: Scout leader with no money, lots of Styrofoam and cardboard... any
: ideas on how to build a durable cardboard kayaks for 10 year old
: son and 280 lb man. Could the kayak for my son be a prototype
: for the big boat? I really want to use this kayak for exercise
: on local South Carolina lake.

: I have dozens of large Styrofoam (2" thick) coolers in white
: cardboard boxes. I can laminate cardboard on both sides of the
: cardboard. Would use waterproof TiteBond III to glue them
: together, or do i have to use rubber cement? I don't have a
: workshop so I need to create components and assemble it under a
: shed.

: I have seen the kayak plans for $40 online. I want a little better
: design; something like the S&G Guillemot, or am I
: dreaming??!!!

: I am open to suggestions, comments and advice

Forget the cardboard: by now you have enough information that it is dangerous and would cost more to make it useable than to buy alternative materials. Cardboard boat races are popular precisely because it is so difficult and so much fun to watch them sink. I'm assuming you want a useful boat as cheap as possible. So think outside the (cardboard) box!

That leaves Styrofoam, the TiteBond III and rubber cement that you either have or are prepared to buy, and whatever you can scrounge. The cheapest boat type is skin-on-frame. For a SOF you will need bulkheads and stringers to make the frame and a reasonably strong fabric and paint for the skin.

Carefully made and reinforced frames cut from Styrofoam will work, though recycled ply is better.

Since you have access to power tools then stringers can be cut from any more-or-less straight-grained wood. To get longer lengths scarf pieces together: Titebond III is supposed to be waterproof but few boat builders trust it below the waterline: if you use it, use a low angle scarf such as 12" and reinforce the joint with binding twine. The twine will also fasten the bulkheads and stringers; there are plenty of free plans around the Internet and boating publications for how to do this. paint the frame thoroughly before adding the skin to protect the joints and bindings: a bit of water will slosh around no matter how watertight you make the skin and you don't want the frame disassembling itself far from shore. also, always dry a boat made from below-standard materials to prevent deterioration, between trips.

That leaves the skin: canvas is fine - as a scout leader you may be able to find an old tent that can be recycled, or a tarp will do the job. The tent canvas will need additional waterproofing but the tarp will not. Tarp can be attached using double-sided OUTDOOR carpet tape, sticks like anything and will resist saturation for months or probably years: just keep an eye on the seams. A good quality duct tape will add reinforcement over the seams. Rubber cement has been used in the past but is not always satisfactory and may be hard to get these days. Check with other troops. There are other useable skin materials out there, get an article in your local paper to attract support and interest. Some fabrics will already be waterproof and others will need treatment, after attaching to the frame. Tyvek (try a building site for left-overs) is an example. See what your local draper or uphosterer has - I got some really tough nylon left over from a commercial job once.

Returning to the stringers, if the old tent still has its wood or aluminum poles these can be adapted for the most important longitudinal boat parts which are the gunwales and the keel. And of course bamboo is fine if you know how to use it: Google "bamboo bending" or somesuch, there are some sites that show how craftsmen in India and other places straighten it and form it to make furniture: it doesn't look difficult.

Good luck, and for God's sake be careful on the water.