17 lb pirogue.......maybe

[jdupre']

John, from what I've read, the aluminum is epoxied and nailed onto the rails and takes the majority of the strain........sort of like the backing on a longbow. Hey, I'm no engineer but the guy that designed the boat is a ROCKET SCIENTIST! I'm hooking up my horse to THAT cart. :mrgreen:


Ok, Ron, I hit send and your response came up. I'm just going by what the designer did. Worked for him. I think the aluminum being stretched tight is the backbone of the design. I don't think the hull would be stiff enough without it. I'm thinking 12" or so of bend in the 14' length would not be a big strain.


Joey

 

[beekeeper]

The flashing will be cut to the shape of the side rails..... curves and all. From there, I don't thing it will encounter any tremendous strain to the final pirogue shape. My only concern is the rails being able to make the curve. Already committed ..... the curves are glued into the rails. We'll see.

Joey

I was thinking in terms of bending the side frames first and then covering them with the alu. Putting it on first would prevent the wrinkle problem I was thinking might happen.
Still don't know if you are home free, because you are changing the angle of the sides from the original design. What works vertical may change when flaired.
We will see. Sometimes "You have to go to know."

beekeeper

 

[Kayak Jack]

Skinning the boat with the fabric used on kayaks would be a light weight option too, I guess.

 

[jdupre']

Skinning the boat with the fabric used on kayaks would be a light weight option too, I guess.

NOOOooooooo, Jack! Don't put that idea in my head. :roll:

I'm pretty confident that the rails will bend like they're supposed to, even with the aluminum skin. (Famous last words. :mrgreen: ) The flashing is only .010" thick......about the thickness of 4 sheets of notebook paper. Think of a heavier gauge soft drink can.

Joey

 

[john the pom]

Then stretch that drink can when it's been fixed at both ends...

 

[jdupre']

Guys, I'm taking the designer at his word. He says he's built 30 boats like this. Very few on this board have built 30 boats total, much less 30 of one type.

As for the longbow comparison. This aluminum skin would place approx the same strain on the wood as just stringing a bow to a low brace height. Don't forget, these side panels will only be bent 11 or 12 inches over 14 feet. Really not much strain in my estimation.

Joey

 

[Kayak Jack]

Joey, turn off your computer and just go build your boat. More funner.

 

[jdupre']

Joey, turn off your computer and just go build your boat. More funner.

That's what I did, Jack. Got off of work early and put a finish coat of epoxy on one rail and a saturation coat and glass patches on the second one.

Next step is to attach the aluminum to the frames.

Joey

 

[Kayak Jack]

What's that strange, yellow light all over your grass? It's cloudy here today.

I'm thinking this is a critical step, now. Going to be interesting.

 

[jdupre']

Beautiful weather here , Jack. Two years ago when I built the Swamper I couldn't buy a day like this. Cold and rainy every day. I think I wore a coat to work every day that winter. Very unusual for down here. Last year winter was short. I think it was on a Tuesday......... in the morning. :lol:

Joey

 

[jdupre']

It's too late to turn back now. I got off of work at 3:00 and started attaching the skin on one of the rails. I tried cutting the alumunum with tin snips which worked , but left a serrated edge. The stuff is pretty thin and soft so I had the idea to try regular sewing scissors. Worked like a charm.

I mixed up a batch of thickened epoxy and applied it with a piping bag made from a freezer bag. I found out it's real hard to nail 5/8" nails while holding them with a forefinger and a thumb that's an inch wide. I tried needle nose pliers and that was better but slow and awkward. In the end, I was able to make a decent start.

Joey

 

[tx river rat]

Your driving nails with a shop hammer :lol: ,thats whats wrong!!
A little trick to use on that is a nail that is a couple inches long about the same size , prepunch your holes and into the wood just a little then you can insert tacks and it will hold them in place.
Ron

 

[jdupre']

Ron, my regular hammer just seemed like way overkill. The little machinist's hammer is just about right. I'm a little fumble fingered but I got into the groove after a while. I'll have a LOT of practice on this build. :roll: I like your tip, though.

As an aside, cutting the flashing with regular scissors I was struck by the fact that "This stuff is THIN!". I admit to having some second (and third) thoughts. Hey, nothing ventured......nothing gained.

Joey

 

[bcwetcoast]

Take a piece of cardboard (heavy paper stock not corrugated) and cut a slot in it. Insert the nail in the slot and use the cardboard to hold the nail to get it set.

You could also use an upholsterer's hammer, which has one end magnetized to hold tacks to get them started.

 

[Kayak Jack]

Joey, have you thought of nailing from the center out towards the ends? Lightly tack two opposing ends down, then start nailing at the center and work outwards. Pull the first two tacks as you approach them. May minimize wrinkling?

Won't do much for fumblefingerednessiosity, or getting lost in swamps, but may help with wrinkles (boat's, not yours). Of course, if the stuff is as thin as you say, maybe shrink it with a hair drier after it's nailed on! :wink:

 

[gbinga]

I found out it's real hard to nail 5/8" nails while holding them with a forefinger and a thumb that's an inch wide. I tried needle nose pliers and that was better but slow and awkward.

Warrington hammer. The flat side is used to start a short brad held between your fingertips. The skinny striking surface fits between your finger tips and taps the head of the brad. Of course there is still a limit to how short the brad can be, but this works better than a regular round face. Once you get the brad started, you reverse the hammer and use the round face to finish driving it. I have one of these, and it is definitely worth the space it takes up in the tool box.

http://www.leevalley.com/US/wood/page.aspx?p=32052&cat=1,53193&ap=1

 

[jdupre']

That side is done. I used Ron's pre-punch technique and it went smoothly. Completed side is about 6 lbs. ........12 lbs for two sides. That leaves 5lbs for the bottom ply, epoxy and a taped edges. Might make the 17lbs. but it won't hurt my feelings if it crowds 20. Still crazily lightweight for a 14' pirogue.

Joey

 

[jdupre']

Emphasis on "maybe". Houston, we might have a problem. I smeared a little excess thickened epoxy on a scrap of aluminum. Three days later, I could just peel it off in one sheet. :x I cleaned the metal with acetone before I attached the side. Last night I pushed against the glued alum. next to one of the uprights and it left the wood without much effort.

I think the nails will be enough to hold the sides on structurally, but not sure if the epoxy will seal the water out. Thought of using gutter seal caulking to seal the edges to salvage the build......or I might just salvage the rails and just use more of the Revolutionply for the sides.

Only thing I can think of is the designer used prepainted trim coil. Maybe the epoxy bonds to the paint which is factory bonded to the alum.

Ron, ain't boatbuilding fun?!! :roll:

Joey

 

[mike]

Try roughing up the aluminum with some coarse sandpaper, give the epoxy something to bond to.

Mike

 

[Kayak Jack]

Boat captain to passengers (in a deep, gravelly pilot-type voice): "Ahhhh ........ this is your captain speaking. I am no longer in the boat, as the sides have delaminated in that last wave. Those of you who can swim, please step to the right side of the boat, and calmly enter the water. The rest of you - thank you for riding in Cajun Canoes!" :wink: