There is a saying, mostly among men for obvious reasons, that there is nothing that can't be repaired with either duct tape or a rose. But that statement overlooks epoxy, which is truly a boater's best friend.

Epoxy is known as 'the duct tape of the sea' and has more uses aboard your boat than what can be covered in this column. It not only glues things together, but it also repairs, reinforces and even finishes them. It also can replace many traditional materials and, in the process, outperforms them as well. Best of all, it's easier to use than what you would expect.

Epoxy resin is the love child of plastic developments before World War II. Shortly after the war, a commercial application called Araldite was used to create early transistors. Today, epoxies are used for everything from the structural members of high-performance jet aircraft and space shuttles to the restoration of vintage wooden boats. A petrochemical, epoxy is related to the polyester resin used in boatbuilding but has considerably higher tensile strength than polyester. Cost has been the main prohibitive factor in the construction of epoxy boats, although vinylester resin (which falls between epoxy and polyester in price) is com-monly used as an outer layer underwater to prevent blisters.

There are a multitude of suppliers for quality epoxy, but you should avoid the hardware store versions that often come in throw-away syringes and tend to be low quality. The West System epoxy is a popular brand that has found acceptance among boaters, although most expoxies are similar. It is important that you carefully read all of the instructions on any epoxy. Although the two companies are unrelated, West System products are available at West Marine and other marine hardware stores.

Epoxy is a two-part system, which means that you'll be mixing the resin and hardener together. An advantage of West System and many other brands is that the two parts are supplied in containers with metered dispensing pumps on them, providing tidier and more precise measuring.

And that is the key to using epoxy: proper mixing. With conventional polyester fiberglass resin, you can get away with just squirting some hardener into the resin, and it will still harden. Epoxy is more demanding, which is why it once had a bad reputation among those who were less than accurate in their mixing.

The mixing procedure for epoxy is straightforward and common sense. Combine the resin and hardener in the proper ratio and stir them thoroughly. First-timers might want to prepare a test batch to get a feel for handling epoxy and to help understand the curing time.

Fillers are often mixed into epoxy to thicken the material so that it can be used to build up a surface or span a gap. The most common thickening additive is microfiber, which is stirred into the resin to create consistencies like that of syrup and peanut butter. Be sure to use thickeners that are compatible with your resin.

Surface preparation is also common sense. The surface has to be clean and free of grease, oil or wax. The surface should also be as dry as possible, which may entail using a hair dryer to warm the surface first. If the surface is smooth, then it should be thoroughly abraded with sandpaper, such as an 80-grit aluminum oxide paper. Once it's sanded, remove all the dust and check again for flaking, blistering or chalking. Some surface materials, such as teak, aluminum or other epoxy, could require some additional steps to prep the surface.

The simplest project ' and the one you'll probably use most often ' is gluing things together. Two-step bonding is the best way to adhere epoxy to surfaces because it has the best penetration into the surfaces for maximum strength. In the two-step process, both surfaces are thoroughly wetted with a resin/hardener mixture (no thickeners). Then, a thickened epoxy is buttered onto one surface, and the two components are clamped securely, using enough pressure to squeeze a small amount of epoxy from the seam. As soon as the clamps are in place, you should remove the excess epoxy using a sharpened stirring stick or something like it.

Single-step bonding can be used where the joint won't have much loading and the surfaces aren't likely to absorb too much epoxy. In this situation, use minimal thickeners (just enough to bridge any gaps), and then clamp the parts as before.

You can also use epoxy to bond fasteners in place, which will dramatically improve the load-carrying capacity of each fastener. The simplest method is to wet out a screw hole with a pipe cleaner or syringe to get the epoxy deep into the hole. Immediately after this, you should tighten the screw in place.

For greater strength, drill oversized pilot holes about two-thirds the depth of the fastener, and then drill a normal-sized pilot hole at the bottom of the oversized hole. Wet out the holes thoroughly with mixed epoxy, and then fill the hole with thickened epoxy. Install the screw with enough force to hold the hardware
in place, and allow the epoxy to dry.

When mounting a flat piece of hardware to a slightly curved deck, epoxy is perfect for creating a base. Prepare the fastening holes, and bond small blocks under the base to hold the hardware in the desired position. Butter the hardware base or the deck location with a thickened epoxy, and tighten it in place. As the excess squeezes out, use a well-protected finger or a popsicle stick to shape the base neatly.

One problem often found on older fiberglass boats is a delamination of the coring. This usually happens on the deck, where water seeps in through the bolt holes for hardware and attacks the plywood core. In no time, the plywood has turned spongy, and you can feel this softness as you walk on the deck.

The starting point is to dry the area thoroughly, and then drill 1/4-inch holes that are about 1 inch apart and extend at least 3 inches past the delamination area. Your next step is to use a heat lamp or hot air gun to speed the drying process, and check the dryness by taking core samples with a drill.

Once the deck is dry, you will then mix a batch of epoxy with thickener so that it has the consistency of ketchup. Using a syringe, squirt the epoxy into each of the holes in the deck. To make sure the epoxy moves around, flex the skin as you proceed. Place weights on the deck to hold it in contact with the remainder of the core, but be sure to place a plastic sheet underneath so you don't glue the weights to the deck. Once it is cured, use a peanut buttery mixture of epoxy as filler to fair in any low spots, and then sand the deck smooth for painting.

A common problem on many boats is blistering of the underwater surfaces. Epoxy is a fine solution for this. Start by breaking open the blisters with a chisel or a grinder, and grind away all the gel coat around the damaged area. Then, dry the hull thoroughly by using heaters or fans. When the laminate is dry, sand the surface and apply a coat of unthickened epoxy to the blistered areas, followed by a thickened epoxy as a fairing filler. Once it is cured, you will then sand the surface smooth.

You can also use epoxy to protect a new or repaired hull from future blistering. Rough up the gel coat with 80-grit sandpaper to remove all glossy areas. Then, apply several coats of epoxy using a roller and, in the latter coats, stir in a barrier coat additive for complete protection. To avoid sanding between coats, apply all the layers on the same day, checking that the previous coat has started to gel before adding another. Lightly sand the cured hull, and apply bottom paint.

When handled properly, epoxies are perfectly safe. The primary hazard, however, involves contact with skin. Most epoxies will cause skin irritations even among otherwise non-allergic users, who will have a reaction similar to when they contact poison ivy. The hardener is the main culprit, but the mixed potion and even sanding dust from epoxy that has not fully cured can cause a reaction.

The safety precautions for using epoxy are simple: Wear protective gloves and clothing. Protect your eyes with appropriate eyewear and avoid breathing epoxy vapors, particularly when you are in closed spaces. If you do happen to get resin or hardener on your skin, be sure that you remove it immediately. Use a waterless skin-cleanser to remove resin or mixed epoxy since resin is not water-soluble. Hardener, on the other hand, can be washed away with soap and warm water. Although these safety caveats are very important, don't let them scare you away. Epoxy can be the solution to many boating problems.

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April 2004