Tag Archives: sanding

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 PartV

The race to be done for my vacation is still on. But I’ve resigned myself to the reality that the first week of my vacation will be spar making and rigging the boat. The finishing line is in sight, but there is still so much to do.

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I’ve tackled the main mast shaping going from 8 sided down to 16 sided, then 32 sided and 64 sided.

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I used a used West Systems thickening powder container as a sanding backer and pulled out some sand paper left over from sanding my floors a couple years ago. I started with 36 grit to cut down the corners. Then 60 grit, and 100 grit sandpaper.

Sanding, sanding more sanding

This was hard work and Vancouver this summer is going from one heat wave to another. Fortunately I went out an bought a large ventilation fan that I mounted to the rafters of the shed. This has worked wonders to help me keep cooler while I work up a serious sweat sanding.

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I then cut the mast head to a smaller diameter with a router. This will create a nice saddle for the shrouds to loop onto the top of the mast.

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I did most of the shaping with the Japanese rasp and finished with the random orbital sander.

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I think the scalloped ends of the plug and birdsmouth look really cool.

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Using this portable guide I drilled the ends of the mortise for the halyard sheaves.

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The tricky part was drilling the hole for the axle at 90 degrees to the mortise.

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I’ve also sanded the sprit boom and the boomkin and finished the ends on those.

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Then onto the mizzen mast. Where I experimented with the difference of using the power planer.

And using the drawknife to cut down from a tapered square to the 8 sided shape.

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My conclusion is that with the drawknife guides it is much easier to control and likely just as fast as the power planer. If kept sharp it is almost easier and certainly quieter and less messy overall. It is way easier to pick up the shavings than vacuum up all the sprayed chips sent out by the power planer. I found it gets me quite close to where I need and then I can just finish it off with the jack plane and the block plane.

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The mizzen mast is now complete. I now have three days to complete the main boom and yard. Then I will lay everything out and varnish them with 6 coats.

Caledonia yawl project: preparing the gunwhales

This weekend the weather started to turn through the day on Saturday. In the morning it was wet and warmish. But as the day wore on the forcast bore itself out and the temperatures dropped steadily to -9 overnight. With this in mind I decided to forego any gluing and do more things that would set me up for some productive days of gluing when the temperatures start to rise.

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I started by sanding all the fillets I had done in all the interior laps. The last set of fillets I plan on doing are between the aprons (inner stems) and the planking. This will strengthen the bond and present a better surface for painting and keeping clean.

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I also cut all the scarfs needed to lay up three laminations od 1/2 ´´ thick Douglas fir that will be  nearly 21’ long once glued up.  I just found that my last pieces were a little knotty with some grain runout and so I could only get 8’ out of them. I will need to get two more lengths of 13’ 1/2” strips to have all the materials ready.

Caledonia yawl project: sanding, fairing & more sanding

This is the part where the changes are almost imperceptible but where so much of the final appearance of the boat rests.

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I’ve sanded and added low density fairing epoxy filler to the parts that needed it. Then the process of sanding continues. Each time a thin layer of dusts covers the hull everything appears more fair and smooth. This dangerous as I have learned when mudding drywall, what lies beneath needs to be exposed to be sure there aren’t any bumps, holes, bubbles or ripples that would be even more apparent once the paint is applied.

Caledonia Yawl: hull preparation

The work has progressed in small increments on the hull. Each step did not really reveal a significant visual transformation that might show up on the camera. But they are small changes that will allow the hull to look great once painted.
I glued up the keel and the stems:
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and after a few repeat visits added the keel pieced on either side of the centreboard slot.
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Then we got to work sanding and planing down the keel and stems so that they were fair to the eye.
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and distracted myself with paint selection ideas:
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and put fillets of epoxy mixed with low density fairing filler in all the laps.
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I then decided to add a small rub strip of wood on the lower edge of the sheer strake. The idea being that I like the way in helps to frame the sheer strake and that it might also serve a small function as well.
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The last step before really getting down to the final preparation for painting is the outer gunwhale.
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Caledonia yawl project: final shaping of rudder and centreboard 

Experience in working on gyprock and mudding all the joints and corners and having to then sand them down to a fair blend to the straight board stock, is that it is worth spending a little more time sanding even if to the eye and to the fingers it appears to be smooth. 
  
Once I add the unidirectional carbon fibre and epoxy I will certainly discover new spots that are not quite right for the centreboard and rudder NACA profiles. Sanding down epoxy is much harder than bare cedar.

I’m feeling fairly confident about the shape now and I’m looking forward to adding the epoxy and carbon fibre.

   
 

  
This beautiful cedar will soon disappear behind layers of carbon, Kevlar and graphite. The only part of the boat I felt would benefit from additional strength beyond just wood fivers.

Caledonia yawl project: kerfs, planing and sanding

With a bit of further reading and some confidence building after my first set of kerfs on the starboard side of the centreboard I’m back to work on the port side.

 

It is slower progress but hand planing really makes you feel the wood and control the shape.
  
 

After removing the bulk of the material with the power planer, I switched to the small block plane which seemed to work better than the larger plane with the cedar and the curves. It also is pleasant to work making almost no noise and creating nice wood shavings and no dust.

For the transition to the part of the centreboard that pivots I need to use my random orbit sander with 60 grit. Ideally I’d like to use a disk sander or a belt sander.