish, I use also another varnish from the table. The soloplast varnish leaves a very thin layer of resin and I had to alternate several layers before the fabric mesh could be invisible under a uniform surface of resin. The other varnish was from an old can, so it is difficult to conclude. In my case, its adherence on the fabrics was not good and I could remove part of the coating with little efforts.
On the photography, we see the two tests with the soloplast varnish on the right. I used 9 layers to have a good rendering on the fabric. I measured the thickness at the end of the process. Starting from a fabric thickness of about 450 µm I finish with about 800 µm. It corresponds well to the data of the varnish supplier: about 30 µm/layer.
After few weeks drying, the resin layer is tightly bonded to the fabric, the result seems satisfying. I have let it few weeks on the direct sun in summer with no modification. I have let it one month in water, the resin has bleached a little but the adherence to the nylon is still OK.
I have made the choice of the soloplast gloss varnish and commanded 7 cans of 750ml.
I have made the choice of the varnish, but I still have the issue of the extremtextil fabric that could be difficult to lace without generating big holes like Axel.
The use of a varnish that requires numerous layers, but no stress on mixing and applying, brought me to consider an alternative way to lace the fabric. After a first layer of varnish the nylon looks nearly the same, excepted that the mesh is stabilized. I use this observation to reinforce the mesh on the location where we made the lacing. This option will leave a visual signature. As I plan to color the fabric with acid dy, the color will not penetrate where the resin is laminated first. I take the risk and try to do it as nice as possible. I have made some test on a piece of fabric and effectively the mesh of the fabric is very fragile. When the lacing is tighten the mesh is locally destroyed. On the other part I have defined a zone with blue tape and cover it with one layer of varnish. The lacing is made 24h after. The fabric seems strong and I can lace with a lot of tension.
The fabric is put in place on the kayak on the afternoon of day 1. Day 2 early in the morning I have sewed the stern and the bow and cut the extra fabric. As recommended by Brian and based on the experience of Axel the sewing is done with a dry fabric.
As Brian proposes to leave an overlap on the fabric of ½” instead of ¼” for the extremtextil, I use a guide of 1” thick instead of ½” to cut the fabric on the stern side. On the bow side, I cut the fabric on the opposite border of the foredeck stringer (with no groove required in the center of the foredeck stringer).
Then I laminate the resin on top of the fabric on a location where the lacing go through the mesh. It was hard to find the good solution to define, with the blue tape, a uniform and clean varnish zone. I was planning to pin the skin on the foredeck but the fabric was already too short and it was not possible to put tension on the fabric. I have tried to tight the fabric with a long piece of wood and some clamps but it does not work at all (see photo). It was not possible to bond cleanly the tape on the fabric. Fortunately, I had a piece of panel in pinewood (about 13cm wide, 1 cm thick, 2 m long) that I cut to the right shape and locate from bow to coaming on the deck to have a strong flat surface above the fabric. I have pined the fabric on top of this strong flat surface and it was easy to bond the blue tape and then to apply the varnish with a brush. The panel is just returned upside down to make the varnish line on the right and the left of the kayak. I used the same panel on the stern after cleaning residue of varnish on the surface. At the end I removed the blue tape and let it dry. The weather was quite hot on this month of August with temperature above 25 degrees the afternoon. I planned to do the lacing the day after, early in the morning.
Day 3 early in the morning (7h30) I started the lacing. On the stern it was very difficult to tight the fabric to recover my ½” overlap. I had to put a lot of tension on the fabric and I think the result would have been catastrophic as noticed by axel (who had to put a patch on the stern fabric) without the line of varnish. With this alternative, I finally succeeded to find an overlap of about ¼” on the fabric but with a lot of tension on the sewing (distorted mesh as shown on the photo).
The sewing on the bow was easier with a good overlap. At 11h 00, the fabric was sewed on the structure and the coaming in place. The high temperature part of day was starting.
The same day the fabric was colored with a mix of brown (~ 90 %) and Aztec yellow (~10%) acid dy. Drying the fabric with the iron was efficient and smoothed the mesh nicely.
