Pakyak Frame F.A.Q.
1. Why did you choose Baltic birch plywood?
2. I can't find the sizes of the
hardware pieces needed to put together the stringers and other braces.
3. About the center brace, am I right that the thwart has no locking
function for the underlying bottom stringers?
4. Section 2, Parts Finishing (Gunwale): Hinge assembly: Why do the
angle pieces have to have 2 round notches?
5. There are no washers between stringers. Are the screws not firmly tightened ?
6. I was just wondering how did you use
your drill press to round the edges of the wooden strips.
7. Any suggestions where to find the 9 ply Baltic
birch. Home Depot seems to have only 5 ply Birch.
8. Could the frame be built with bamboo or aluminum tubes instead of plywood?
9. I couldn't find any referance
to the spacing between the four stringers in the very front and back of
the boat.
10. The Gunwale hinges are drilled with a 3/16" hole. Should I use 10-32 machine screws?
11. What did you use to cut the angle braces? I am using a hack saw.
12. Why plywood? Why not something like spruce or Douglas fir?
13. What type of aluminum did you use?
- I was curious as to whether Baltic birch plywood was just your wood of
choice or if this wood was chosen for another reason. I am currently
trying to find a supplier near where I live. Will marine grade
plywood work also? What about ½" thick oak or other hardwood?
Just about any plywood will work, I think. I like the Baltic birch
because it is hardwood, 9 ply cabinet grade, tougher than fir
plywood and with fewer voids. The trouble you might have if you
use straight hardwood is that the ends may split out from the
screw holes. Plywood gives you those cross plies on the ends
that prevent this.
The Baltic Birch plywood and all the other materials you will need
should be available locally, if you ask around a bit. So far that's
been true for me and everyone else who has built one.
- I have gone through
the plans more than a few times and I can't find the sizes of the
hardware pieces needed to put together the stringers and other braces.
I know that the machine screws are size 10-32 but what about the
lengths? The ends of the kayak are put together with 3" bolts (?)
(I'm still using the older prototype design without the updates) but
I'm unsure if the other bolts are 1.25" or 1.5"?
Yes, you'll want to get some different lengths.
For the brace parts you can generally use 3/4" because they go
through 1/2" of plywood and 1/8" of aluminum.
For the stringers you generally need 1 1/4" lengths because they go
through 2 layers of plywood plus 1/8" aluminum.
At the center braces 1" works.
You'll see as you get into it what is needed where.
- About the center brace, am I right that the thwart has no locking
function for the underlying bottom stringers? It just carries side
pressure, right?
Yes, you are right that the thwart has no locking function for the
bottom stringers, just helps hold their spacing against side pressure
from the water.
- Section 2, Parts Finishing (Gunwale): Hinge assembly: Why do the
angle pieces have to have 2 round notches?
The notches allow the skin to fold without pinching it.
- There are no washers between stringers. Are the screws not firmly tightened ?
If so, isn't there a lot of friction between stringers ruining the varnish?
You are absolutely right about this. Washers would be a good idea. But
you might have to countersink the stringers if the washers are too thick,
for the frame to fold as tight as it should. So watch out for that.
- I was just wondering how did you use
your drill press to round the edges of the wooden strips. I
got a drill press but can't figure out how to setup a jig to
do this.
First I made a little table and fence that I could clamp
on top of my drill press vise, with a gap in the fence for a 1/4-round
router bit. Then I positioned the table under the bit so when I slide
the strips along the fence the edge goes under the router blade. I
also have my drill press set up so I can adjust the drill down, rather
than having to move the table up to the bit. I do this by moving the
nut that sets the drill depth from above the stop to below it, so the
stop keeps it from going up. Kind of a jury-rig, but it works for me.
I've been thinking of modifying my fence so the strips fit into a slot
and are held down. That would help prevent the nicks I get when I
accidentally let them lift up against the router. Anyway, I hope you
get the idea.
- Any suggestions where to find the 9 ply Baltic
birch. Home Depot seems to have only 5 ply Birch.
Home Depot's 5-ply birch might work okay if there are no voids.
That's the main reason I suggest the Baltic Birch. The price on the
Finnish 9-ply does sound like a lot, but there are various grades
and that is probably top quality. Actually any good quality plywood
with no voids would do.
If they don't know "Baltic Birch" ask for "cabinet grade" plywood.
Here's an on-line site where you can get it if all else fails.
http://woodbymail.com/balticbirch.html
- Could the frame be built with bamboo or aluminum tubes instead of plywood?
The idea of using bamboo for the stringers is interesting, but it
would be an experiment. I'm afraid that in small enough diameter
to fit the design it would be too flexible.
Similarly with aluminum tubing, it would have to be 1/2 inch
diameter to fit the design, and that might not be strong enough. I
know that aluminum extrusions are made in 1" x 1/2" rectangular
shape, and that could be a direct substitute for the plywood
stringers. But I haven't found a distributor that will sell that size in
small quantities. Maybe you would have better luck with that.
Anyway, I still use plywood.
- I looked all through your notes and couldn't find any referance
to the spacing between the four stringers in the very front and back of
the boat. In the plans it shows a space between the middle two. You call
for a 3" roundhead screw which leaves plenty of room.
The space you asked about needs to be wide enough for a stringer
to fold into it, so it needs to be just over 1/2 inch wide. To make
the spacers you can use something as simple as the body of an old Bic pen.
- The Gunwale hinges are drilled with a 3/16" hole. My rivets seem too
small. Does this mean I am to fasten them with the 10-32 machine screws?
Yes, these hinges need to be pretty strong, so hollow pop rivets
won't do the job.
- What did you use to cut the angle braces? I am using a hack saw.
A hack saw is fine, although I've used a cutting wheel for some of
the work.
- Why plywood? Why not something like spruce or Douglas fir?
I like plywood for two reasons. I can rip a sheet into the 1" strips I
use with little waste, and the cross plys help keep the end holes
from breaking out, as can tend to happen with normal wood.
- What type of aluminum did you use? Or is this just generic
home improvement store grade?
I use the cheapest generic hardware grade I can find. I even try to
avoid anodized because it doubles the expense. |