strip canoe building

strip canoe building

Post by Bob Smi » Sun, 10 Apr 1994 02:02:28



: I am about to buld my first cedar strip canoe, and I would like whatever
: advice those of you who have done it before have.  I have read both
: "Canoecraft" by Ted Moores, and Gil Gilpatrick's book, and they both come
: down in favor of epxy over polyester, although several local builders in
: the area (Twin Cities, MN) have told me that polyester is fine, about
: 1/3 the price, and a lot easier to work with.  Opinions, please!  This is
: an important issue, as it is by far the most expensive part of the canoe,
: and yet I want something that will last--the canoe will be, after all, a
: wedding gift to my bride!  
:    The second issue involves F-glass.  I've heard conflicting things about
: the weight to use, hearing everything from 4 - 7 ounce.  Should the glass
: be doubled all over, just on the bottom, or not at all?
:    Third, what to use for the trim?  I've heard that white ash is best,
: but I've had a devil of a time finding it in anything longer than 12 foot
: lengths.  Is a scarf joint adequate to join it?  Are there other
: reasonable alternatives?
:    Fourth, has anyone used the bead and cove method advocated by Moores?
: Is it worth the trouble I envision having with it?  
:    Fifth, how serious an issue is temperature for epoxy curing.  We've
: been having some ridiculous weather up here, and I'm going to be curing
: probably the third weekend in April.  If the temp drops below 60 degrees,
: does it ruin or cloud the epoxy?
:    Finally, what epoxy to use, if I go that route?  The 205 and 206
: hardeners in the WEST SYSTEM are "not for clear finishes"  but I thought
: that this is what has been used for strip canoes all along.  Has anyone
: used the newer, more expensive 207, which supposedly dries very clear?  
:    Thanks much for any replies, either over the net or to me personally!  
: Dave Olson

--

                           I've got a plan so cunning,
               you could stick a tail on it and call it a weasel

 
 
 

strip canoe building

Post by Bob Smi » Sun, 10 Apr 1994 02:08:18


:  I am about to buld my first cedar strip canoe, and I would like whatever :
advice those of you who have done it before have.  I have read both :
"Canoecraft" by Ted Moores, and Gil Gilpatrick's book, and they both come :
down in favor of epxy over polyester, although several local builders in :  the
area (Twin Cities, MN) have told me that polyester is fine, about

I have tried several epoxys and polyesters.  There are benefits and
problems with each.

Epoxies:  West System is the most popular of the epoxies, however at $55 to $65
a gallon, it is the most expensive that I have used.  I have also tried System
3's epoxy.  It runs around $45 a gallon.  System 3 is a 2:1 mix and West System
is a 5:1 mix.  I like epoxy becaus of it's solid feel when done, and the
'warmth' it adds to the color of the cedar (the epoxy is the same tint as spar
varnish), and I can tolerate the smell better.  How ever there is an accumulated
alergic reaction with these epoxies, so I wear elbow length gloves, and a smock
when working with epoxy.

Polyesters:  I've tried three different polyesters so far.  The first kind uses
cobalt as part of the catalyst.  This causes a 'Haze' color to the poly when
done.  This is like looking through a hazy sky at the far shore of a lake.  It
diminishes the color, and figure of the wood used to build the hull.  I've also
tried 'Casting polyester', This poly does not use cobalt as part of the
catalyst, and creates a resin that is as clear as pure water.  This is also
stiffer than regular poly, and has a similar 'feel' to the hull as epoxy.  The
last poly is one that I know the least about (not that I know a lot to begin
with).  It is similar to casting poly, in that it also does not use cobalt, but
it is not called a casting resin.  It is also clear as water, and I have been
told that it's proporties are between standard poly and epoxy.  As far as cost,
standard poly costs $18 a gallon including MEK catalyst, Casting poly cost $36 a
gallon including a non toxic catalyst, and the last poly is around $22 a gallon
including catalyst.

As far as workability, Poly is much thinner than epoxy, and can be rolled on
using a molehair roller.  I prefer epoxy because I like to use a bondo squeegee,
and epoxy is slower (it doesn't run).

: 1/3 the price, and a lot easier to work with.  Opinions, please!  This is
: an important issue, as it is by far the most expensive part of the canoe,
: and yet I want something that will last--the canoe will be, after all, a
: wedding gift to my bride!  
:    The second issue involves F-glass.  I've heard conflicting things about
: the weight to use, hearing everything from 4 - 7 ounce.  Should the glass
: be doubled all over, just on the bottom, or not at all?

