I am building a custom outdoor grill and bar, and am not satisfied with the typical tile countertops. After reading an article in Fine Homebuilding magazine, I would like to try building a concrete countertop. This is for my own home. Has anyone attempted this? Can I whack the form with a sledge hammer to settle out the air? How do I polish and seal the concrete afterwards? Do I need to leave an air gap around the stainless steel grill, or can I go right up against it? Will the color fade? Am I best to color it white for that reason?