A product I've used with tremendous results is from Delta Creative. It is called Ceramcoat. It is water-based and non-toxic. Also it sets up within 30 minutes and fully cures in an hour or two. You can find it on Amazon for around $6-8 an 8 oz bottle. Mix it with about 30-50% water to your desired consistency and brush it on. Clear and durable for up to 6 years they say. Some hobby stores may carry it and you may even get site-to-store at some Walmart stores. There is a slight odor but it dissipates by the time it's dry and is then totally non-toxic!