Monday, October 17, 2011

Arts and crafts, part I

In the first of a two part post, Jeff and Anne aboard s/v C'est la Vie show us how to use modeling clay and epoxy to make professional-looking raised platforms for their chainplate deck penetrations. This is a two-part post because Jeff does such a good job of describing the work and the problem-solving process - a great read and an inspiration to all of us.
With all the standing rigging down the time is right to tick off a long time resident of the projects list - rebuild the chain plate deck fittings.   I'm unsure of the technical name for these things, but they serve to keep water from intruding into the cabin where the chain plates pass through the deck.  They perform this task in two ways.  First, they are raised so thin sheets of water running across the deck will pass round the structure.  Secondly they have a recessed reservoir that when filled with caulk and compressed by a metal top plate forms a water tight seal around the metal chain plate. C'est la Vie has four such fittings on her deck.  The aft fittings are doubles and accommodate the cap and aft lower shrouds.

Visible in the image above is a green outline of what I envision the for the shape of the finished product. The forward fitting is a single chain plate that serves the lower, forward shroud.

In the images above the metal fittings are the chain plates.  The yellow modeling clay is filling the reservoir and extends above the height that I plan to build up the new fittings.  Surrounding the modeling clay are the eroding remnants of the original fittings.

At the the stage of the process pictured above, I have drilled out and refilled with epoxy the four screw holes used to tighten down the metal top plate.  With these holes filled the next step was to create a mold for the new deck fitting.  Modeling clay works well as a mold for epoxy, but how to create nice round ends and straight sides?  I searched around the boat for a something that looked to be the appropriate radius.

Can't use the can, but the lid will do nicely.

I cut the plastic lid in half vertically for use as a guide, and then molded the clay around the lid.

Once the round ends were complete, I used a straight edge and a box cutter blade to clean up the sides of the mold.

Repeat this process on each of the four fittings and it is time to pour the epoxy.  I used West System epoxy thickened to a consistency somewhere between honey and ketchup with high density filler.

Allow epoxy to fully set... see part 2

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