The first layer of varnish make appear clearly the varnish lacing line but the visual aspect was not so bad. The coaming was partly colored with the dy despite having put blue tape protection. For the next kayak, I think I will put a layer of varnish day 2, to protect it better before installing on the fabric.
I used a standard roller to put the 3 first layers of varnish (with 24h between each layer). Then I moved to a foam roller but the result was not good, it was leaving small bubbles. I came to a standard roller then.
I think the good option is to use a standard roller for the 4 first layers, then use a large brush. I will try this for the second kayak.
I put the first layer on the bottom of the kayak then I return it and apply varnish on the top and on the coaming. I let it dry in place. The day after I move a little the kayak on its support for not leaving a trace and start again the process.
I have made 9 layers on all the kayak surface and a 10th layer on the bottom. The result seems ok. I think this varnish works for the extremtextil fabric, it has filled all the gap on the mesh. Its use is easy but long, with 24h between the layers and 10 layer it takes about two weeks to coat the kayak.
I have used 7 cans of 750 ml varnish. 133 € TTC (www.sodemap.org)
Manufacturing the toggles
My objective was to follow the recommendation of Brian and manufacture the toggles in a piece of HDPE. When I have looked on internet where to buy this material I have seen that this plastic was commonly used in a lot of everyday objects from the bottles of shampoo to the bottles of milk. I toke the game to look for the recycling logo “HDPE” everywhere.
To go further in this investigation I have tried to melt small pieces of HDPE together to see if I was able to recycle some plastic waste into toggles. The result is surprisingly nice.
I have used for this 96 g of white HDPE from bottles of milk and 5 g of yellow HDPE from a chocolate box. The bottle of milk is white but in fact, it contains a black layer between two white layers. This alternation of color gave a very nice visual result with a Damascus pattern.
I used a oven at 200°C and a weight of 5 kg to press on the HDPE flakes. The 100 g of plastic was just sufficient to made the four toggles. The result is nice and the pieces seems strong without delamination or defects. I suppose this process makes the plastic more fragile than the one we can buy as raw material. But it’s a funny alternative.
Foam Thigh brace
To make the foam thigh braces to the dimension given by Brian I used a yoga block from Decathlon store. Just 5€ and the good dimension to shap four braces.
Building of the second kayak
At the end of 2022 I started the building of the second kayak. The step of steam bending the ribs is harder than for the first kayak. The risk of running out of ribs is critical, I have to manage as I can the splitting of various ribs.
I finish by adding my last spare rib. I came across this difficult step. The results seem ok but I will reinforce some ribs latter with an additional pieces of curved wood.
While I put the stringers I realize a mistake I made in the first kayak. The orientation bow/stern & aft/forward of the stringer is important. I did not notice this point and I made the wrong choice and then choose to fix the stringer in the only way it came naturally. I put the long side of the stringer rectangular section in contact with the ribs, the right way was to put the small side… I have tried to figure out what could be the consequences. I suppose I should lose some primary stability, some volume and some strength.
I contacted Brian who was more curious of the results on the water than afraid by the mistake ! So just wait and see, the good point is that I will have two different kayaks to test :o) !
The rest of the process is done without problems. I use again the technic of pre-coating part of the skin to avoid the defects of lacing with the extrem-textil fabric. As in the first case I can tighten the skin very hard without critical holes. This time I coat the coaming before installing it on the skin. By this way I was able to avoid the dye to penetrate inside the coaming wood even with the tape protection. Once again I sew the skin dry.
After acid dying with a mix yellow/brown I use the same varnish to coat the 9 layers on the skin.
I fix the perimeter lines with some homemade attachments built from pieces of plastic (cut from an old flower plant pot) and portions of nylon straps. I fix the form with hot-melt adhesive and then I screw to the gunwales with two screws after forming pilot holes.
Both kayaks are now finished. The result is great I found that the pre-coated lacing line gives something organic to the skin.