Guys I apprciate all the info. All this info is for my 3rd one I'm fixing to start. Still finishing the 2nd flat bottom. The 3rd will be a UJ Piroge. I have found a place I can get 16' rough cut ceder, pine, or cypress. I would like to plane it down to 1/8" or so and build the Piroge out of 2" strips and no epoxy. In my mind the wood would be simi smooth but would age and look "cool". If I can't do it in strips I would just plane it down to 1/8" and use a 10" strip for each side and either a plywood bottom or glue 10" strips together. I wouldn't have to scarf for length which would cut down on seams. Does my idea sound feasable? And would I use "glue" to seal the bottom to the sides?
plywood choices
- Thread starter 1fast68
- Start date
Not to me. I don't think that 1/8 inch wood without fiberglass and resin would be nearly strong enough.1fast68 said:
Jimmy
don't think 1/8" thick solid wood only of any species is strong enough for for a boat. Especially if you want it to "weather" 'cause it'll likely stress crack as it weathers and goes through wet and dry cycles.
An old boat builder told me that a 12" wide cypress board will move about 1/2" going from dry to soaking wet. Old cypress boats were built and kept in the water so they never dried out and never leaked. Our challenge today is to build a cypress boat that is tight when it's dry and to keep the wood dry so it doesn't move. That's why you'd paint, varnish or epoxy - to keep water away from the wood
Folks I know that have boats that are mostly on the dry and look old and weathered coat the outside and let the inside weather. No coating on the inside lets it weather and turn gray and the coating on the outside keeps the wood from soaking up water when it's being used.
An old boat builder told me that a 12" wide cypress board will move about 1/2" going from dry to soaking wet. Old cypress boats were built and kept in the water so they never dried out and never leaked. Our challenge today is to build a cypress boat that is tight when it's dry and to keep the wood dry so it doesn't move. That's why you'd paint, varnish or epoxy - to keep water away from the wood
Folks I know that have boats that are mostly on the dry and look old and weathered coat the outside and let the inside weather. No coating on the inside lets it weather and turn gray and the coating on the outside keeps the wood from soaking up water when it's being used.
ok, thanks guys. I just wanted to see if my thoughts were possible. I guess I'll just have to epoxy it 
1/8 plywood is way stronger than 1/8 plank
other folks here have lots of experience building with 1/8" plywood and epoxy/glass
not sure that translates directly to 1/8" plank and epoxy/glass
I believe that folks that build strip canoes, etc. use 3/16 or 1/4 thick strips then encapsulate with epoxy/glass. Haven't heard of anyone using 1/8 strips
you might be plowing new ground here
other folks here have lots of experience building with 1/8" plywood and epoxy/glass
not sure that translates directly to 1/8" plank and epoxy/glass
I believe that folks that build strip canoes, etc. use 3/16 or 1/4 thick strips then encapsulate with epoxy/glass. Haven't heard of anyone using 1/8 strips
you might be plowing new ground here
Gilppatrick recommends 1/4 strips, completely encapsulated in epoxy and fibreglass. As do most other strip build designers.
I know that a 12' 1x4 pine board weighs 7lbs. So if I plane cypress down to 1/4" strips and use 10" sides and the weight is close to that of pine. I should be able to build a 14' pirogue for under 30lbs? Does that sound right?
a quick check of a few internet sites show density of cypress to be .4 to .5
compared with water
a cubic foot of cypress would weigh between 25 and 31 pounds
a cubic foot is 12 board feet
therefore a board foot of cypress would weigh between about 2 and 2.6 pounds.
one board foot at 1" thick is one square foot, so a board foot at 1/4" would be 4 square feet
don't know the details of your design but a 12' pirogue needs about 40 square feet for sides and bottom
40 square feet at 1/4" thick is about 10 board feet, which means 20 to 26 pounds just for the wood for sides and bottom. Time you add seats, trim, glass and epoxy you'll be over 30lb.
compared with water
a cubic foot of cypress would weigh between 25 and 31 pounds
a cubic foot is 12 board feet
therefore a board foot of cypress would weigh between about 2 and 2.6 pounds.
one board foot at 1" thick is one square foot, so a board foot at 1/4" would be 4 square feet
don't know the details of your design but a 12' pirogue needs about 40 square feet for sides and bottom
40 square feet at 1/4" thick is about 10 board feet, which means 20 to 26 pounds just for the wood for sides and bottom. Time you add seats, trim, glass and epoxy you'll be over 30lb.
