Finally, the last fibreglass Panel is laid in the interior. I have not used peel ply for the last three panels. The reasons are that any 'outgassing' forces the peel ply into a big bubble (say 2 - 3 cms), and messes up the finish making lots more work. It is much easier to cope with smaller outgassing bubbles when the peel ply is not there. I have still gotten a quality finish by doing 'wet-on-wet' layout. This involves wetting out the fabric with just the minimal amount of resin (merely makes the cloth transparent), then when the epoxy goes tacky - applying another coat over the top, thinly, to avoid runs. This results in a very even layer of fibreglass, with just a small ripple of the cloth weave to be seen. Once this epoxy has hardened, any runs and rough bits can be sanded back without cutting through the cloth. Then a final thin coat can be laid over the top when the canoe has been turned to the horizontal, thus avoiding runs in the final coat. If I wasn't able to lay the canoe more or less horizontal for the final coat, I would use the peel ply.
EndLess Sanding Nov 4
Part of the pain using clear epoxy is having to sand back the latest layers ready to put another coat on. For people with a weak arm, this would be the worst torture - it annoyed the &^*#$&! out of me!!! It seems there is more epoxy sanded off, than painted on. Usually, a second coat is laid over the first coat of epoxy while the first coat is 'tacky'. This produces a good finish, but then more sanding is required to remove runs, fibreglass weave patterns etc before the third final coat is added to create a good waterproof barrier. Then the third coat has to be sanded smooth prior to the varnish coat. The use of good quality air masks, gloves and constant cleanup with an old vacuum cleaner makes the job bearable and less itchy.
The Extra Rib 11 November 2007
Traditionally, Canadian canoes have a supporting bar across the centre to provide rigidity to the sides. I am keen to minimalise the need for a permanent bar to make accomodation more flexible. So, to make the sides more rigid, I am building in some internal support. This will take the form of an internal rib. Thin wooden strips can be steamed to fit, but I have found that if a layer of fibreglass cloth and epoxy is applied to one side of a thin timber strip (say 3/16" thick), then the strip can be bent around very sharp bends, with the fibreglass on the outside of the curve. This photo shows the fitting of the main rib, which will be glued into place and have a layer of fibreglass applied on the top to provide extra rigidity.REVISED PLAN - I fitted the rib by applying pressure to the ends of the strip, and weights on the strip of wood. In future, I would run temporary bolts right through the hull, backed up by temporary blocks of wood. This would ensure a closer fit the the shape of the hull, and save a lot of back filling with resin. Note on the concept October 2013 : This was a great idea. After several years, the hull has remained rigid, and survived undamaged being blown by strong winds - 30 meters off its stand down a hill, with no damage. Structurally and aesthetically, it has been a great move.
Building Edges 22/Nov/2007
The gunwale edges are being built up by adding three parallel strips, laminated together, and one horizontal top along the edge. It takes a lot of clamps to ensure reliable gluing, and not leave any gaps. Seat supports have been added over the centre rib, and foam flotation has been added to the forward bow. The seat supports were initially invented to provide more rigidity to the interior frame. As it turned out, they were very handy for mounting the optional centre seat to as well. I drilled holes through each one, and this proved very useful for supporting the hull in different positions while working on the interior by suspending the canoe from a rope inserted into the holes.