Rip

It's been a busy couple of weeks leading up to the Thanksgiving holiday but I found a little time to dedicate to the kayak Sunday after my family gathering.  My original plan was to scarf the boards together before ripping them into strips but I ended up ripping the boards first instead.

I wanted the scarf joints to be an 8:1 ratio to maximize the glue surface for making a strong joint.  This meant that for a ¾” board I would need to taper the ends 6”.  That’s pretty difficult without proper woodworking tools but I gave it a go.  I tried a band saw but the blade wandered too much.  I tried hand planing but it was inaccurate and labor intensive.   I built a dedicated miter box but the tapered ends were getting damaged.  Wood chisels and a hammer gouged too much and sanding on a belt sander was, well, just a silly and desperate idea.  I needed a better solution.

I turned to the Blue Heron kayak builders forum for advice and got a great deal of positive feedback.  The general consensus was to rip the boards then scarf as needed.  I was also told to not get too lost in the details about the length of the joint as a simple butt joint would suffice.  Some of the builders even leave their strips short then create joints as they apply the strips to the forms.  I had fallen into the trap so many novices do in unfamiliar territory.  I made an assumption that the standard construction method is to use long strips then I set about that course without considering alternatives.  There is always another way to do just about anything so keep your mind open and find what works best in a given situation.

Armed with this knowledge I ripped about a third of the lumber this past Sunday.  To do this I used a 10” Skill cabinet table saw with a Freud Diablo Ultra Finish blade (D0760X).  Any sturdy table saw is powerful enough to cut the strips but the blade is important.  The Diablo is a thin kerf 7.25” blade which helps minimize waste.  I picked this blade because it was recommended by other builders and for $20 I felt it was well worth the price.

 This is the Diablo D0760X 7.25” 60T blade with my magnetic Rigid feathboard.

I marked the ends of each board with two orientation lines prior to ripping.  One line was horizontal and one diagonal.  This helped me keep them in order after they came off of the table.  The only reason to do this step is if you want to matchbook the grain but it’s not necessary. 

I then fed the lumber through the saw cutting each strip proud of ¼”.  The plan was to get close with a little room for error.  Unfortunately the table saw top was aluminum rendering my magnetic featherboard useless.  This forced me to push the board both from the end and the side so that it would stay against the saw’s fence.  I don’t recommend doing this as you can quickly end up with shorter fingers.  Ultimately I ended up with a pile of strips that were slightly variable in thickness.  A few passes through the planer will take care of this problem but using a featherboard would safely yield much more consistent strips without this extra step.  I plan to do it anyway to get rid of saw marks and make a smooth surface on the strips.

 I’ve abandoned the blue painters tape in favor of plastic wrap for keeping the strips organized.  The tape wasn’t sticky enough.

 

I hope to have some time this coming Sunday to plane the strips.  December is going to be every bit as hectic as November and spare time will be a rare commodity!

Plane

It's time to plane the wood.  The weathered and rough surface has to go and the boards needed to be a consistent thickness.  My new Dewalt DW734 thickness planer arrived from Amazon last Monday and was ready to roll on Saturday. 

 I fed the wood from my truck bed through the planer then stacked it on the table in the background.

I started out with the thickest board in the pile and slowly planed it down to 3/4".  I passed the board through, lowered the cutter head 1/64th of an inch then flipped the board and passed it through again.  I repeated the process until both surfaces were smooth and clear all the way across then I planed the same side to remove any blemishes.  I set it aside, grabbed the next board and continued the process until all were complete.

The Dewalt DW734 in action.

Some of the boards were a little warped so several successive passes were needed just to get the surface flat.  I also had a couple of boards that were already 3/4ths of an inch before planing.  I went ahead and fed them through the planer but removed as little as possible.  They'll probably come in handy for the chines where more narrow strips will be needed.  I also edge planed the boards that were previously set aside for scarfing so they're a consistent width.  The black bar across the top of the Dewalt's knife head will lock it in place which prevents snipe.  Very useful.

I ended up with a stack of beautiful paulownia that's ready for the table saw.  I plan on scarfing the boards next then quickly planing them a touch more before ripping.  Right now I'm having trouble figuring out how to taper the ends of the wood to make the scarf joints.  I've tried a band saw, block plane and wood chisels but the 1:8 ratio for the taper is going to be really had to achieve.  You can see a 1:4 taper in the picture below and that's really tough to do.  I have three options to make the taper.  I can carefully saw, chisel and sand each end, take the lumber to a mill work or cabinet maker and let them taper the ends or I can go ahead and rip the boards then make scarf joints on the individual strips prior to putting them on the forms.  Right now I'm leaning towards making the joints on the strips.  It'll mean more work but it's probably the most practical solution to the problem.

 Note the tapered board.  That was done with a hand chisel then sanded on my benchtop sander.

 I love the light color of the wood.  Beautiful grain too!

I'm finally putting the rungs under the strongback mount to use as a storage place for the boards.  They're out of the way but still handy to grab.

Form

After building the strongback I put together a set of spacers for the forms.  This allows me to lock in the form boards without screwing them in place.  Each spacer is precisely 11.5” with the exception of the center locking spacer.  This one is cut into two parts and made to accept wedges so I can snug the whole setup together from the center.  The rest are simply 1” x 4” boards screwed & glued to form a U-shape that slide over the strongback between the form boards.  After they were built I was careful to square up each end with the sander.  None of the spacers are screwed to the strongback.  Below you can see the center spacer with its wedges.  I used pressure treated hardwood because that’s all I had left after assembling the others.  There are 13 spacers in all. 

 

As you can see we here at KudaMuda’s Kayak Shop undergo some pretty rigorous QC by our in-house lab.

The form boards are made from particle board and have little nubs on the outside edge and inside where they slide over the strongback.  I used a file to remove the ones on the inside and my bench top belt sander for the outside (Ryobi model BD4600 4" belt and 6" disk sander).  Once removed it only took a few minutes to slide on the numbered forms and insert the spacers.  The plans include a measurement from the bow end to the cockpit.  In the pictures below the forms are in place but not secured.  I will need some shims for the nose pieces before I can screw them to the strongback and I won’t have those until I rip the lumber.  Everything right now is just test fitted.

 

Note the nose piece for the stern is not in place here.

There are virtually no instructions for the kit.  You do get a few key measurements but there are absolutely no written instructions on how to proceed with assembling the strongback or forms.  They don’t even tell you in what sequence to install the forms.  The only written instruction is an update to Schade’s book which I suppose is intended to be your construction guide.  For the cost of the kit I don’t think including a one page assembly guide would be asking too much.  Just be aware if you do purchase a kit it’s also a good idea to buy Schade’s book.  While it won’t provide specific instructions on what to do with the pile of wood that comes in the box it will give you enough insight to figure it out on your own.