Preparation and Trial Build?

Builder's Forum
1

Folks,

I am building a C17LT from plans. I have no experience with woodwork or epoxy. (I realise that kit may have been more prudent approach ...)

I was thinking of practicing on some cheap 4mm marine ply. ie transferring and cutting out the parts, then creating the hull up to the stitching stage. 

Does this seem unnecessary? Should I just get stuck into the job on some better quality marine ply and actually build the real kayak.

I also had an alternative  suggestion from to practice some of the elements on ply like scarfing and filleting. This seems like a good idea.

Appreciate any feedback and guidance

2

   Cheap ply will not cut, bend, plane like the good stuff.  Maybe get one sheet of cheap stuff and practice cutting the scarfs.  Rip it into 1' wide panels then scarf them and make long boards. The only thing is don't expect cheap ply to plane very well.  You'll have to use a grinder or sander on the scarf tapers.  If they come out the same size and straight, do it for real. And you'll have some long battens you can use for laying out fair curves, transferring lines, etc.  The filleting you can do in several small stages on the real deal.  Do one small stretch and see what goes wrong so you can do it better next time.  Mostly it's reducing the amount of sanding and grinding by being neat, cleaning up edges, smoothing while green.  I still mess it up on my 3rd kit.  That's what sandpaper is for.  Buy the 80 grit in 50 or 100 sheet boxes and change it all the time. Besides, in a kayak, they can't see most of the fillets anyway!  So it winds up a pound or two heavier.  Eat fewer burritos before paddling!

Now varnishing, that might be something to practice on a leftover before getting serious.  I had a 2' by 4' piece of leftover 3/4" ply.  I sanded it on the good side, used leftovers from my epoxy seal coats on the boat to seal it and leftovers in the varnish cups from each varnish session to coat it.  It's the best looking portable work surface you can imagine! I sit it on my sawhorses raw side up to do cutting, trimming, drilling, then flip it over and have a smooth shiny surface when doing little fiddly things or just to layout my papers and look good.

3

Mick,

Since the bends on the 17LT are so gentle, I think that practicing the layout will work fine with even cheap non-marine plywood, let alone the cheap marine that you mention. But I don't think you have to go ahead and build a full scrap boat, even if you've never done any woodworking before.

If you just get good at the following skills, the rest will be relatively easy and come to you while building

1. Reading plans. If you don't know what you're building you can't build it. You don't need any plywood for this.

2. Accurately transferring dimensions. You don't need any wood for this, either. Any flat surface will do. Just compare what you've done to the plans.

3. Cutting wood with a hand saw. This one only needs small pieces of scrap at first. When you're comfortable with cutting small pieces, try a large one. Think of this as practicing scales on the piano. Remember also that you don't need to cut to the exact final dimensions. You can alsway cut a bit large, then sand, rasp, grind, plane (or whatever your favorite wood remover is) down to the line.

4. Drilling holes. Should be very quick, mostly just getting used to the drill itself. The actual drilling is easy.

5, Cutting scarf joints. This is the advanced piano exercise analog. Mummichog's advice to use good wood here is spot on. This is going to be the most important if you're building a varnished boat. If you're going to paint your boat, epoxy and fiberglass will still let you get all the strength you need, even with an ugly joint.

In my mind these are the critical woodworking skills that it would make sense to practice beforehand.

As far as the epoxy skills go, I'd wait til the actual build, as Mummichog suggests. Until the epoxy cures, you can always pull off the cloth, scoop out the fillets, etc. so the worst that will happen is that you use more material. I'd suggest buying half again as much as you need (if the budget allows) in case you have to do something over. You can always use the extra for repairs later.

If you haven't already done so, read over the CLC Shop Tips. Lots of good info there.

Have fun,

Laszlo

 

 

 

 

4

   i'll take an alternative view on practicing some of the epoxy stuff.....becuase when you get it wrong it can be a big hassle...and the big 'wrongs' that are really hard to deal with is no testing or idea of the basics  before a lot of material is put at risk..

  while you can't simulate everything, i think the following are worth wasting a little bit of epoxy on (less than 2 small cups) to build confidence in some basics...especially if you haven't done any of this type of thing before.....

  1. i would mix a small batch (1/2 cup - 3 to 4 oz) and confirm you know how to mix it (that the ratios of hadener to resin are set correctly) and it hardens...let it harden....and think about how much time it took.
  2. i would use a second small cup (1/2) to wet out a piece of glass on a scrap piece of wood (a square foot is probably all you need) just to see the glass turn transluscent and how to use a sqeegee to take off the excess....(and build confidence in your epoxy mixing ability)
  3. i would create a little one foot long angle and fillet it....this will give you a small taste of mixing stuff like wood flour into the epoxy and getting it to a nice consistency to work with and how to use a fillet stick (or spoon or popsicle stick) to get a fillet in place and how to clean up the edges. (again, this is no more than a small cups worth of combined resin/hardener)

during this process you can also practice putting on gloves and things to protect your skin when working with epoxy.   you will also sort out your mixing area and just how to organize your space and get rid of trash.    again, not a big deal....but when i think back to my first experience with epoxy.....not a bad little confidence builder....before the stakes are raised....

even with that, you will very likely in your build make some mistakes that you will inevitably address....but my sense is if you can do the little exercise above, you can avoid the worst of anything i have seen in my 20+ years of building.

all the best, 

h

5

Thanks to all the people who have offered their advice above.

Lots of reading at the moment, and some planning too.