Tag Archives: epoxy

Caledonia Yawl Project: Spar Building part VI

The boom and the yard come second only to the birds-mouth mast in complexity. The jaws required some attention to detail.

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shaping the yard

The process of going from a square piece of glued up wood to a tapered cylinder is now becoming familiar. But there are still individual particularities to each piece as you have to read the wood and each facet might require planing in a different direction to avoid grain pull out.

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I started to decorate the place with the draw-knife cuttings which are so much fun when they are the full length of the spar.

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Careful mapping of the facets when you get from 16 sided to 32 sided is worthwhile. I found that marking the 32 edges then helped me keep track of where I was when I cut it down to 64 sides. On the yard that ends up being just one or two passes with the planer set very fine. It is in my mind the trickiest part of the process.

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After sanding the yard with 36, 60, 80, 100 and 120 grit sandpaper I was onto the boom. The time spent making this spar gauge based on Harry Bryan’s design in Wooden Boat magazine 277 was worth it but it was kind of bittersweet to think this was one of the last times I’d use it for awhile. (note: I still might use it to make the oars)

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The jaws require a transition from round to square which is an extra challenge when shaping the spar. In the end once marked it is relatively easy to do.

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I still have some of the reclaimed Honduran mahogany that was pulled out of home demolitions by a renovation contractor who was retiring and selling off their stockpile of old window and door frames. I now wish I’d bought more for future projects. But for this project I have enough.

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As per Ian Oughtred’s plans he specifies the jaws should be 22mm thick and made of two pieces. I added a 5mm marine ply to the mahogany to get to 25mm and it will do well to reduce the chances of splitting along the grain on this curved piece.

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I’m also attempting to make some copper rivets according to the September 2015 Small Boats Monthly article by Christopher Cunningham for the yard and boom jaws. I was able to order #6 gauge copper wire and I’m using some leftover 1/2″ copper pipe for the roves.

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spokeshave for the transition from round to square
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The last ridge going from 8 sided to 16 sided on the boom. The last spar!

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Marking the ridges from 32 to 64 sides on the boom and then shaving them down.

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Gluing the jaws layup with the wedges so that I can do some further shaping before gluing them to the yard and the boom.

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Gluing the boom jaw pieces together.

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Then shaping the pieces into something that looks relatively nice. I used the Japanese rasp, the block plane, the spoke shave, the belt sander and the random orbital sander to get it into it’s desired shape.

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The boom and yard jaws dry fitted.

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… and then all glued up. Tomorrow I’ll do the final shaping on the yard and boom and some sanding of the epoxy. All the spars will get sanded down to 150 grit tomorrow and all set up for varnishing. I’ve also got a bunch of little fittings to make that will need to be screwed onto the spars. Most are just little thumb blocks, but I also have to make the jib fairleads. I’m getting close to being able to rig it all up.

Caledonia Yawl Project: spar building IV

This summer it is now a race to have the rigging done before we take our vacation in the second half of August. My intention is that we have the boat ready for some day trips and camp cruising. I’m setting a deadline for myself. So over the last month I’ve been regularly plugging away at the spars. I started with the most complex being getting the main mast glued up.

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I cut the taper on each of the 8 staves which was tricky as they are small pieces and hard to keep square when vertical as the birdsmouth cut did not have two even ends to rest on.

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I ended up resting them on their sides and planing them with the block plane at 90 degrees. it was easier to clamp and not too hard to keep things square.

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The next step was to make the 8 sided top and bottom plugs for the mast. The top plug had to be long enough to cover the area needed for the halyard sheaves. So i made it 50 cm long as I will have the sheaves one on top of the other instead of side by side.

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Dry fitting the top plug into the tapered mast. That was the more complex part of the exercise. Getting the inner diameter taper right. Fortunately this does not have to be perfect as a little space can be filled my thickened epoxy.

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Mapping the taper of the the base plug of the mast I decided should be longer and go as high as to where the boom rests against the mast. Partly because I’m thinking of fixing the cleats for the halyards onto the mast and would like to have more material for the screws to grab onto.

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Testing the diameter of the base plug with an off cut of the main mast staves. This piece was longer and the taper a little trickier to get right as it covered both a flat section and the reverse taper at the base.

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Then I cut out a taper of material on the inside of the mast plug to ensure there are no hard edges that could impact the flex of the mast or create a breaking point.

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Finally everything was ready for gluing. I decided to do this in two steps. gluing up the staves in two clamshells by taping two of the birdsmouth sides. This will allow me to then on the second step to glue in the plugs and the remaining two stave edges.

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I put all six of the staves to be glued upright and slathered them in unthickend epoxy and then squeezed the microfiber thickened epoxy with a piping bag.

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14″ Zap straps worked great to clamp it all together and a bag of 100 was way more than needed. But we have my friend’s two masts for his Penobscot 17 schooner rig to do later. I did use vice grip pliers to pull the zap straps tight. I found this really made a difference.

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Once the epoxy cured overnight I was able to open up the clamshell and remove the clear packing tape I’d used. I did a little clean up of the squeeze out epoxy on the inside where the plugs would go using a heat gun and a small scraper.

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But left things as the are for the rest of the mast. I also decided not to coat the inside with epoxy. my reasoning is that it might be worthwhile to let the wood breath on the inside. There should not be any water ingress or holes in the mast.

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Then the final glue up of the main mast with both plugs well coated in thickened epoxy.

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It was such a pleasure to get to this point and see this complex interlocking set of small pieces of wood come together into a solid monolith.

