Have you ever wondered about the facts on the fabrics and resins that we use to build our model boats with? It is amazing how often we use these fabrics and resins, and not know basic information about them. For fabrics there is fiberglass, kevlar, and carbon fiber. As for resins there is polyester, vinylester, epoxy. The following information will be interesting to builders and skippers who use these items to build boats with.
Fiberglass cloth is made up of twisted strands of fiberglass woven at right angles to one another. Fiberglass cloth has been around for several decades, and it is a popular material to build boat hulls with. Of all of the fabrics, fiberglass cloth is the easiest one to work with because it does not require special techniques to lay it up. Fiberglass cloth is also popular because of its low cost and availability in stores.
Kevlar is one of the most interesting of the hi-tech fabrics. Dupont developed kevlar in the early seventies for fibers in automobile tires. Later it was discovered that kevlar, when woven into cloth and layered, can be made into bulletproof vests. Kevlar is low stretch, very strong, and very lightweight, which makes it good for building sailboat hulls. The downside to kevlar is its high cost, at times hard to work with and is difficult to obtain.
Carbon-fiber is another hi-tech fabric that is now being used in boat construction. Carbon-fiber consists almost totally of molecules of carbon bound together with resins and woven into a cloth. Carbon-fiber has enormous strength, and is very light weigh, but is prone to fracture when hit. To overcome this, kevlar is used in conjunction to allow better flexing. There has been some hulls made out of carbon-fiber, but where it really shines is when keel fins, masts, and booms are made of carbon-fiber. With it being lightweight and strong there is a price to pay. Carbon-fiber is costly, hard to get, and takes effort to lay-up.
Polyester resin is inexpensive and not very strong, It is the standard for laying up fiberglass cloth. Polyester resin has a high scent profile, not very well liked when used in the house, and messy to clean up. The upside is polyester resin is easy find, and low in cost.
Vinylester resin is stronger, more flexible, and is only a little more expensive than polyester resin. Vinylester resin is used to lay up kevlar cloth.
Epoxy resin is the strongest and the most expensive of the resins. Epoxy resin does not give off pungent odor as the other resins do. Even with the expense, epoxy resin is used to lay up carbon-fiber cloth.
Even though it is not used as a building resin, gel-coat is used when laying up boat hulls. Gel-coat is a colored resin used on the outside of boat hulls before the cloth and building resin is applied. Its main proposes is to provide a nice outer finish to the boat hull. Its drawback is weight. At one time gel-coat was used for the finish, but now on some hulls it is being left off to lessen weight of the boat.
Well, there you have it, a little overview of some of the materials we use to build our boats with. By no means is this information complete, but it gives enough information for better understanding to our hobby.