Composite vs. Thermoformed vs. Polyethyl

Whats the difference / advantage of these three material types for kayaks: composite, thermoformed, and polyethylene

Also, anyone had any dealings with Alder Creek Kayak & Canoe Company

you should probably start with what kind of boat your budget gives you and go from there.

Thermoformed boats can be good,or overpriced for what you get. It depends on the model.

Rotomolded is the least expensive,but a $1500 kayak isn’t inexpensive.

Composite(the gamut from glass to unobtanium) tends to be lighter and is definately the most expensive.

I don’t see thermoformed as offering significant advantages unless you like that particular boat.

If your choice is between two boats and the difference in price is low enough,or the difference in features is close enough you should probably post that question first instead of a general question about materials. Otherwise the answers could be along the lines of “yellow is good”.

web site

Sorta what Lee said
Poly boats come from alloy molds. A given weight of polyethylene powder is added to the mold which is usually two halves. The halves are joined and the mold (tool) is rotated and tilted inside an oven. Some ovens are more elaborate than others. Once the cycle is complete the tool is cooled and the halves separated. The boat is removed and placed in a cooling jig before going to finishing. By nature of the material and process no two boats are identical. They are cost effective, tough, and heavy. They take more care in transport and storing to retain their shape. They last a long time, but can wear thin along the keel and can get brittle with years of UV.

Thermoformed boats are made by heating a sheet of material (usually some form of ABS, or polycarbonate) and vacuum forming it over a male tool. The deck and hull are then bonded typically by using an extruded channel and some form of methacrylate. These boats offer a stiffer, truer hull that is lighter than poly, though not as light as manufacturers often claim. The real benefit is in appearance and some performance. Generally tough boats, but can crack and weaken due to long term UV. Eddyline does a great job with this process and has further combined it with composite in what they call Modulus construction. Combines the tough thermoformed outer shell with a composite inner layer.

Composite boats are made in female molds typically and start by shooting the mold with gel-coat. Then layers of fiberglass, carbon, kevlar, core material etc. are placed in. In hand lay-ups resin is rolled through the layers as they are added. Hand layed boats can be tough but tend to have a higher resin content which equates to weight. Vacuum bagged boats utilize vaccum to remove excess resin. Infusion uses vaccum bagging and a resin manifold to draw resin through the material via vaccum. This is a techno step above just bagging, which is a techno step above hand lay-up. Pre impregnated material placed in a mold and cooked in an oven called an autoclave is a step above yet again, and this is how the skin of tomorrows jet liners is being made. Lowest resin content, lightest weight…$$$$$$$.

Different builders have varying menu’s of material in their lay-ups, and utilize these materials where they are best applied. By combining said materials you can get a light and strong kayak that is stiff and more responsive on the water, and will take a lot of abuse.

My vote is for composite, as to me it’s just more fun to paddle and own.

Composite experts may word things differently than I did, but I’m trying to give an overview…hope it helps.

Lee and Salty
Thanks guys for the info, it is helpfull. And Lee yellow IS good !!

but I like it on the bottom of the hull and not on the deck.