Days 1, 2 and 3

This project started on the 18th of February 2009 with a trip or two to get the materials.  In the end I as using:

2 sheets of 'Super light 3.6mm ply', suitable for exterior use, from BBS Timbers Limited.  This comes in sheet sizes of 1220x 2420 or there abouts and has a clean light wood finish.  I am not sure of the actual exterior wood.

West System Z206 Hardener, Z105 Resin and 406 Col Silica as a resin thickener for gluing.  This was obtained from Burnsco.

The design is one given to me to use for this project from Carl, who is a member of the NZ kayak builders forum.  It is about 2.6 metres log and looks fast.  :-).  Having said that, this is the first Stitch and Glue build of the design.

The first trick  was to join the two sheets of ply such that the joined piece was long enough for the panels to be laid out in full.  This required a scarf joint for the full width of the ply sheet.  

One Ocean Kayaks have a great resource for building Stitch and Glue kayak including a page a scarfing plywood.  It is worth a look.

Getting a tidy scarf is not easy.  I would give this effort a 7/10 but it took two tries.  In the first try I used an electric planner to speed cutting the scarf.  Not a great idea.   Not matter how careful I was, I ended up over cutting the scarf.  So I re-cut the scarf with a hand plane.  It took time and was very exacting.  Next time will be better.

The epoxy, thickened with the 406 Col Silica worked well.  There is not a lot of pot life after mixing but enough to apply the resin and set the scarf in place.  I used thin plastic to protect the ply from sticking to the bench.  This worked very well.

The resin took about 24 hours to get very hard.

I drew the panels directly on the the back of the ply.  I used the back because it allowed me a bit of latitude to make pencil marks without having to worry that they be removed.  In addition I will be cutting the ply with a jigsaw.  In the past I have found that the underside (in this case the best side) has the best cut.

The positioning of the panels on the ply sheet required careful placement.  I nearly screwed this up and had overlapping panels.  DOH.  To avoid this start form the centre of the ply and work out.  better still is to draw the panels on heavy packing paper, cut then out and place then on the ply to ensure no overlap.  I was lucky but it was millimeter close.

The panels are now ready for cutting.

I knew these computer books would come in handy some day.

Cutting the scarf with a hand plane.  Slow and exacting.

Both scarfs cut.  Note that the top piece of ply is cut upside down.  Also note the book from West Systems on applying resin.  This book costs little and is a great resource.  Get it.

When you have applied the resin then you need to clamp the joint (or weigh it down) as best you can.  A 1.2m wide scarf requires a lot of very big clamps... of just something heavy.  This is what i rustled up in 5 minutes and it worked a treat.  Don't forget to use a plastic sheet both under and over the joint so that the resin does not stick the ply to the workbench or weights.