Fiberglassing the Interior of the Canoe

The past couple of days I finished fiberglassing the inside of the hull of the canoe. It was really difficult but I also learned a lot. I don’t have any photos yet but I’ll post them in a day or two.

Because my fiberglass cloth is only 40″ wide, I can’t use a single piece to cover the inside. That’s ok because I wanted to lay the cloth across the width of the hull. Several pieces are laid across, overlapping by 4″ or 5″. Some people propose that these overlaps acts as stiffeners. I’m not sure about that, but it couldn’t hurt. I thought using several smaller pieces would make the work less cumbersome than 1 big piece. More on that later.

It took 5 pieces to cover the length of the hull. At the stems I cut down the middle so I don’t have to worry about wrapping the cloth over or around the stem. I used plastic clothesline clips to hold the cloth to the hull and I used a brush to flatten and even out the cloth. The plan was to use a roller and squeegee to spread the epoxy.

As soon as I started I encountered some problems. My epoxy had been sitting for a while and consequently had partially chrystallized. I heated up the epoxy and that got things flowing again. After the first batch of epoxy was put on the boat though, the resin pump jammed. I had to work fast to get it going again because I couldn’t let the epoxy on the hull kick, or I would have even more problems. I stayed calm though (I tend to get excited with things like this) and this became a common theme for the next 2hrs. Stay calm, it’ll all work out…

I had a few problems with keeping the cloth down on the hull but this was anticipated since the stems make things difficult. My first method for spreading epoxy was pouring it on the bottom and spreading with the squeegee. This worked well until I hit the curve of the bulge. I then started using a roller which was okay. However, a significant problem started happening. I could not for the life of me get the cloth to lie flat on the hull. Large pockets of cloth were lifting up. I was trying to move the wrinkles with a squeegee, roller and my hand. I also started to use a brush near the end. After a long, long struggle on the second piece I had to lift the wet cloth off of the wood and try to set it back down again. Things were getting really tense because the epoxy was going to be kicking soon. I managed to get the cloth in place but still had a few big pockets. I finally resorted to using my utility knife and cut slits in the pockets to get them lie flat.

After 2.5hrs of struggle I was finished for the night. Luckily I could stop early because I was using separate pieces of cloth. I got two pieces down, and hoped to finish the other 3 the next night.

For the next night I decided to take a slightly different tact. I decided to use brushes, and I made sure to spend a lot of prep time getting the cloth down flat on the hull as close to perfect as possible before starting with the epoxy. I thought I had been careful with laying down the cloth the first time, but now I was going to try and do an even better job. I bought some disposable natural bristle brushes from Lee Valley (cheap and good). Trying to clean epoxy brushes while mixing epoxy, spreading epoxy and squeegeeing epoxy is all but impossible. I’m not even sure that the chemicals used to properly clean a brush is worth it – vinegar works great for cleaning epoxy from skin and other things but I find that acetone is needed for a good brush cleaning. What’s worse, using acetone and re-using the brush, or using nothing and throwing the brush away?

I spent 45min getting the rest of the cloth in place as best I could. I then mixed my first batch of epoxy, poured it in the boat and slowly and carefully spread it with the brush. The brush allowed for a lot more control: the cloth will move around and the brush is very accurate in controlling the movement. Using a roller gives another problem in that it can lift the cloth up off the wood as the cloth sticks to the roller as it turns. The brush doesn’t have this problem.

Much to my pleasure, I didn’t really have any problems with the last three pieces of cloth. My work wasn’t perfect but it was faster and better than the previous night. As well, I didn’t need to slit any bubbles!

There are a few things left for me to do on the inside. I am going to sand down any bits of cloth rising up. As well, some resin chunks were in the epoxy from the first night so these will be sanded too. Then I will patch the areas with slits and give a thin coat of epoxy over the rest of the hull. I think it won’t take more than an hour.

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