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The Recore Part I

With the loss of time I had now obtained, I realized that I was into a crunch period. I had plans to go to Schroon Lake in upstate New York the last week of July and the first week of August and I knew with the Ventura barely into it’s restoration that I would be working on it endlessly right up to the last minute. The recore would have to take place outside in the cold with the dust from the cutting wheel and the fumes from the resin, a well ventilated area would be in order. The boat was put up on blocks with supports being placed under the area where the work would be taking place. It is best to get the boat off the trailer so the hull can hold the same as it did when the core was in. There should be no pressure pushing up on the bottom of the boat, so when installation of the new core begins the balsa lays in flat for a greater seal, with the least amount of air pockets as possible. With breathing apparatus applied, face shield on and proper clothing attire I began cutting lines one inch apart horizontally and vertically into the balsa using a Makita portable grinder with a 4" x 3/32" x 5/8" reinforced metal cutting wheel. I cut the lines at approximately 1/8" in depth as I was made aware that going any deeper than that could damage the hull. When that process was complete I peeled off the fiberglass exposing the rotted balsa, and at this time the hard part began. The balsa, even though it was saturated, was next to impossible to remove from the floor. I used a 2" wide putty knife and began chipping at it carefully. Caution has to be taken while doing this process; if the knife is not held flat while chipping then there is a good chance of sending one of the edges of the knife through the bottom of the boat. I recommend using a putty knife that has about a 45 degree angle designed into it. While chipping, some of the 1" x 1" squares came up very easily while most others took several minutes to remove, and because it can take so much time on one square alone this process becomes the most time consuming of the entire recore. After a few weeks I was finally finished removing all the old balsa. Some of the balsa was impossible to remove using the putty knife being it was so well fused into the floor. The surface was still rough and had to be smooth and flat for the installation of the new core. For the next process I used a Black and Decker belt sander with 36 grit sanding belts and on a slow speed began sanding any leftover balsa that was still fused to the floor. Again, caution has to be taken at this time because if the sander is held in one spot for too long of a time then thin spots can be worn into the floor to the point where daylight can be see or even worse a hole in the bottom of the boat can be made. This process is a very effective way to smooth out the floor in preparation of the new balsa. When I was completely finished I vacuumed up all the dust that was made during sanding and used a rag and mineral spirits to make sure the area was completely clean as any left over dust could impair the resins ability to bond.