10.10.2011

Twister


 One of the tricks to smoothing out imperfections in the hull shape is to apply filler with a notched blade. This creates triangular ridges that make sanding large surface areas fairly easy because you're just knocking off the tops of the ridges rather than having to sand a solid surface.  In this instance, I'm using a mixture of a little more than two parts micro balloons to one part epoxy; mixing the heck out of it with a drill and paint stirrer. I decided to tint this layer so that I could distinguish between each application of fairing material.

 

Application of the filler seemed to work out best with a trowel that I made from an 8 inch sheet rock blade.  I found that 1/8 in. notches every half inch worked well.  I just cut them in with a file. 


 

 Once this fairing compound was applied and cured, I used a 4ft. sanding board to fair the hull by hand. With the ridges running fore and aft, I worked the sanding board at 45 degree angles from left to right and right to left.  I made the sanding board from a lightweight cedar board and a carbon fiber tube. I also discovered that I could introduce a precise curvature in the sanding board by securing a small strap across the tube with sheet rock screws. By adjusting the tension of the strap I was able to create a slightly curved board that followed the overall shape of the hull.

With an ipod and a little shoulder work, I was able to smooth the hull down until the high points just began to show.  At first, it seemed to be a daunting task to hand sand two 44ft hulls, but breaking the job into a few sessions over a couple of days made all the difference. After a few days of this, If asked, I would have to decline an offer to play a game of Twister.

After sanding the tops off the ridges, I used a straight blade to fill in the grooves with untinted epoxy micro mix. 

 This resulted in a good start to a fair hull.  From here, I'll use finer and finer grit paper to eventually arrive at a surface that is suitable for a final top coat.