: This may sound like heresy but I was wondering why an aluminum kayak would
: not be feasible.

: I have made a CLC stitch and glue and my idea is to cut aluminum sheet panels
: as is done in a stitch and glue and weld them together.

Consider a skin on frame style rather than a stitch and glue style. If you look at the work that Mike Hanks did with converting a skin on frame kayak to a plywood skinned version ( he used George Putz's "Walrus" design) I think you can see some potential ideas.

First, with a wood boat the fiberglass provides a lot of strength. You will not have that with an aluminum boat, so you will want a design where the structural strength is not dependant on the shape, stiffness, or material properties of the hull's exterior. The trestlework bracking used in the Walrus can be duplicated with aluminum rod or bar stock. The resulting frame should be as strong or stronger than one made from wood. At that point the skin can be made from very thin aluminum material, or you can go with sheet materials that are as thick as you like.

There is another nice thing about the Walrus design and Putz's way of construction. You can use his form designs and install wood stringers, then lay your sheets of aluminum over these (you'll have lots of spaces to clamp them to hold them in place) and cut the aluminum to size by merely tracing the lines of the chines onto your metal sheet. Cut it, clamp it back in place, and run a weld along the seam. Then go on to the next adjoining panel.

You can use aluminum bar stock for the chines, and weld the panels directly to that. The heavier material will reinforce the joints and provide greater stiffness. It may be possible to use a thinner sheet material, thus reducing the weight, by adding this continuous reinforcement along the seams.

As for bulkheads> You should have several. If I was going to try building a boat from aluminum I'd build the bulkheads from plywood which I would cut to the shape of the cross section, or frame shape, of the boat. I would then bend a strip of 1/8th inch aluminum around the circumference of the plywood bulkhead, and clanp it tightly to the wood. While it was held this way, I'd weld on tabs, and use sheetmetal screws to hold the tabs to the plywood. Then I could release my clamps and have that wood panel surrounded by the aluminum. The bulkhead would be placed into position, the screws removed, and the wood taken out while the remaining aluminum rim is welded into place. I'd seal all crevices with an epoxy-based body filler. Then I'd coat the wood with epoxy resin(at least 2 coats) to waterproof it, and I'd reinstall it with the screws, and some silicone sealant around all edges. I might put a commercial plastic acces port in the center of the bulkhead for easy access to the compartment.

the concerns about getting cut, and sharp edges don't make much sense to me. I assume you would finish all edges with some reinforcement. The cockpit in particular would probably be made of flat bar stock, or perhaps angle stock.

: Does this make any sense or am I missing something?

It makes a lot of sense, but not everyone has access to the materials, nor the skills and tools to weld aluminum.

: What problems do you anticipate? I live in Southern California so the lack of
: insulation from the water should not be a big problem.

If I recall correctly, in a history of the business which I read many decades ago, Grumman started building canoes right after WWII because they had a surplus supply of aluminum, and no more contracts to build airplanes for the military. Their first canoes were tested in fresh water and on the basis of this they built more. Unfortunately, the alloy they used corroded rather rapidly in salt water, and they had boats which practically dissolved. The moral is: They found an alloy that is very resistant to sea water, and you should do the same.

: Happy Holidays!

The same to you, and have fun building your boat.

PGJ