Sunday, May 1, 2011

Skim coating and final fairing

 In addition to shaping the bow, we also started skim coating the hull to fill the fabric weave and blended the edges.  The process started with sanding the entire surface to remove the glossy epoxy surface.  The best advice I have for this step is to cover up as much as possible to keep the dust off your skin.  Although I try to minimize the amount of glass fiber that is removed, some glass is sanded off, and it is the best itching powder ever!  I wear a tyvek suit, nitrile gloves, work gloves, and respirator with dust cartridges.  I wish I had long gloves to keep the dust from sneaking up my sleeves, but this keeps the discomfort to a minimum.  The objective of the sanding is not to make the surface smooth, but just to knock off the gloss so the skim coat will properly adhere.
I use a thin putty mixture (150 mL epoxy + 1 cup balloons) for the skim coat.  This allows the putty to flow smooth and naturally fill the weave and low areas.  I spread it with a wide squeegee and work it into the surface texture, then gravity takes over.  The result is a glassy surface that gives an idea of what the final painted result will be.  I try to keep it as thin as possible while still filling the weave.  Once this skim coat cures (which will be longer thanks to the unexpected May snow showers!) I'll sand it fair with the long boards.  I expect I will need one additional pass with the fairing putty to fully blend in the edges of the reinforcing fabric layer.  Based on my experience so far, I expect only about 20% of the applied putty will stay on the boat, with the remaining 80% ending up in the vacuum cleaner.

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