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.

Tern 14 kayak update

Whew, it’s been a while since I’ve added any information.
I didn’t do much work on the boat during the summer. We were pretty busy and the longer daylight hours meant that I spent a lot more time in the evenings playing with the kids in the park and at the beach. I was pretty tired at the end of those days.

The progress I’ve made includes:
1. sanding the hull and deck to a flat finish prior to applying the polyurethane (almost finished)
2. glued the coaming spacer in place
3. laminated the coaming and cut it to fit on the spacer
4. 1/2 through making some wooden kayak cradles for the car roof rack

The gallery photos describe a bit more detail of the most recent building process, check them out if you’re interested.

The next steps will be to do a light sanding with 220grit paper, cut out the hatches and glue in the hatch lips and bulkheads, and then apply the polyurethane. Then it’ll be done!

Wooden Kayak Cradles

Inspired by the wooden kayak cradles made by Ross Leidy, I decided to try and make some myself. BTW, check out Ross’s great website. He’s created a free easy-to-use kayak design software package called Kayak Foundry. Amazing stuff…

I couldn’t find any 1/16″ ash veneer locally and I didn’t feel like ordering a bunch from the US. So I hunted for some 1/4″ ash hardwood for bending. I didn’t look too hard for this either and decided to get some cheap popular 4″x4’x1/4″. It was kiln dried so I wasn’t sure if I could bend it. Using a heat gun I was sort of able to bend the wood, but it had severe cracking. I opted to fill these cracks with epoxy. Next I’ll fiberglass each cradle and hopefully they will be strong enough to hold a boat.


Getting There

I made some good progress with the kayak last week. I put in fillets and taped all the seams on the underside of the deck. My friend Craig helped me ‘glass the inside of the hull, and I almost finished cleaning up the seams on the outside of the deck.

A few thoughts…
1. when ‘glassing the inside of a hull, maybe it’s best to put nice large radius fillets along all the seams. The fibreglass really doesn’t like lying down inside edges
2. black epoxy is a pain to work with
3. sanding through epoxy does not neccessarily create a halo effect. If you’re wondering why I mention this, please refer to #2 above…


Deck is stitched and glueing has begun

Call me crazy, but I decided to try and use black epoxy for the deck seams. The materials involve black pigment and microfibres from Fiber-Tek. The pigment is added to the epoxy resin up to 10% by weight. Then the hardener is mixed in. Finally the microfibres are mixed into the epoxy.

I did some tests with black pigment and fillers. The basic options for fillers include wood flour, microfibres, and microballoons (in decending order of strength). I made a batch of epoxy and split it into three separate containers. I then added wood flour to one container, microfibers to another and approximately a 50/50 mix of wood flour + microballoons in the third container. I had ruled out using microballoons by themselves for this task. I figure that the deck could see some high forces pressing down on it, and if the deck flexes I don’t want the seams to crack. Microballoons apparently are significantly weaker than the other options. The microfibres ended up maintaining most of the black epoxy gloss, while the wood flour was quite a bit dulled (as expected). The wood flour/microballoon mix was similar to the microfibres in looks, but the microfibre mix was easier to work with.

black epoxy

I’ve put the first batch of epoxy in the seams, and so far the deck looks good. I’m a bit nervous about how much work will be required to get the seams finished. I’ll need to remove the stitches and then mask all of the seams again (which is really boring). Then I’ll add the second batch of epoxy to fill in the gaps and where the first batch sagged or shrunk. Then I will have to sand all of the excess epoxy off of the panels. I’ve already applied a coat of epoxy to the panels, so the black pigment should not have soaked into the wood. Hopefully it will come off without too much work.

Laying down the glass

It’s been a busy week with the kayak. I’ve managed to do the saturation coat, lay the fibreglass and do the first fill coat. I’ll likely do some scraping on the fill coat and complete the 2nd fill coat tonight.
Overall this work went fairly smooth, although there were some stressful moments.
The saturation coat went very fast and quick. I don’t know why someone would skip this step unless they were very busy or experienced. If you have a spare day (and it seems most kayak builders do), you might as well do this step. I was making batches sizes of about 6oz, and the boat took 4 batches. There’s not much more to the saturation coat than that. Read the rest of this entry »

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