Last year, I built a CLC Patuxent from a kit, so I had the "good" wood - and it was a pleasure to work with. I just finished a cedar strip kayak, and needed some plywood for hatch and cockpit spacers. Since almost none of the wood shows (just the hatch lip when the hatch covers are removed, and the edges of the spacers for the cockpit coaming - I used cedar for the coaming ring), I took the "cheap" option and went with 1/8" and 1/4" luan. The only good thing I can say about the luan is that it was cheap. It was very difficult to work with - it splintered easily and was difficult to cut and plane because it had strands of string running through it (for strength?) The 1/4" was easier to work with than the 1/8", but is rather heavy for a S&G kayak, and I don't think it will bend well enough for some designs.

If it's all you can afford, go ahead and use it. But beware that there are some possible problems.

First, I don't think it really matters if the glue is interior and exterior. After all, most strip builders use regular wood glue, not the waterproof varieties. But you need to make sure the boat is waterproofed with glass and epoxy.

Another concern is voids in the wood. These can cause two problems. First, it is weaker and more prone to failure. Also, the bending properties are different at these points, so you may not get a smooth curve along the length of the boat. Check the edges of the wood after you cut out the pieces and fill any voids you see.

Above all, luan is ugly - at least compared to okume. The local lumber yard where I got the luan did have other species in 1/8" thicknesses. Some of these may be better looking. The price differed by species, but I don't recall the difference being staggering. You may want to spend a couple of extra bucks for the deck.

To make sure you have the boat waterproof - and have enough strength in those panels - you need to glass the boat inside and out. Personally, I would do that even with 4 mm okume. You can go with a cheaper, ligher weight cloth on the inside. I used a 2.4 oz glass inside the hull and on the outside of the deck on my Patuxent, and it is holding up quite well. I just epoxy saturated the inside of the deck, and wish I had glassed that as well - probably would have prevented that crack. So even 3mm (1/8") okume has problems.

Use the internet to shop around for materials. You may find significant savings on glass and epoxy - the most expensive components of a S&G kayak. Prices on MAS epoxy vary by as much as 30%, and glass prices are similar.

Good luck,

Ken