When building many cars, the engine bays need to be black. After painting the cars main color. Allow the paint to cure before using masking tape and this second color. I also use it for blacked out hoods on cars. You always get consistent results using this paint. It just takes getting used the distance and speed for best results. I usually shoot about 4 away. Take your time and do multiple light coats. Make sure your masking tape is pressed down evenly so it won't seep under it. By giving light coats it helps to seal off the tape between colors.