Wind blades are impressive structures, but they need occasional repairs. Given the expense of the structure and repair downtime, experienced repair services are critically important. The most common type of repairs is due to ice damage - as the blades are rotating, falling ice hits the blades as they move. The benefit of using fiberglass in repairs is the ease of repair and most blades are fiberglass to start with. Fiberglass is a light, strong, and corrosion-resistant material with significant fatigue characteristics, making the repair time faster. Additionally, fiberglass is non-conductive, dimensionally stable, and very low maintenance.
Working with a large construction/crane company, they are responsible for getting the blades removed and set on the ground for examination and repairs. Once the blades are all down, we set up our work area for repairs around the specific damaged areas. Items such as canopies are used to keep out the weather. Once the damage is identified, we mark out a location for the repair. First, we grind down the area until all the damage is removed, and then feather that out in a smooth transition to the original surface, preferably in a typical shape such as a square.
We add the fiberglass material in layers going from small to large, not to exceed the area we prepared, and not to add or remove weight creating an imbalance in the blade. Grinding the surface of the glass gives the resin a fresh surface for bonding. After the material is in place, we add a peel ply layer (this is a release film acting as a barrier between the actual repair materials and the consumable infusion materials used to introduce resin into the repair). All repairs are completed using vacuum infusion, which ensures proper fiber volume fraction to match OEM specification. Once the part has been infused, and the resin has completely cured, then the bagging film and infusion consumables can be removed. Then comes some sanding, fairing, and coating.