Don't let the picture of a sleek boat fool you, Meguiar's Premium Marine Wax goes on all things fiberglass, including large RVs. In fact, this wax adds an extra layer of water-repellant protection that rivals and beats many cars wax on the market today. Since it's specifically formulated for fiberglass exteriors, it is also easy to apply onto the relatively delicate surface without worrying about damage.
Coming in a 32-fluid-ounce bottle, the wax offers a lot of liquid to cover the large surface area of most common RVs. By far, the standout feature of this wax is the water-repellent capabilities it has. On boats, the wax does a great job of sticking onto the hull while fully submerged. On RVs, the protective coating sheds and beads water in rainy or snowy conditions. The wax buffs well (either by hand or power buffer) to a nice shine.
When it comes to working with the wax, the application is relatively easy, but you may find it is a bit sensitive to the surrounding environment. Like most waxes, application in direct sunlight isn't recommended. In fact, the wax's drying time greatly varies depending on the outside temperature; it has a sweet spot of around 60 degrees for good, workable drying time. Anything higher makes it dry too fast; anything too low makes it difficult to apply and remove properly.