We developed a method to space multi-layered reinforcement uniformly in the composite section without using permanent spacers. We decided to use three layers of an unimpregnated graphite fiber mesh to reinforce our boat and tested our construction technique by placing several test plates.
The plates performed so well that we decided to place our boat in a similar manner. Here's how we did it:
We began by coating a male mold with a sheet of plastic. The first layer of graphite mesh was draped over the mold, and 2.8 mm (0.11 in.) diameter wires were positioned transversely at 7.6 cm (3 in.) intervals down the length.
Our team placed the canoe over this configuration and used drywall knives to level the concrete to the upper surface of the wires. After the concrete had dried for 12 hours, we removed the wires.
We repeated this process for the second layer of mesh, making sure that new wires were not placed over the freshly filled grooves left by the first set of wires. After an additional 12 hours, we removed the second set of wires and applied the third layer of mesh before placing a final layer of concrete.
The advantage of using this method is that the stress concentrations, ordinarily caused by the inclusion of small spacers in the canoe, are eliminated. It provides a uniform thickness and significantly enhances quality control giving a very good outer surface.
Why not try it for yourself?