Fiberglass is very tiny fibers of glass (Duh!). Although almost certainly seen before by glass blowers, in 1932, Dale Kliest at Owens-Illinois tried to weld together glass blocks and when a jet of air hit the molten glass, glass fibers were formed. Later, in commercial use, steam was used instead of air. In the 1930s Owens of Illinois expanded and later combined with Corning Glass to form Owens-Corning. In 1936, Fiberglas (one 's') was trademarked and patented. Although used for insulation, the companies began research on spinning the fibers into cloth and introduced a heat treatment to give the cloth more flexibility. In 1942, Owens-Corning partnered with the USAAF to develop plastic laminates made of fiberglass cloth impregnated with resin and in 1944 the first fiberglass-reinforced plastic boat hull was made eventually followed by fishing rods, kitchen trays and finally pleasure boats. In 1953 they worked with GM on the fiberglass-bodied Chevrolet Corvette. Nowadays fiberglass reinforced plastic is used to make most boats and RVs, some specialized cars, shower stalls, bathtubs, hot tubs even swimming pools and park water slides. Fiberglass items are made in a female mold with a smooth inner surface covered with a wax/silicone based 'release agent' . This stops the resin sticking to the mold. When a boat is made of fiberglass, mat and woven glass fiber layers are 'layed up' one at a time by impregnating with a catalyzed resin.). Polyester resin is most commonly used, but sometimes other resins. These include epoxy (more expensive but tougher, more adhesive for bonding purposes and much more water resistant) or polyvinyl ester (properties between those of polyester or epoxy - much better for underwater surfaces). Also Kevlar or carbon fiber may be used for reinforcement of the resin with a great increase in strength to weight ratio. Kevlar (the aramid fiber used in bullet-proof vests) is sometimes used in the lay up around bows to minimize future collision damage. Carbon fiber is commonly used in things that have to be light and strong such as spars. Vacuum bagging is used in making spars to make the lay up free of air bubbles with a much denser and stronger laminate. Sometimes the glass fiber is sandwiched with other materials (balsa, plywood, plastic foam) for added strength or lightness. The outer finish is usually composed of resin containing colored pigment. This is called gelcoat and is sprayed into the mold before laying down the layers of resin-impregnated fiberglass. The gelcoat stripes on the boat are applied separately and are usually very thin compared to the main gelcoat coating (more about that later) Because the smooth inner surface of the mold is coated with a wax/silicone mold release agent, when the boat is removed from the mold it is already shiny- just like a new car and has the outer color of the gelcoat. This process makes boats cheaper to manufacture as anyone who has had to have a car or boat spray - painted with polyurethane will know. However the gelcoat is not as durable as polyurethane paint, which is more flexible and less prone to cracks and is much less prone to oxidation and staining. Aging of the gelcoat finish Gelcoat ages by a sort of plastic rust called chalky oxidation. The chalk is made of oxidation breakdown products of the polyester gelcoat. Because the long chain polymer chains are broken into smaller and smaller pieces, the eventual process yields chalky material - sort of analogous to surface rust. There will also be some partially oxidized material that is softer than the original gelcoat and often of lighter color (the pigment may fade in the sun). Although surface oxidation is fairly easy to remove, it can eat down into the gelcoat (again, like rust on iron). Indeed, this oxidation forms pores or 'microcrevices' that are full of chalk and therefore increase porosity of the gelcoat. This chalk absorbs stains (e.g. rust, diesel smoke) and makes white gelcoat lose much of its pristine look. Repeatedly using strong acid cleaners (including oxalic acid) tends to 'eat out' these microcrevices making the gelcoat even more porous. Gelcoat can eventually become so porous that it can no longer be made to shine by conventional compounding and waxing. Furthermore, on black or dark colored gelcoat, the whitish chalk in the pores also makes it impossible to restore full depth to the color, even with much compounding Maintaining and restoring the gelcoat finish Superficial oxidation is easily removed by an abrasive compound ideally followed by polish (finer grit than compound, higher shine) and then sealing the finish with wax. This process does also remove some of the good gelcoat and can only be done so many times. Also, the thin gelcoat of the gelcoat stripes and its edges are very susceptible to being 'burnt through' by the buffing process. However ISLAND GIRL Cleansers can selectively dissolve off the chalk without affecting the gelcoat itself - this is because the small molecules of chalk and partial breakdown products are more soluble than the long chain polyester polymers of the gelcoat itself. By contrast a non-selective solvent (acetone) will dissolve both chalk and polyester. In our view compounding should