A) I've only read about half of this thread
B) I don't want to rain on your parade

However, as has been pointed out, cardboard is not a good boat building material.

Despite this, you need to look at your motivations here. If your goal is to have fun projects with the boy, making cardboard boats to play with and (on warm summer days) sink with, you've got plenty of fun project material here.

If your motivation is to have kayaks to go kayaking with your son, I would suggest a plywood frame and stringer kayak, like Tom Yost's designs at www.yostwerks.com.

You can reduce cost by lashing the frame together instead of epoxy. And if you skin with canvas, you can use the latex paint you already have to coat the skin.

This can still be a great project for you and your son, and then you can have very serviceable kayaks for minimal cost.

I am convinced that building plywood-frame-and-stringer, skin-on-frame kayaks is one of the most cost effective boat building techniques. And, once you've built one, you realize you can bang them out quite quickly. Or you can go very fancy with your frame. For example, I'm wondering if I should get a router table to make pretty bevelled edges to my plywood frames, or just bash together another boat quick and dirty...

So, long and short, have fun!

Brian

: 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