The gel coat is applied to the surface which was coated with a release agent before. Edges and breakthroughs should be pre-coated thinly at the beginning. So air entrapments can be avoided. After the surface is dry to the touch (i.e., no build-up on the finger or threads are pulled), the second layer of gel coat is applied. Two layers of gel coat are recommended for you to achieve a higher layer thickness. This is very important in subsequent work, such as grinding or polishing.