be reserved for removing excessive roughness of the gelcoat (that can reduce shine) and for removal of any superficial layer of gelcoat in which the original pigment has faded. Another drawback to use of abrasives (again in analogy to iron surfaces), is that the process of producing microscopic scratches (i.e. polishing) can actually speed up the oxidation process by increasing the surface area of 'raw' gelcoat susceptible to oxidation. This happens because wax may seal against water but not the air needed for oxidation. What about dark colored gelcoat that remains 'grayish' in color or gelcoat that is so porous that it will no longer take a shine. In the old days (and some people still remain there) the only answer was to wet sand down into the gelcoat (hopefully to reach 'bottom' of the pores) and then polish and wax, obviously thinning down the gelcoat and failing to remove all of the deep-down oxidation. Again, like rust on iron, this deep-down oxidation acts as the seed for more oxidation. The first alternative to these old ways was to clean the gelcoat and then seal it with an acrylic based fiberglass restorer that soaks down into the pores. Best results are seen with a professional solvent-based acrylic or even a two part clear polyurethane, after thorough cleaning and wet sanding of the surface. However there are also several owner-applicable products that are water-based acrylics (originally developed from kitchen floor sealants). At their best, these finishes can give very satisfactory and very durable results because they do seal off the pores from air better than wax. However, in our view it is ESSENTIAL to first remove all chalk and wax, ideally wet sanding too to provide a key, otherwise the finish will inevitably flake off (it is a hard brittle coating). Generally these finishes are not recommended for new gelcoat. Also, since acrylic coatings become yellowed with age, they should be used judiciously on white or very light-colored gelcoat. Possibly this would not be a problem with old, porous gelcoat treated with our fluorescent SEA GLOW™ product (some of which would combine with the coating) but we have yet to test this possibility. Undoubtedly, such coatings have their place but can only be thoroughly removed by ammonia-based strippers and wet sanding down into the pores. Water based acrylic coatings also require about six coats applied with a special applicator and (being water based) can only be used in dry conditions on a boat that has been hauled out of the water. Our ISLAND GIRL® Cleanser/ Conditioners (CLEAR™or SEA GLOW™) are designed to dissolve out allof the chalk from deep down and then draw it up to the surface into paper towel soaked in the product. As the product dries back, the gelcoat draws the clear and inert polymeric conditioner down into the pores adding reflective depth. Since the conditioner contains anti-aging preservatives (anti-oxidants, free radical scavengers, inhibitors or mildew and algae growth) the oxidation process is halted or considerably retarded. In addition, the conditioner of our SEA GLOW™ product contains strong fluorescing agents to 'light up' white and bright colors in response to the UV in sunlight while diverting it away from harmful free radical formation. With SEA GLOW, it can be seen that the tables are turned and UV actually makes the plastic look better and reverses the aging process! Finally the surface is sealed by our SIMPLY BRILLIANT Superwax that being both wax and resin based forms a sufficiently thick and dense coating to prevent oxygen penetration. Protection of both the Superwax and the gelcoat is further enhanced in our latest version that contains additional anti-oxidants. The Superwax™ is wiped on in 1 or more coats using white paper towel and can be applied to a boat in the water under less than ideal conditions from the dock or from a dinghy (see tip of the month below). WANT TO SEE DIAGRAMS? CLICK ON <http://www.islandgirlproducts.com/newpink.html. Repair of Gelcoat gouges and cracks. The final problems that can happen to gelcoat are nicks, scratches and stress cracks. The polyester resins of the gelcoat slowly become more brittle with age and are therefore more prone to stress cracks. The latter tend to form around metal fittings due to alternative heat expansion/contraction. They also form (as on my boat) in some areas where the boat has hit the dock a bit hard and the fiberglass hull flexed. Because the gelcoat has no fibers for reinforcement, it is less flexible and may form some surface cracks or crazing. Procedures for fixing such blemishes will be dealt with in the next issue of this newsletter. Osmotic Blisters Of course the main worry with fiberglass boat hulls is penetration of the gelcoat by water below the waterline forming 'osmotic blisters'. This topic also will be addressed in a future issue of this newsletter. NOTE: THE ABOVE IS ONLY AN INTRODUCTION TO A COMPLEX SUBJECT. FOR DETAILED ADVICE ON FIBERGLASS REPAIRS AND CONTRUCTION GO TO THE EXPERTS AT THESE WEB SITES AN/OR CALL THESE NUMBERS: http://www.tapplastics.com/ ; http://www.fiberglast.com/ ; Fiberglass Hawaii (Honolulu 808 847 3951, ask for Ted Wilson; Santa Cruz: 831 476 7464, ask for David Collingnon).