Kayak Construction: Gluing the seams

Today’s mission: flip the boat over and glue the outside seams.

First problem: attempting to flip the boat causes the temporary frames to move around. I have to put on a couple more beads with the hot glue gun and wait while the glue cools down. While I’m doing that, I have a look at the keel – as I saw the other day, a bunch of epoxy flowed through the gap in the keel and created these little mushroom shaped epoxy blobs. I wrote to Pygmy Boats about those the other day and they said that once the seams are all glued and the wires removed, the boat will be strong enough to sand those off. But the mushroom shape was going to cause me a problem trying to glue the outside of the keel – there were large areas with glue overlapping the keel seam but not actually touching it, and it was going to be hard to get in under them to fill the seam. So I took the easy way out – I used a Dremel tool to cut the mushrooms down, but not so close that I was risking cutting into the wood.

Second problem: the instructions say to go around the boat and push and manipulate things to straighten out the seams and make sure things look right. Mostly it was good, but there was one problem that I hope isn’t too major. The instructions say that the seams are supposed to be a nice butt joint that meets on the inside edge, with a diagram to match. (I really need to draw some diagrams here, but the only drawing tool I know how to use is xfig, which is kind of “last millenium”.) Nice in theory, but in practice, the shear seams were more like end-to-end butt joints at the bow and stern, opened up to something that looked exactly like the diagram for about a quarter of the length, and then slip into something like the bottom of a row-boat, where the side panel slips down beside the keel (man I wish I had a diagram here). No amount of pushing or prodding would make that seam look right. Oh well, hope that’s ok.

I used the provided dental syringe to lay a bead of epoxy along the three seams. It wasn’t horribly hot tonight, so it went on properly without too much flow. At this point, you’re supposed to wait 40 minutes and then apply another bead of epoxy, this time thickened with wood flour. I didn’t want the epoxy setting up in the syringe, so I decided to clean everything while I waited.

Third problem: acetone dissolves rubber gloves.

Fourth problem: I have lots of little cuts in my hands, and acetone stings like hell.

Fifth problem: I’m out of rubber gloves. So I used the rest of my forty minutes running off the store to buy rubber gloves. Wegmans has 50 rubber gloves for $4. Makes you wonder why the kit only came with 5 pairs. Ok, the Wegmans ones aren’t as good – they aren’t clear, and they don’t seem to fit as well.

I did the second bead with the wood flour. I made the mistake of cutting off a bit of the tip of the syringe to get better flow, only to discover that I was used to the amount of back pressure I got with the original tip and this new tip gave me very uneven flow. But I got it done, and then went around the boat with a squeegee and wiped up spills.

The next step is supposed to be removing the wires. But I’m concerned about the part of the seam where it’s not butting properly. I may flip the boat over and put a fillet of epoxy on the inside there. It’s not in the instructions, and it might increase the weight, but I want to be sure it’s strong enough.

If I have one consistent complaint about the instructions, it’s that they never (except the very first time) give you any hint how much epoxy to mix up for a given application. I wish they’d tell you “this will take one ounce” or “at least two ounces, maybe more”. I also wish they’d explained that the two cups they gave you are to mix the epoxy in and you can re-use them.