I've built canoes with single layer, double layers, and doubled only on the
bottom.  I would only double it on the bottom when I expect to be dragging
it over a lot of rocks.

As far as the weight to use, for a flat-water (ie BWCAW) solo canoe that I
intend to baby, I use 3/16" thick strips, with 4oz glass cloth, and use system 3
epoxy, or a hard clear poly.  For a tandem I would increase the cloth to 6oz on
the out side and 4oz on the inside.  For a rough-use solo I would use 6oz on the
outside and 4oz on the inside, and for a tandem i would use 6oz in and out, and
if it is REALLY rough I would double the bottom.  I just finnished a 16.5'
Merlin solo in cedar, 3/16" strips, system 3 epoxy, and 4oz cloth, and cheap
(inexpensive) mahogany trim, microdecks and seat weighed 28.5lb.

:    Third, what to use for the trim?  I've heard that white ash is best,
: but I've had a devil of a time finding it in anything longer than 12 foot
: lengths.  Is a scarf joint adequate to join it?  Are there other
: reasonable alternatives?

I've used oak, mahogany, butternut, cherry, ash, and cedar. Ash will generally
give you the best strength per weight. Oak will give the best strength per
dimention (more delicate looking trim), butternut, and cherry when oiled,
provide a nice contrast in tone (I prefer butternut over cherry) and I use
mahogany just because I can get it in 20' lengths, and it weighs very little.

:    Fourth, has anyone used the bead and cove method advocated by Moores?
: Is it worth the trouble I envision having with it?  

Unless your strips are  near perfect, I wouldn't recommend using bead and cove.
It does eliminate 'most' light leaks (areas where you can see light through the
hull), but it will not eliminate all of them.  It does make the hull slightly
stringer durring the sanding phase, but I find the extra work of coving, and
beading, not worth the benifits.

:    Fifth, how serious an issue is temperature for epoxy curing.  We've
: been having some ridiculous weather up here, and I'm going to be curing
: probably the third weekend in April.  If the temp drops below 60 degrees,
: does it ruin or cloud the epoxy?

Temp is not as big an issue with epoxy as humidity.  High humidity will cloud
your epoxy. you epoxy will cure slowly when the temp drops, however if you heat
the epoxy bottles in warm water, it will eliminate most of the delay in cure
time.

:    Finally, what epoxy to use, if I go that route?  The 205 and 206
: hardeners in the WEST SYSTEM are "not for clear finishes"  but I thought
: that this is what has been used for strip canoes all along.  Has anyone
: used the newer, more expensive 207, which supposedly dries very clear?  

I don't have any information on what West System epoxies I have used, since
I haven't used West in several years. But I remember that I used the cooler
weather hardener, because it is cool here in Mn. in the spring.

:    Thanks much for any replies, either over the net or to me personally!  
: Dave Olson

--
Bob Smith
                           I've got a plan so cunning,
               you could stick a tail on it and call it a weasel

--

            I've got a plan so cunning,  
  you could stick a tail on it and call it a weasel

 
 
 

strip canoe building

Post by LanceR66 » Sun, 10 Apr 1994 13:59:01


Quote:
Olson) writes:

David:

Go with the epoxy. It is easier to work with, isn't as volatile and is more
forgiving. In other words, if you***up a little, you don't ruin all the
fiberglass. Of course, if you***up a lot, start over. I've used an epoxy
called System Three. I can't remember who makes it, but we ordered it from the
Flounder Bay Boat Works in Anacortes, Wash. It is more expensive, but worth it.
After all, you're building something that will last a very long time and look
pretty cool on the water, too.

 We (two friends and I) are using a book by David Hazen called "A Wood
***s Guide to Canoe Building. It was written in the 1970s but still sells
like hot cakes today. A classic.

Wood: We are using Sitka spruce, which is pretty common in 18 and 20-foot
lengths. We bought it pre-cut, with the bead and cove already cut as well.
Instead of staples, we're gluing the strips together using a hot glue gun.
Spruce is a lot lighter in color, which I prefer.

Trim: We're using several hardwoods. We put a single strip of black walnut in
the bow and stern plates, as well as the teardrop-shaped ballast tank covers.
We're using spruce for the inside gunwale, mahogany for the outer gunwale and
black walnut for the spacers. It sounds like a lot of different wood, but it
does look cool. The thwarts and seats are made from mahogany, with black walnut
inlay around the caned seat.

