I went to ask at our local plastics dealer and his suggestion was ABS plastic and the material used in white plastic cutting boards which I believe is a crosslinked polyethylene. They both machine well and are durable. UV is a concern, as I don't have any information on it's long term exposure results. I was able to bend it very easily using the kitchen stove element and the countertop to shape it. The resulting blade is stiff and durable, but has enough flex for the occasional bump on the bottom. I used the white polyethylene to carve up large "washers". The material is inherently self lubricating. The design is from observation of other kayaks and was very simple to fabricate.