Wednesday, February 24, 2010

I’ve built the centreboard and rudder casings and given the insides 3 coats of epoxy before final assembly. I’ve made the casings 3mm wider than the foils, so I spent a good amount of time getting all the internal framing spacers planed to exactly the right width. This is where a table saw or thickness planer would have come in handy. I want to add some strips of lexan or similar to snug the boards up and which will also take the wear away from the epoxy coating inside the casings.
100_6886.jpgThis shot shows the structure of the centre board case. The spacers are Paulownia.

I also tried something that I first tried with success when I made the foils. Immediately after laying down the final epoxy coat, I covered it with non stick oven paper and used a squeegee to remove all the air bubbles and even out the coating. Because it is silicon impregnated, the oven paper just peels off when the epoxy cures, leaving a nice smooth surface that doesn’t need sanding or further treatment. I knew it worked on curved surface but it’s good to know that is also works just as well on flat ones. The important thing I think is to make sure you lay the oven paper down straight away while the epoxy is still able to flow and spread, otherwise you may end up with a smooth but lumpy surface.
100_6920.jpg Removing air bubbles with the squeegee.
100_6921.jpg Air bubbles removed, now just waiting for the epoxy to cure before the oven paper is removed.
100_6925.jpg With the paper removed, the finish is smooth But matt. Another good outcome from this method is that flying insects and dust can't affect the surface.
100_6924.jpg Make sure you are using a non-stick type of oven paper. This paper is silconised and is not the "greaseproof" sort.

I had to stuff around with the tiller as the arms would not bend around the rudder case without pulling the back end of the case open due to the angle. This was a downfall of making the tiller before the case, which I had done while waiting for my ply to arrive from France (via Tasmania). There was just too much stress on the back end of the rudder casing so I’ve cut out one of the Paulownia spacers on the tiller and now it fits just fine. Before I can assemble the rudder case, I have to buy some SS bolts to fix in during assembly as the bolt heads need to be inside the case.

I received a phone call from the chandlers to say some Ronstan rudder fittings I had ordered months ago had arrived. I had cancelled the order, but through some stuff up they did not cancel the order with Ronstan. As I’d paid a $40 deposit I decided to go over anyway and pick them up, and then make a decision about which ones to use, the Ronstan or the Riley I had also bought from another supplier. The Ronstan ones are alloy and fitted the width of the rudder casing just perfectly and without any modification which I would have to do with the other Riley SS ones. The 8mm Riley SS pin also fits the 7.9mm Ronstan holes just perfectly too, without ANY play at all, so I’ve decided to go with the lighter Ronstan ones.

See you next time!

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