Lance Robertson

 
 
 

strip canoe building

Post by Guillem » Mon, 11 Apr 1994 05:46:04

Quote:
>I am about to buld my first cedar strip canoe, and I would like whatever
>advice those of you who have done it before have.  I have read both
>"Canoecraft" by Ted Moores, and Gil Gilpatrick's book, and they both come
>down in favor of epxy over polyester, although several local builders in
>the area (Twin Cities, MN) have told me that polyester is fine, about
>1/3 the price, and a lot easier to work with....

Epoxy is worth it. It will stay looking good longer, is stronger, you end up
using less resin than polyester. Epoxy is just better all around. Except for
being somewhat touchy about mixing ratio I found epoxy to be easier to use. It
doesn't cure so fast giving you time to work. It does not smell as bad. (This
does not imply it is less dangerous, you just smell better when you die)

Quote:
>   The second issue involves F-glass.  I've heard conflicting things about
>the weight to use, hearing everything from 4 - 7 ounce.  Should the glass
>be doubled all over, just on the bottom, or not at all?

How much glass to use depends on the intended use and how light you want the
boat. 2 layers of 4oz on the bottom 1 layer elsewhere should suffice for most
uses. One layer 4oz for careful use. 2 layers 10oz on bottom 1 layer elsewhere
is plenty for abusive use.

Quote:
>   Third, what to use for the trim?  I've heard that white ash is best,
>but I've had a devil of a time finding it in anything longer than 12 foot
>lengths.  Is a scarf joint adequate to join it?  Are there other
>reasonable alternatives?

Any hardwood will do. Scarfing the ash is probably your best bet.

Quote:
>   Fourth, has anyone used the bead and cove method advocated by Moores?
>Is it worth the trouble I envision having with it?  

Cove and bead makes for tighter seams. This is primarily cosmetic. A few small
gaps are not a problem structurally an only you will see them. Save some effort
don't cove and bead.

Quote:
>   Fifth, how serious an issue is temperature for epoxy curing.  We've
>been having some ridiculous weather up here, and I'm going to be curing
>probably the third weekend in April.  If the temp drops below 60 degrees,
>does it ruin or cloud the epoxy?

You can purchase different hardeners for different temps. A "medium" cure
should suffice for spring/summer projects. I now steer clear of fast cures
after some clouding problems. The clouding appear after a couple months. There
appeared to be a bonding problem with the glass.

Quote:
>   Finally, what epoxy to use, if I go that route?  The 205 and 206
>hardeners in the WEST SYSTEM are "not for clear finishes"  but I thought
>that this is what has been used for strip canoes all along.  Has anyone
>used the newer, more expensive 207, which supposedly dries very clear?  

I use System 3 epoxy. It is somewhat cheaper and seems to be every bit as good
as WEST. System 3 Clear Coat works well.

Nick Schade
Guillemot Kayaks
Oakdale, CT

 
 
 

strip canoe building

Post by Jim Colt » Wed, 13 Apr 1994 00:23:12



Quote:
>many useful details about canoe building deleted for brefity ....

>the out side and 4oz on the inside.  For a rough-use solo I would use 6oz on   e
>outside and 4oz on the inside, and for a tandem i would use 6oz in and out, &
>if it is REALLY rough I would double the bottom.

This advise is good when 'rough-use' means abrasion.  When it means slamming
into rocks like what might happen in whitewater canoeing, then you need to
double the inside.  The inside skin of a *** gets stretched when the
hull is pushed in.  In that situation the strength of the hull is determined by
the strength of the inside skin.

Quote:
> more detail deleted ...

>:    Fourth, has anyone used the bead and cove method advocated by Moores?
>: Is it worth the trouble I envision having with it?

>Unless your strips are  near perfect, I wouldn't recommend using bead and cove.

Yes, you do want nice uniformly thick strips when you cove&bead.  But then
you want nice uniform strips anyway.  It really is a mattter of personal
choice and skills.  I have built two with straight strips, helped build one
with cove&bead.  It took about an hour to make a tall fence for the router
table and to make two feather boards.  Then it took about four hours to
cove&bead 60 strips.  That time can be halved if you can setup two routers
and do both cove&bead in one pass.  I am a bit of a klutz with hand tools
so it worked out very nice to carefully do the router setup, spend the four
hours and then not worry about beveling the strips, even in the tightest
curves (beveling is not really needed where the curves are not tight.
Cove&bead also makes it much easier to keep the strips lined up nicely.  Saves
a little time planing and sanding.

