For the very latest activity, click here: From a Bare Hull

Sunday, October 08, 2006

Infusion Table Test

Did a test with the infusion table this weekend. Took a small piece of Coosa, wrapped it with a layer of glass and infused in on the table (per the steps in the previous post). Generally, all went pretty well and the test came out good. The only problem was that I put the side that had the "doubled up" glass due to overlap, side DOWN. That created small gaps between the table and the flat edge. This created areas that did not laminate to the piece. Solution, put overlaps side UP.

Sunday, October 01, 2006

Infusion Table

This past week saw the preparation of a tool which I hope will save some time. I plan on using infusion to skin larger pieces of Coosa to keep the weight and mess down. It would be nice to skin them before they are permanently installed. The infusion table will hopefully save setup time. The idea is the large flat parts will be placed on the table. Sealed and bagged. Vaccum applied to the top, with resin being fed through holes underneath. Construction is simply a sheet of 1 inch plywood with the smooth side coated with a high-gloss two-part polyeurathane finish to help discourage parts from sticking to the table. The general procedure with such a table will be something: 1. Place part on table. 2. Outline part with sealing tape. 3. Remove part. 4. If necessary, drill resin feed holes strategically. 5. Spray part area with mold release wax 6. Wrap part in glass, peel-ply and flow-medium. 7. Place on table and seal with bagging film. 8. Apply vaccum and feed resin from tubes underneath. Voila! Repeat for next part. In order to help even flow distribution, multiple resin feed ports can be drilled, and if necessary, flow channels can be routed in the topside. Obviously this will be a disposable tool. As more parts are made, the more holes may be drilled and the less useful it becomes, but it should be good enough for one boat. This weekend saw the last coat of finish applied. It will take a few days to fully cure, so next week will be the first infusion test. Stay tuned.

Main Mast Step Installation

This weekend saw the Westsail's main mast step installed. The masts on W42s are deck stepped, but there is a compression post that sits between the underside of the deck and the keel to distribute compression loads from the mast. This post is typically a length of 2 inch stainless steel tubing. The original W42 plans called for a steel I-Beam about 3 feet in length to be installed underneath the floors. As the W42s were rigged in different configurations, this made it easy to spot the mast forward or aft, depending on the configuration. This hull did come with the beam installed, albeit supported by rotting floor timbers which were torn out (see archives). Since this boat will be a ketch, there is no need for such an I-beam. So, the compression post will be stepped all the way to the keel, but there will need to be some sort of pad to help spread the load. The pad was made from Coosa board. Seven pieces of 3/4" inch coosa were laminated together into a "block" large enough to fit between the two floor timbers where the mast will be stepped. The block is orientated such that the roving in the coosa will be vertical in compression. The underside of the block was cut and shaped to fit the form of the bilge as close as possible, while keeping the topside level and square. For the permanent installation, about 3 quarts of resin was heavily thinkened with milled glass fiber and poured into the bilge. The step was then tapped firmly into the resin and made level and square. The picture shows this installation. The plumb-bob is approximately where the compression post will be. The step still needs to be skinned with glass and accomodations made for limber holes. That is in an upcoming project.