As a cautionary note to those of you ambitious enough to try this yourself, know that it takes ALOT of time, effort, and planing. I managed to go from model and blueprint to full kayak in just 4 days, but know that I lost ALOT of sleep staying up late to laminate layers of cardboard layers, and there were several features that I simply did not have enough time to construct. I spent a few weeks in preparation scrounging around cardboard dumpsters looking for large, pristine (pristine is KEY as we learned) double layer (two layers thick) cardboard. You need ALOT of cardboard, the sheet used to make my kayak measured 6 ft wide by 10 feet long. With four layers to it, thats 240 square feet of cardboard!
Also, you need a large flat space on which to construct your plyboard.
Anyways, the great thing about making your own kayak is that you can make it to any specifications you want, and add any feature you want as well. My brother for instance, said he would have made a flat backed kayak so that he could put a trolling motor on his..... go nuts!
Also, you really REALLY need at least two people to build one of these, three is much better/easier. I was lucky enough to have the help of my Dad, my best friend, and my brother at times....
Enough disclaimer, lets get into the build process!
Step 1: Tools of the Cardboard Kayak Trade....
1 gallon of waterproof wood glue - 16-18$ @ Home Depot
paint roller - dollar store is fine, as cheap as you can get it, i got a nice combo pack at family dollar for 8$
paint tray - same as above
paint tray liners (3 or 4 is best) -same as above
good utility knife and lots of fresh sharp blades
skill saw with a fine toothed blade
140 or so bottles of beer, water, or any other small, relatively light weights
aprox. 300 sq feet of pressure sensitive adhesive backed vinyl (glorified contact paper)
The vinyl item is a tricky one, you MAY be able to find it by finding a local print shop that specializes in truck or vehicle wraps, and asking them if they have any bad, damaged or miss-printed rolls. It is just the waterproofing layer, so it just needs to be free of holes...
Also, i tested an alternative method of waterproofing, which is much more readily available. Helmsman Spar Polyurethane, make sure its for exterior and waterproof, i almost bought the interior stuff by mistake. Anyways, a couple LIBERAL coats of that (two is the absolute minimum, 3 or 4 is MUCH better) would work just fine. As i was pressured for time (i procrastinate, what can i say?) i opted for the vinyl, and as my father an I both work at a company that manufactures and designs billboard printers, coming by a few used rolls through a little dumpster diving was a piece of cake.
Oh yeah, How could i forget, you need CARDBOARD, AND LOTS OF IT!
Step 2: Make a Prototype, to Scale
Step 3: The Template
UPDATE: Okay, i finaly got a PDF version of the template done up, and it should be attached to this step. It's diemensioned and has fold lines with the degree the fold requires indicated. Ovbiously, you don't need to bend the folds to excatly 45.12 degress, just if you are going to make this kayak out of say, sheet metal, it's important to have that sort of acuracy. Sorry it took me so long to get the template up, I had to learn how to use the Sheet metal function in SolidWorks, and then model it.... time consuming to say the least. Anyways, would love to hear if anyone ends up building it.
Step 4: First You Need a Large Flat Work Space....
Step 5: Start Cutting Cardboard Like Your Life Depended on It!
MAKE SURE THE GRAIN IN THE LAYER IS ALL GOING THE SAME WAY! This is crucial, the entire design hinges upon this one element. Cardboard, has a grain direction to it, and each layer must have all the sheets that make it up orientated so that it is all going in the same direction, with each layer having the grain rotated 90 degrees from the one below it.
For a visual break down of the grain orientation of each layer, look at the last few photos. please understand that I did the grain visual break down on a model of each layer, and that in reality, each of your layers will be 6ft by 10ft if you follow my plan to the letter....
Step 6: Lay Out the First Layer
Step 7: Now the Fun, and Most Crucial Step; LAMINATING!
Once you've got your glue on, start sticking on your sheets of cardboard. we found it was helpful to layout the layer first, make a bunch of reference marks, in terms of how each should line up with the other, and then laminate. That way when you go to put down a piece of cardboard, you can look at the one you put down right before it and go, oh i see, that one lines up with this line, so it must go here. Very simple trick, yet saves alot of time and confusion. Press the cardboard firmly into place, but not too hard, as we don't want to dent the sheet and ruin it's structural integrity.
Step 8: Weighting, and Waiting.....
Leave each layer to dry overnight, and then cut a new layer (with the grain going 90degrees different from the previous layer) and repeat until you have a sheet that is four layers thick. since i highly recommend using double layered cardboard, it's technically 8 layers thick, but whatever. the point is make it beefy, you don't want to be putting your foot through the bottom of your kayak cause you were lazy and only did a few layers......
Step 9: Mark, Cut and Laminate, or Waterproof.
waterproofing can also be done by applying SEVERAL (as in more than one) liberal coats of helmsman spar polyurethane.
Step 10: Fold It All Up, and Laminate the Seams
Step 11: ENJOY YOUR ONE OF a KIND CARDBOARD KAYAK!!!!
The kayak weighs only 35lbs. I measured by standing on a scale, then holding the kayak, and then subtracting my weight, so it may be off by a few pounds, but it is still super light.