1Fast68, another consideration here than may have slipped past you is that the sides are NOT a square plank. The longitudinal edges are curved.
If you make a 10" side from one piece of wood with square corners, it's going to have to start out wider than a finished 10".
If you already knew this, then I'll quietly go back to my glass of scotch. (In fact, I think I'll do that no matter what you knew or didn't.)
If you make a 10" side from one piece of wood with square corners, it's going to have to start out wider than a finished 10".
If you already knew this, then I'll quietly go back to my glass of scotch. (In fact, I think I'll do that no matter what you knew or didn't.)
Jack, I didn't know that, the UJ plans I have shows the sides the same thickness all the way down with xx degree of angle cut on each end.
On the UJ pirogue the long edges are straight and parallel.
http://www.unclejohns.com/boat/plans/p12build.pdf
Jimmy
http://www.unclejohns.com/boat/plans/p12build.pdf
Jimmy
Kayak Jack said:
It does have rocker in it about 2 inches. The end pieces and the ribs cause the rocker by the angle that is on the outside of them. Not only the angle from the boat the angle that the outside of the ribs is trimmed/cut at.
Fasting the side panels at one end is no problem and doing one side at the other end is sort of fun :roll: but that last one is a sucker when doing it yourself.
Chuck.
Yeah, I didn't consider how difficult that second end of a pirogue would be!
the first went so well, I went ahead and epoxied that last stem joint, started my the four screws, and casually reached for the side. I mean how difficult can it be to bend a ten inch piece of quarter inch ply, sixteen feet long?
The stem and the side were nowhere near one another, when the side with the stem already attached slid off the saw horse and the fight was on!
I wrestled the assembly all over the yard, epoxied my screw gun, hair, clothing, and saw horses. I ripped off the last pair of latex gloves I will ever wear on a build, finally pinning it against an elm tree, jamming a short 1X10 amidships, and succeeded in getting the screws driven home.
Speak of your learning experiance!
I will have some help on the next one, or rig some way of immobilizing that second end. I might consider polyurethane glue instead of the epoxy,And pneumatic "T" nails insted of the drywall screws.
Pirogues must learn; I will win EVERY time! (Given enough time.)
the first went so well, I went ahead and epoxied that last stem joint, started my the four screws, and casually reached for the side. I mean how difficult can it be to bend a ten inch piece of quarter inch ply, sixteen feet long?
The stem and the side were nowhere near one another, when the side with the stem already attached slid off the saw horse and the fight was on!
I wrestled the assembly all over the yard, epoxied my screw gun, hair, clothing, and saw horses. I ripped off the last pair of latex gloves I will ever wear on a build, finally pinning it against an elm tree, jamming a short 1X10 amidships, and succeeded in getting the screws driven home.
Speak of your learning experiance!
I will have some help on the next one, or rig some way of immobilizing that second end. I might consider polyurethane glue instead of the epoxy,And pneumatic "T" nails insted of the drywall screws.
Pirogues must learn; I will win EVERY time! (Given enough time.)
next time make a couple of jigs out of scraps to bend the sides around as you close up the end
if you don't have clamps, bring the two ends together with rope or ratchet straps
i bend in 3/4" planks this way, so 1/4" ply is doable
if you don't have clamps, bring the two ends together with rope or ratchet straps
i bend in 3/4" planks this way, so 1/4" ply is doable
Jimsong,
As long as you win round 2 with that boat - you're OK.
BTW - don't stop wearing latex gloves when using epoxy. Keep protecting your hands.
As long as you win round 2 with that boat - you're OK.
BTW - don't stop wearing latex gloves when using epoxy. Keep protecting your hands.
the thing i picked up was to plane down a bd to 1/4". that glass stuff has a place, its just not my thing. but i take a board and plane it down to 1 inch or 7/8, (3/4 store bought) and table saw 1/4 strips then the bead thing. have a nice day, later keith