You can get the activator at West Marine or any marine store. As for filling chips, trick is patience. I mix very small batches (2-4 tablespoons of gelcoat) at a time in a disposable container like a yogurt cup (be careful disposing, it gets very hot when curing). Apply a thin layer with a brush ( I use brush for painting plastic models like when we were kids), cover with wax paper and let dry. Then repeat until you build up to a little above level of surrounding surface. Then sand using various grits. If you do a search in the Forum, there are some real detailed instructions on how to proceed. Good luck.