You need an organic vapor respirator; it will cost you about $25 at any hardware store. The problem with epoxy is allergies. You can become sensitized to it, and if you do, you won't be able to use it anymore. You need to avoid breathing the fumes, and keep it off your skin (wear gloves and a long sleeve shirt. It's hot, but I do it in the summer in south Mississippi.) When you get your organic vapor mask, you should get one that is also a particulate respirator. It will have the activated charcoal canisters (the organic vapor part) and in addition, a fabric or paper type filter that will say "N95" on it. This will also protect you from dust when sanding. It's mandatory that you not breath dust from sanding glass fibres. If you repeatedly breath dust from fibreglass sanding, you may end up with pneumoconiosis, something like the "black lung" that coal miners used to get from inhaling coal dust. When wearing the organic vapor mask, you won't smell any fumes at all. It works for working with anything that stinks I've found, no matter what it is.
Ed.