Most vessels and yachts built these days are built of fiberglass. A fiberglass boat is made of resins and synthetic glass plastic matting merged together to strengthen it. The outside boat areas are constructed of layers of colored resins known as gel coat. Gel coat is the material used to give the high-quality texture on the visible surface of the reinforced material beneath.
What’s Gel Coat?
The most common gel coats used with today’s vessels are structured on polyester resin chemistry. Gel coats are resins which are put into casts in the liquid state. The constructed module, when satisfactorily cured and taken from the cast, makes the gel coated surface. Over time, these gel coated surfaces can be damaged and dinged from age. The sunlight can also generate small cracks, but repairs can be made.
Here is how I do this. Topside gel coat cracks can be polished out of a gel coat exterior with automotive polishing compound and good old elbow grease, but deep scrapes must be filled. Excluding shade matching, gel coat repairs are relatively easy and uncomplicated. If cracks are deep, I normally prepare them for repair by grinding the surface with a Dremel tool. This provides suitable bedding for the resin. I prefer to utilize the West System epoxy for making my repairs.
The success of the repairs relies upon not only the ability of the epoxy’s strength, but also on how effectively the epoxy adheres to the facade being put on. Except when you are bonding to partially cured epoxy, the potency of the union depends on the epoxy’s capability to “affix ” to the topsides. The next three steps of surface preparation work are an important part of any epoxy gel coat repair.
For top-quality bonding, all surfaces have to be:
1. Clean – All surfaces to be fixed have got to be free of all contaminants like grease, oil, wax or silicone. Wipe all surfaces with a fresh cloth moistened with lacquer thinner or acetone. Wipe the surface before the solvent dries. Cleanse the entire surfaces before sanding or grinding with a Dremel tool to avoid rubbing the pollutant into the current fiberglass face.
2. Dry – All topsides must be as dry as possible for high quality bonding. If necessary, quicken the drying by heating the topsides with a blow dryer. As always, epoxy is not going to stick to moist surfaces.
3. Sanding – Sand flat all surfaces- carefully rubbing each surface. Get rid of any cracking, chalking, blistering, or previous paint coatings prior to sanding. Remove all airborne debris following sanding with a rag dampened with solvent.
Fairing refers to the filling and shaping of ground out areas so they merge with the adjacent areas and appear “fair” both to the eye and touch. Prime the area like you would for bonding. Sand away all bulges and bumps on the surface and remove all dust from the surface to be faired afterwards. Combine resin/hardener and fairing filler to a putty-like thickness in accordance with the manufacturer’s directions.
Always add fillers in a two-step manner:
1. Blend the preferred quantity of resin and hardener thoroughly before adding fillers.
2. Mix in small amounts of the suitable filling until the desired thickness is reached; be cautious not to put in too much.
Be certain all of the filler is totally mixed before the mixture is applied. Spread the mix into a thin layer in the mixing container to extend its working life; thick blended resin will become hard rapidly. The epoxy blend can now be troweled on with a plastic squeegee, pressing it into all spaces. Flatten the mixture to the desired form, but leaving the epoxy a bit more elevated than the adjacent area. Remove any spare thickened epoxy prior to it beginning to age. In addition, if any holes are more than ½” deep, apply the epoxy mixture in multiple applications. Let the final thickened epoxy treatment age completely. Drying will take anywhere from one hour or more.
Smooth the applied fairing matter to merge with the adjacent contour; larger grit sandpaper will remove more material as you sand. Conclude with smaller grit sandpaper when you are close to the last contour. To complete the task, I prefer to paint the repaired surface.
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