Quote:
>Temp is not as big an issue with epoxy as humidity.  High humidity will cloud
>your epoxy. the epoxy will cure slowly when the temp drops, however if you heat
>the epoxy bottles in warm water, it will eliminate most of the delay in cure
>time.

I beg to differ here.  Heating the resin does make it less viscous and will
speed up the cure if you can maintain the temperature.  However, long before
the resin cures, it assumes a temperature similar to the air temp and the temp
of the wooden hull.  Air/hull temperature is important.

Quote:
>--
>Bob Smith

Jim Colten
 
 
 

strip canoe building

Post by Bob Smi » Wed, 13 Apr 1994 03:45:40



:  
: >many useful details about canoe building deleted for brefity ....
: >
: >the out side and 4oz on the inside.  For a rough-use solo I would use 6oz on   e
: >outside and 4oz on the inside, and for a tandem i would use 6oz in and out, &
: >if it is REALLY rough I would double the bottom.
:  
: This advise is good when 'rough-use' means abrasion.  When it means slamming
: into rocks like what might happen in whitewater canoeing, then you need to
: double the inside.  The inside skin of a *** gets stretched when the
: hull is pushed in.  In that situation the strength of the hull is determined by
: the strength of the inside skin.
:  
: > more detail deleted ...
: >
: >:    Fourth, has anyone used the bead and cove method advocated by Moores?
: >: Is it worth the trouble I envision having with it?
: >
: >Unless your strips are  near perfect, I wouldn't recommend using bead and cove.
: Yes, you do want nice uniformly thick strips when you cove&bead.  But then
: you want nice uniform strips anyway.  It really is a mattter of personal
: choice and skills.  I have built two with straight strips, helped build one
: with cove&bead.  It took about an hour to make a tall fence for the router
: table and to make two feather boards.  Then it took about four hours to
: cove&bead 60 strips.  That time can be halved if you can setup two routers
: and do both cove&bead in one pass.  I am a bit of a klutz with hand tools
: so it worked out very nice to carefully do the router setup, spend the four
: hours and then not worry about beveling the strips, even in the tightest
: curves (beveling is not really needed where the curves are not tight.
: Cove&bead also makes it much easier to keep the strips lined up nicely.  Saves
: a little time planing and sanding.
:  
: >Temp is not as big an issue with epoxy as humidity.  High humidity will cloud
: >your epoxy. the epoxy will cure slowly when the temp drops, however if you heat
: >the epoxy bottles in warm water, it will eliminate most of the delay in cure
: >time.
:  
: I beg to differ here.  Heating the resin does make it less viscous and will
: speed up the cure if you can maintain the temperature.  However, long before
: the resin cures, it assumes a temperature similar to the air temp and the temp
: of the wooden hull.  Air/hull temperature is important.
:  
: >--
: >Bob Smith
:  
:  
: Jim Colten

--

                           I've got a plan so cunning,
               you could stick a tail on it and call it a weasel

 
 
 

strip canoe building

Post by Bob Smi » Wed, 13 Apr 1994 03:57:35



: >Temp is not as big an issue with epoxy as humidity.  High humidity will cloud
: >your epoxy. the epoxy will cure slowly when the temp drops, however if you heat
: >the epoxy bottles in warm water, it will eliminate most of the delay in cure
: >time.
:  
: I beg to differ here.  Heating the resin does make it less viscous and will
: speed up the cure if you can maintain the temperature.  However, long before
: the resin cures, it assumes a temperature similar to the air temp and the temp
: of the wooden hull.  Air/hull temperature is important.
:  
:  
: Jim Colten

All I can say is that pre-heating works!  The explanation given to me was that
when the air temp is cool/cold the cure time is very long.  Pre-heating shortens
this cure time by shortening the pot-life of the epoxy. Once the resin is mixed
with the hardener it creates heat, the more heat, the shorter the pot-life, so
pre-heating is simmilar to useing large amounts of resin, and hardener without
having to worry about trying to use all that extra epoxy before it 'kicks over'

Bob Smith
--

                           I've got a plan so cunning,
               you could stick a tail on it and call it a weasel