My Petrel has been my primary boat for a long time. It has been through some serious abuse over the years. Not only has it been dragged up beaches and bumped into the occasional submerged log, I've also crushed in the side playing in rock gardens, I've stored it outside all summer in the sun with no cover, and kept it outside, uncovered all winter, I've also left it on the roof of my car while running errands around town. After all this abuse it was looking a little shabby. It was still perfectly functional and attracted more positive comments than your typical plastic boat, but I only have a limited number of boats to bring to shows and it was no longer the best representation of my work. The original Cordovan mahogany stain color had faded significantly due to the time out in the sun. The areas where I had made repairs after hard hits had newer stain which was not as faded and showed up as dark patches. There were some deep gouges that would require deep sanding to eliminate.
I could always give it a light sanding and a fresh coat of varnish and it would look better, but I decided it was time for a significant refinishing. I thought the best option was stripping off the glass and starting over from freshly sanded wood. There was a lot of procrastinating. The idea of removing the glass was not very appealing. The most obvious method was to sand it all off. This seemed like a horrid undertaking with pounds of dust produced and lots of itchy skin.
After a lot of deliberation I decided to hit it with a heat gun. This worked very well. It took a lot of heat and still wasn't always fun, but it allowed the fiberglass to come of in large sheets, instead of clouds of dust. The whole process of usable kayak to refreshed usable kayak was about 4 days. I cut some corners to fit the project in between other jobs, but the results are worth it.
It takes a lot of heat to soften the epoxy. A good, powerful heat gun is required. This is not a job for a hair drier. I started by heating a relatively small area, keeping the gun moving to avoid scorching the surface too much. It takes a while to get the surface hot enough, but after a bit tiny spots would appear under the glass. These quickly expanded into a large blister. By heating around the blistered area I could make it expand a bit.
The blister was a result of trapped air/steam expanding and lifting the glass. As soon as a leak in the blister appeared it would stop expanding. Continued heating around the area allowed me to get a putty knife in under the surface and coax more glass to separate from the wood.
The glass would generally pull away from the wood while leaving a thin layer of epoxy bonded to the wood. Occasionally it would pull up a little wood with it. This usually happened when there was not enough heat in the area. With enough heat, the peeling process was actually kind of fun and went easily. Some of the patched areas where I had previously sanded into the surface and added new glass did make for tricky spots, and the bottom that had two layers of glass required I pay attention to how many layers I was peeling at a time. It was best to peel both layers at once.
After all the glass was removed, I cleaned the remaining epoxy off the wood with 36 grit sandpaper on a random orbital sander. This stuff is basically the consistency of asphalt pavement and is pretty effective at removing the residual epoxy, but left a texture similar to road rash. I then sanded the whole thing with 60 grit sandpaper. I didn't go any finer. The only scratches that showed up were where I didn't sufficiently sand away the road rash. I didn't want to sand too much as the strips were getting a little thin.
The freshly sanded wood accepted stain well and then I went directly to fiberglassing. I didn't get footage of the glassing because I was in a bit of a rush. I masked off the deck and put two layers of fiberglass on the hull. Two layers of glass at once does trap some air between the layers and I got a fair amount of cloudy areas due to my impatience. I then flipped the boat over and overlapped the deck glass on to the hull.
The hatches got distorted as I peeled off the glass. I made some temporary forms to hold the hatches in shape as I sanded and glassed.
After two quick fill coats and a quick sanding I brought the boat outside for 3 quick coats of varnish. On a hot sunny day I slapped on the varnish as fast as I could, waited and hour and slapped on another. The finish is filled with brush marks and not exactly "show room" quality, but by the next weekend it was already accumulating scratches.