Easy Does It: The Fiberglass Fix Is In
Fiberglass, a material made from threads or fragments of spun glass, comes in different forms.
As a building material, fiberglass is molded into hard panels, such as the corrugated ones used for patio roofs. For shaped objects, such as a bathtub enclosure, fiberglass is matted or woven into a fabric that is then bonded with resin.
Preformed fiberglass panels are easy to work with and can be cut with a saber saw fitted with a fine-tooth blade. For an outdoor project such as a patio roof, heavyweight corrugated or ridged panels are best. For indoor use or where rigidity is not necessary, use lighter flat panels. To clean the panels, hose them with water. If they discolor, apply a refinisher recommended by the manufacturer. Fiberglass panels will not bear a person’s weight; never attempt to walk on them.
Fiberglass laminate is used to make shaped objects such as automobile bodies, boats, swimming pools, bathtub enclosures and hot tubs. Layers of fiberglass fabric are bonded together with a liquid resin that cures with the addition of a catalyst, forming a tough, durable shell.
Most fiberglass repairs can be done by any handy homeowner, and you can find the materials you need at plastics stores, marine suppliers or home centers.
Holes up to one-half-inch in diameter in fiberglass laminate can be filled with putty--a mixture of resin and filler.
Larger areas are repaired by patching with layers of fabric and resin. If you suspect the damage may have affected the structural integrity of an object, consult a professional before attempting the repair.
Polyester resin, used for most laminate repairs, is easier to work with and less expensive than epoxy. One type, air-dry or tack-free, contains wax that floats to the surface of the repair, sealing off the air and allowing the resin to cure with a hard surface. The other type, air-inhibited, cures to a tacky surface unless covered with wax paper or polyvinyl alcohol spray (PVA) available in marine supply stores. PVA washes off with warm water after the resin cures. Fabric will bond better if you use air-inhibited resin for the inner layers. Air-dry resin used for outer layers will harden so that the surface can more easily be sanded.
Epoxy resin cures hard, but slowly. It is more difficult to work with than polyester. If in doubt whether to use epoxy or polyester for a repair, try a small test patch on an inconspicuous spot.
The outer finish coat of fiberglass laminate is gel coat, a specially formulated polyester resin. Wash the gel coat frequently with detergent and water and buff with wax to protect it. Scratches that do not penetrate too far beneath the gel coat can easily be repaired with a mixture of gel coat and filler, often available in a kit at marine supply stores.
Fiberglass particles can irritate the skin, eyes and respiratory system. Keep unused fiberglass filler and reinforcing material in a sealed plastic bag. Most resins and solvents are flammable and toxic. Work in an area that is well-ventilated, away from open flames. Don’t smoke. Keep a fire extinguisher rated for chemical fires nearby.
Wear clothing that covers your neck and arms as well as rubber gloves and safety goggles. When sanding, wear a dust mask approved for protection from fiberglass. When working with resins and solvents, wear a dual-cartridge respirator.
Clean up immediately after you have finished working. For safe use and disposal of products, follow manufacturer’s directions.
Don’t allow children, pets or unprotected adults in the area where you are working.
