Arts & Crafts How do I heat set the paint on fabrics? Use an iron set on the highest temperature appropriate to the fabric. Use a pressing cloth above and below the painted surface to avoid ink transfer to your iron or ironing board. How do I make the product permanent on glass or ceramic? Let the ink air-dry. Then over spray it with a clear coat How do I make the product permanent on wood? Let the ink air-dry, then over spray with a clear varnish or lacquer.