I'm about to begin my first kayak construction project, a folding 16' LOA 3/4" .049 aluminum tubing & 1/2" plywood.

Has anyone used TIG welding to aluminum bows and sterns instead of HDPE or tying aluminum? Seems to me that I could flatten the tubing ends, weld and then grind for a sharp, clean fit. I would plan on applying a liberal coat of penetrating epoxy to the plywood for durability and rot-proofing...

Also, how about using a cheap 4x16 canvas drop cloth (such as Home Depot carries) and painting it for a few trial runs. Seems like it would be cheap and easy and one could make final adjustments to the frame according to how it rides, then make up the final skin with the usual synthetic fibre and rubberized coating.

And, just in passing, an acquaintance into America's Cup type sailing suggested that kayaks would be more efficient to paddle if they had a bow bulb like the fasted sailboats are now using (along with big ships, whose owners claim a 15% energy saving using them). I know they would interfere with riding up onto sheet ice, but... That's about what drafting bike riders save, which makes quite a difference...