Tuesday, May 29, 2018

End of the Sportfisherman Fairing

Kevin has been finding muscles in places that didn't have muscles before. Longboard sanding large surfaces tends to have that effect. But it is a process that must be gone through if the boat is to have a really nice standard of finish. Any shortcuts at this stage of the build will show in the final finish and take even more work to improve later.

I described the general process of filling/sanding/fairing/sanding in my previous sportfisherman blog post. Now, to round off the process, Kevin sprayed on three coats of high build epoxy for the last sanding operation. This layer is much harder than the sprayed fairing layers, so much tougher to sand. Before sanding he sprayed on a guide coat composed of denatured alcohol with food colouring mixed into it. This is sprayed on in a thin film that leaves a very thin coating of colour after the alcohol has evaporated off. Longboarding this surface removes the colour on the high spots and leaves it in the low spots of any texture on the surface. Continuing to sand until the last of the colour has gone ensures that there is no orange peel or other texture left to detract from the gloss finish coats that will follow later.
The blue in this photo is the guide coat of food colouring and denatured alcohol that was sprayed on to assist sanding.
With sanding nearly finished, the hull is showing a good standard of fairness and finish to form a smooth foundation for the high gloss finish coats.
While Kevin was developing his muscles I was stripping out the temporary frames and formwork from inside the hull, items that are no longer needed to support the hull. This is to reduce weight for when the hull is turned over.

The next step was to start building the frames around the hull that will protect it and provide support while the boat is turned 180 degrees. These frames are at permanent frames 3.5 and 7, which spread the hull weight evenly and also are of similar width, allowing two similar frames to be built. The first parts added were the bottom frames, bolted to the frame bases, stiffening them considerably. With those in place the hull was raised with a trolley jack and blocked a few inches clear of the building stocks. Then the stocks were taken apart and much of the timber reused to build the turning frames. Once the stocks were out of the way we jacked the hull again, removed the blocks and lowered the hull to stand on the frames, resting on the floor.
Turning frames built around the hull, with carpet padding between the frames and hull. The diagonal braces needed to stabilise the frames must still be added.
With the temporary frames removed, the structure of the hull is more easily seen.
Work on sanding the hull, applying barrier coat to the bottom and completion of the turning frames is continuing, in preparation for turning the hull this weekend.

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