May 17 & 18, 2019
I began Friday afternoon by preparing for the fabrication of the sail drive mount. Well, more like a recessed space that the Torqeedo's sail drive mounting pad could be recessed into, helping to achieve proper alignment. Previously, I had used the router to remove a significant portion of the laminate aft of the rudder and in the surface of the counter. I had routed deeper into this area in the forward portion, and gradually made shallower cuts as I moved aft. The purpose for this change in depth of cut was to produce an angle that would put the sail drive in a slight descending orientation.
With the rough opening prepared, I took measurements for a mounting "tray" that would be fiberglassed into the rough opening. The planned "tray" would include a recess that the Torqeedo's sail drive mounting pad would fit within. The overhead work required that I do this in two parts: first created a rough opening, then create the recess for the mounting pad that ultimately could be glassed into/onto the rough opening.
Anyway, I took measurements of the rough opening to understand the maximum dimensions that I had to work within for the mounting pad "tray".
Using a piece of pressed board, I cut four sections that would create a mold to lay up fiberglass for the mounting pad's tray.
I taped all surfaces of each of the four pieces, including the mounting pad itself (the black teardrop piece on the photos), to prevent the epoxy resin from sticking to them.
I then cut the required pieces of 1708 biaxial fiberglass cloth for the tray itself.
I prepared the fiberglass cloth by applying epoxy resin to wet it out, and then assembled the mounting pad and mold.
I first laid the fiberglass cloth in the mold, alternating a layer across the bottom, then a wide layer that ran up both lengthier sides, then two narrow strips running up both ends, and a final wide layer.
I placed the mounting pad itself into the mold - fully taped to protect its surface. I then mixed batches of thickened epoxy resin to pour into the mold. The resin was thickened just enough to still allow it to flow, and it did nicely - filling in the voids around the mounting pad. I then placed the mold into the shop's refrigerator to help control the kick (heat) of the epoxy cure. While the epoxy kicked off, I moved onto other tasks over on the Allied itself.
Those "other tasks" will be duly noted, but first, let's get back to the mounting pad tray... I used the oscillating tool and cut along the center line of the now partially cured mounting tray, and then removed the Torqeedo's sail drive mounting block. I was left with two parts, cut along the center line, that perfectly replicated the shape of the mounting block. Since I wanted a fit that allowed for some bedding compound (Sitka Flex 291, or the like), my intention was to glass the two halves back together, but with a slight spacing imparted in the effort. To this end, I sanded the surfaces that would be re-bonding to one another, and then cut-off the excess glass above the mold itself. Using 10oz cloth, I bonded the two halves together, and then filled the new inner cavity with thickened epoxy. Once things cure, I will come back and add some additional 1708 biaxial to the tray to further strengthen the tray.
During the day, I worked on the thru-hull patches. First, I water-washed the previously applied, and now cured, thickened epoxy fairing compound, and I then sanded to knock down the worst of the offenders - those standing far too proud to the surrounding hull.
I worked from starboard forward to starboard aft, sanding with 80-grit discs and the 60" DA sander.
I continued around to the port forward...
...and then concluded on the port aft. I did come back with the 5" DA sander to work some finer detail into the effort in order to prepare for the final round of fairing compound.
Each of the patches were good enough for bottom paint and then go sailing, but I really needed to address a few low spots and voids....and, well, while I had things down to the bone, I wanted my work to reflect what the owner expects in his old girl!
I first wiped the surfaces clean with acetone to prepare for additional epoxy work, and then painted out the surfaces with epoxy resin (not thickened, or otherwise known as "neat" resin).
I then used a squeegee to apply thickened epoxy resin to the patches, filling in those last remaining low spots and voids.
I will come back, water-wash and sand, and as a final sealer coat, apply neat epoxy resin to guard against water intrusion. When the Allied 24 leaves my yard, the owner will be ready for a quick sanding of the bottom and a fresh application of bottom paint prior to splashing his old girl.
Before knocking off for the day, I moved up to the bow deck. There was a bit of unfairness to the surface of the bow that still needed to be addressed, so with the 6" DA sander in hand, I knocked down the high spots. I solvent-washed the surface and headed back to the shop to mix up a batch of thickened epoxy.
Using a lengthy trowel, I applied the thickened epoxy to the freshly prepared surface, working the fairing compound into the low spots. Satisfied with the fairing application, I'm now looking forward to sanding with a longboard to bring the surface to the point where I can apply primer.
Total Time Today: 7.25
No comments:
Post a Comment