Thread: Beginning the unnamed build

19mm ply might not be as warp-free and may need a little more persuasion to keep the edges aligned correctly. Also, because of the crossed grain, finishing the edges cleanly may be more difficult. However, these aren't huge problems, and if it's free..............

Thickness is just whatever is reasonably stable while still being easy to work. 19 is fine.

I use whatever I have available and have never had any problems with any of the materials I have used for forms.

I have used 9mm MDF, 13mm ply and 16mm ply. If I had free 19mm ply, I would use that. I have even built a couple using a mixture of 13mm and 16mm ply. The strips only touch the forms on the edge closest to the end of the kayak, so thickness isn't really an issue.

Unless you are a lot quicker than I am, I suspect your time will be closer to 200 hours than 120 hours.

I have built nine strip built kayaks and they have all taken around 200 hours. It seems that I can't help myself. Whenever I have a design like my K1, which is quicker to strip than a sea kayak, I put more time into something like an inlaid sheer strip. When I built my granddaughter's 3.7 metre kayak, I spent extra time making a wooden seat instead of my usual closed cell foam seat.

Did you post your design on the Blue Heron forum for appraisal by other builders? Unless you are very confident, that is a good idea to make sure you aren't going to spend 200 hours and a few hundred dollars building a kayak that doesn't behave the way you want it to. Perhaps you have everything under control, but I have seen some first attempts at design that would have been dreadful things to paddle.

So from the comments here it seems like 19mm ply will be fine for the forms. Thanks for the feedback as saving a few bucks always helps.

Anewhouse, I have posted the design over at the other forum and they are certainly a helpful bunch, yourself included and I believe I've got something that is reasonably dialed in for what I want. I must admit that it took about 7 iterations of the design before I ended up with something that I liked and seemed to meet the general design principles for a decent kayak. In saying that, the design has just been sitting around for a bit over a year, so its good to finally be beginning the build.

I tend to use what hanging around in the shop, though usually I employ scraps of 1x4 (19x38 mm) and 1x6 (19x150 mm) solid pine stock. This stuff is cheap, usually full of knots and defects, but I cut around much of it and scab them together to make up station molds, stem and stern molds, etc. Some drywall screws, maybe some wood glue, a scrap piece of plywood as a gusset, etc. It's easy to cut, takes fasteners on it's edges well (big plus over plywood or particle board), tolerates moisture and I can knock it apart afterward, without guilt over it's use (cheap). I've reused portions of old molds a few times, so it easily justifies it's use.

It's also important to work up a name for the project. Even if you change the name, the boat building gods will require a wee bit more, than occasionally cursing about the "bitch", as they can get easily confused and the the other half, may fall victim to your frustration over your boat, unfairly. This unnecessarily burdens your better half and if she catches wind of your indecision and resulting bad confrontations with the boat building gods, you will naturally become the victim as well. I've seen this countless times and it's wholly inappropriate, making your efforts just that much harder. Spare yourself this difficulty and offer a token name for the project, before bad mojo lands on your butt.

So I've now prepared the plywood forms for cutting by glueing on the paper templates. Hopefully I'll get some time tomorrow to rough cut the forms to shape.

time spent:

glueing the paper templates 1 hour

total time: 3.5 hours

Well I managed a bit of shop time today and got all of the forms rough cut to shape, and ended up with what you see in the photo. As I was using a jig saw I was fairly conservative, and I believe I may regret this when it comes to getting the forms down to the line as I left about 3 mil proud.

Rough cutting of the forms - 2 hours

Total time 5.5 hours

Got a router? That would probably be the easiest way of getting rid of most of the excess, unless you have one of those stationary disc sanders. Other way of doing it is to get a handheld belt sander and fix it upside down or on its side on a bench, then use that much like a stationary disc. A bit tricky getting it well secured though.

A router sounds like a good way to get things about 0.5-1mm from the line. The last part I think I'll either go to a rasp then sandpaper or see if I can borrow my friends belt/disc combo. What does everyone else think about cutting freehand on the router?

Originally Posted by Mr Big

What does everyone else think about cutting freehand on the router?

Far too scary for me although I'm sure some people could manage it.

I'd go with a mounted disc or belt sander.

Go for the stationary sander if you can borrow it. You can do it right to the line with a router, but it's a bit of a nuisance.

For future reference, when using a jig saw,, cut right up to the line, leaving only the pencil mark showing. If you go slow, have a sharp blade and take care to let the blade do the work, instead of pushing hard, you can get very precise. If you find the blade is wandering in towards the line too much, just stop, back up and adjust your angle a tad. You can cut within a mm or so of the line with modest practice. It helps to know your tool, as each will tend to wander in a specific direction. This can be midigated to a large degree with a good saw and sharp blade. Maybe practice on some scraps, cutting to the line but stopping and readjusting if you wander off course and start to ding the line or veer away too much. Simply stop, back up and redirect the saw on the line you want.

So with a little shop time organised on the weekend, I have now refined about 3/4 of the forms down to the line.

First up I tried routing to bring things a little closer to the line. This produced a very inconsistent result with a fair bit of mucking around, it was also very hard to see how close to the line I was getting as the paper folded up instead of being cut.

Next Up I pulled out the saw rasp and went at it to bring things right down to the line. This worked very well, but took a while to complete just the one form.

At this point I just gave in a decided not to wait for my friend to get back from the farm to get going further, so after a quick trip to supercheap auto and $99 later I now have a light duty belt/disc sander combo. Not the greatest machine, but it is certainly getting the job done. Only complaint is that in it's current setup, it does shake a little until you steady it by adding the work piece and the motor is not really rated for continuous duty. So after 1.5 hours of sanding, I pulled the pin to give things time to cool down, and I'll come back to do the other forms another day. Here is the picture of where I'm at so far.
IMG_0365[1].jpg

wasting time looking at alternative techniques - 1 hour

Sanding 3/4 of the forms - 1.5 hours

Total time: 8 hours

Off to a good start.

So after a large delay due to putting my back out some time ago more progress has been made.

Cedar has been purchased and put through the thicknesser. About an hours work including resetting the blades.

Mobile Strongback has also been built although I had to make a second set of legs as the first ones were a little shaky. A ridicules 7 hours on this for something so simple.

Milling the strips will be next when I get some time



Total time spent 16 hours. And I really need to clean my bench off.


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