How are plastic kayaks made anyway? Plastic kayaks are the most affordable and one of the least-breakable forms of kayak out there. Since they are made of plastic, though, you might be wondering how tough they really are. Do they have seams that can break? The answer is “no”. Plastic kayaks are made in several ways, but thankfully none of them involve seams, so if you're paddling along and crash into something, your boat isn't going to fold in half on you. (Well, unless you hit it at really high speeds—in which case, it's not the poor kayak's fault, it's yours.)
- Plastic kayaks are tough—they can be dropped without breaking, unlike a fiberglass one, and if you're careful not to drag them around on land a lot, they ought to last a very long time.
- Most plastic kayaks are made from a material called polyethylene. Polyethylene is much cheaper than fiberglass, Kevlar and other kayak-building materials, making the resulting boats cheap, too.
- By far the most popular way to mold polyethylene is rotomolding. Just like the name suggests, in rotomolding the kayak mold is heated and rotated as polyethylene pellets are dropped inside. When they hit the hot mold, the pellets melt, creating a layer of liquid plastic. The rotation of the mold ensures that the plastic's thickness turns out even and smooth.
- Because plastic isn't as stiff as other kayak-building materials like fiberglass, more layers are needed to keep the kayak from being too flexible. The added layers make the finished boat heavier than other kinds of kayak. Some variations on plastic kayak materials have a different chemical makeup so that they dry stiffer, and those are used to make light-weight but still sturdy plastic kayaks.
- If your plastic kayak isn't rotomolded, chances are it's blowmolded. Again, the name says it all, blowmolding, which uses the same polyethylene as rotomolding, is the process of making a kayak by blowing a blob of plastic into the mold. Unlike rotomolding, in blowmolding the mold itself is cold, and the air used to blow the polyethylene into it is hot. When the hot polethylene touches the cold mold, it hardens, forming the shape of somebody's future ride—maybe yours.