i want to paint a design on ceramic tiles. i've tried using acrylic paints on existing tiles i have but the paint does not adhere to it. can you please tell me what type of tiles i should use ie. tiles which have not been glazed, and what type of paint, and can i glaze them myself after painting the design without having to have them fired. also, where i can purchase unglazed tile and the correct type of paint. many thanks.