I will weigh this mast as in theory you save approximately 35-40% of the weight by building it this way. It is however a significantly longer process to make. Some advantages is that you can work form smaller stock and with a few scarfs not necessarily have to have full lengths that you need. Building a solid mast with two pieces glued to each other however would be much faster and for a boat this size with sitka spruce maybe not yet unmanagable as far as weight. I’d be a little more reticent if I had to work with douglas fir which is very strong but also heavier. I feel very fortunate to have had the time to source sitka spruce.

Caledonia yawl project: the frame unveiled

Yesterday I snuck back to the boat shed with my little apprentice.

We found that the epoxy had set nicely. So far I’ve yet to have had a problem with the West system epoxy even when skirting the edges on the temperature limits of the 205 fast hardener. But it is always a nice relief to find the laminated Wood solidly bonded.

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So we started the process of removing the multitude of clamps holding the laminated frame for 24 hours. I then put it in the hull at the appropriate location.

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The epoxy squeeze out still needs to be cleaned up and the whole frame will be planed down to 1″ thick. The outer frame will be bevelled to match the angle of the hull and the ends will be cut down to mate with the completed inwhales.

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I also flipped the frame upside down and found that it looked like a great shape to mimic for an eventual canvas cover for camping… But that is a project for much later. First I need to finish the inwhale laminations and continue to fit out the interior of the boat.

Onwards, regaining momentum feels good.

The seventh strakes (sheerstrake) and the Whiskey plank

The last two strakes,  are called the sheerstrakes as they  mark the sheer line of the boat’s profile.  The month of December has been colder than usual and so the progress has been arrested a little as I waited for the weather windows when the temperature is above 5°C or close enough so that the epoxy will set.

I was able to get the starboard sheerstrake glued early in December,  but the port Sheerstrake had to wait for the Christmas break.

Strake 7

    Starboard strake no. 7

Port seventh strake all glued up.

Seen from inside where I crawl to remove any squeeze out glue

All glued up and ready for the outer stems soon

Once the glue set for the port side I was able to declare the hull complete.  Tradition has it that the occasion is celebrated with with a little whiskey.

Next up is the planing of the bow and stern stems so that I can glue the outer stem pieces I made earlier.

Caledonia yawl project: cutting the gains on the garboard 

Today I tackled something new, cutting  the gains on the garboard so that the second strake appears to taper nicely to meet the profile of the garboard as it gets to the bow and stern stem.

To accomplish this I needed a rebate or a shoulder plane, which I don’t yet have in my tool kit. So I got a membership to the Vancouver Tool Library to allow me to access the tools I don’t yet have. As you might imagine shoulder planes or rebate planes are not super common tools, but they are precisely what makes the tool library such a wonderful service. I can easily imagine some kind of franchise where clusters of a few blocks have something similar.

Continue reading Caledonia yawl project: cutting the gains on the garboard 

Caledonia yawl project: laminating the knees and carbon on centreboard

Today I helped my friend get a new fridge in a house where the widest door was 28″ wide. We had to take apart the sliding door.

 

everything is back together but you can see the areas where i dug out the nails
 
This evening I managed to get a couple hours and I put the unidirectional carbon fibre on one side of the centreboard. I wet the surface with epoxy and the layed it down and squeegeed more epoxy onto the surface.

  
It’s not perfectly smooth, but I’m happy with the result. I’ll be covering it with graphite epoxy soon and that will be sanded smooth.

I also started laminating the knees that will connect the thwart to the gunnels.

  

 

I used 2 1/4 thick fir lamimations left over from making the stems. With some luck ill be able to cut them down the centreline and get two knees out of each one.
 

Caledonia Yawl project: laying Kevlar on the rudder blade

This probably lies somewhere between overkill and preventative engineering. I decided to lay some Kevlar fiber on the rudder and centreboard leading edges to deal with the wear and tear of a beach boat that will regularly come in contact with the shoreline and may at times bump up against the sand, gravel or rocks on the shoreline. In our part of the world floating or partially submerged logs and driftwood are also a concern.

Kevlar wrap over the leading edge
Kevlar wrap over the leading edge of the rudder
Continue reading Caledonia Yawl project: laying Kevlar on the rudder blade

Caledonia yawl project: Buying the keelson lumber and preparing the centreboard 

Back out to Fibertek to buy more epoxy with my assistant.

The apron and stems took much more expoxy than I had anticipated. This time I splurged and bought the gallon of resin and hope that I won’t have to make a trip back here soon.  Note that the 15′ 2×6 douglas fir on the Larry vs. Harry handled fine.

Continue reading Caledonia yawl project: Buying the keelson lumber and preparing the centreboard 

Caledonia yawl project: planing the bow apron and stem

Having access to a thickness planer makes this activity much easier and more precise. I was able with relative ease to plane the whole length of both the apron and stem down to the specified thickness on my own. I did spend some time fretting about keeping the angles square and not ending up with a weird parallelogram that would give the bow a weird twist. fortunately the thickness planer coupled with a square and some judicious hand planing kept everything progressing smoothly. When planing the apron down to the right 2″ thickness i was sure to keep checking that it was square.

Continue reading Caledonia yawl project: planing the bow apron and stem

Caledonia yawl project: gluing the bow stem

When I ripped the strips for the bow stem I was not sure what the appropriate thickness would be so I played around with everything from 1/8″ to 3/16″ and up to 1/4″ most of my strips were 1/8″ thick.

Which meant that to create a 3″ thick stem I needed nineteen strips. Each strip needed to be buttered with epoxy and with so much surface area that turned out to be about 850ml of epoxy  or nearly a whole can. If all my strips were thicker I would have used much less epoxy. The lesson that I learned is that when laminating use the thickest strips that the mould will bear.

 

Nineteen strips of Douglas fir waiting for the epoxy

 

Then Fortunately Patrice came out to help me with the laying out of the stem on the mould.

a fair bit of epoxy squeeze out