More sanding, more fairing putty ... sigh

 Well, I think I can see the light at the end of the starboard float tunnel ... or is that a train!?  I sanded down all of the fairing putty I applied the past couple weeks.  This was a lot of effort, requiring about 5-6 hours of continuous sanding, but the result was very nice.  The reinforcing layers of glass blend in with the hull seamlessly.  And most of the putty has ben removed so the glass pattern is visible, though perfectly smooth.  I was careful to only sand to the top of the glass so I wouldn't remove the structural glass fibers.  The glass tends to be much more "slippery" under the fairing board, whereas the fairing putty produces significant friction and needs much more effort to push the board over.  By noticing the difference in the feel, not to mention the appearance of the glass fabric pattern, I was able to gauge when an area was sanded enough.

 Here is a close up view of the bow after sanding.  The layers of glass are pretty clear, but if I close my eyes and run my hand over it (with a nitrile glove on so I don't get any skin oil on the epoxy) I can't tell where the layers transition.  I did use the power belt sander a little on the second day of sanding to knock down the high spots in the skim coat.  This made the hand sanding with the fairing board much more bearable.  But be very careful with the power sander because it only takes a moment for it to cut through the fairing putty and into the glass, leaving a low area.  Keep the sander moving at all times, and go over a large area uniformly for an even effect since the sander isn't big enough to blend areas greater than about 6 inches.  I also stopped early enough to leave material for the fairing board to do it's job blending larger scale, irregular surface features.

After the sanding work, I carefully inspected the surface to find the few remaining low areas and discontinuities at the edges of the reinforcing layers.  I then applied very thin layers of fairing putty with a wide squeegee.  I tried to minimize the amount of putty applied so I won't have to do much more sanding.  If you look closely at this photo you can see the shiny areas where the putty was applied.  I'll do the same on both sides and then make the final pass with the long board.  After that, we are on to hatch and port installation.

Send in the reinforcements

 We finished shaping and blending the bow foam into the hull.  We made two passes with filler, sanding in between, and the result was a seamless join.  Then I spent some time fine tuning the shape so both sides were as symmetric as I could get them.  The bow reinforcement consists of two layers of 12 oz glass, with staggered overlaps so it blends in more easily.  I also added an extra layer along the forward keel where some of the original glass layers tended to get sanded through.  I applied the first layer and then let it set while I worked on other sections (see below). Letting the epoxy kick a little  allows me to apply layer on top of layer without disturbing the first layer. You might notice I also applied some peel-ply to the top and bottom of the bow to hold the glass ends in place while the epoxy set up.  Tomorrow I'll sand off the gloss surface and skim coat the bow to finish blending.

While waiting for the first layer of glass to kick on the bow, I applied reinforcement glass around the areas where the beams will attach to the float.  I had to sand off some fairing putty where I was overzealous in my skim coat.  Then I carefully marked the boundary of the reinforcement based on the detailed placement instructions that Ian Farrier includes in his plans.  I had to think awhile about the meaning of "inner edge of the beam cut out."  On the one hand, it could have meant the edge closest to the boat centerline.  On the other hand, it could mean the edge closest to the centerline of the float.  If you think about it, these two options are opposite edges of the beam cut out.  I am sure it was obvious to Ian when he was preparing the plans, but I had to study his plans carefully to conclude he meant the edge closest to the float centerline.  In general, his plans are very clear, and I am sure this was just a case of me being overly analytical.

As with the bow, I will sand these reinforcement layers lightly tomorrow and then apply my thin formulation of fairing putty.  I will also skim coat the rest of the deck, which is the only area with the bare glass and epoxy still exposed.  You probably already noticed that I turned the float to its proper upright orientation with some help from Dad.  So gravity will help me spread out the thin skim coat on the deck.  Once the skim coat cures, I'll start final fairing next week ... yeah, can't wait ...

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.

Shaping the bow

 We made lots of progress on shaping the bow and blending it into the forward hull section.  In this first photo the bow has been shaved and sanded to match the hull.  This is the second layer of filler putty applied to fill the remaining gap between the hull and bow, as well as any slight blemishes.  The green squiggle in the middle of the bow marks the middle layer of foam in the original foam block.  I tried to keep track of this layer to help carve the bow symmetrically.

In this view we flipped the hull over, so the outside half of the bow is now on the bottom.  I finished sanding down the putty applied previously so the bow is perfectly blended on this side.  I am waiting for a skim coat of fairing putty to fully cure on this side as well, so we rolled the hull over so I could work on the inside half.

Here is the inside half of the bow after initial shaping and sanding to match the hull.  I used a hand saw to slice off layers of foam using the hull as a guide, then I shaved the foam smooth with a "cheese grater" style plane.  Final shaping is done with the rigid long board keeping the board moving parallel to the length of the hull off the bow end.  The result is a quick and fair match of the bow to the hull.  I applied putty (150 mL epoxy + 1 cup balloons + 1/4 cup cabosil to reduce running) to fill in the seam and imperfections, then skim coated the forward hull with the extra.  It looks good already!  Unfortunately, winter made a late spring appearance, so the epoxy is slow to set with temperatures stuck into the 40s.