Hi Marigo and welcome to GardenWeb. Do you plan to remove the door from its hinges or are you going to paint it in place?

Do you have a specific color in mind? Is there paint on it now that is peeling?

If you are going to do a basic color such as white, you could buy spray cans of oil-based enamel paint for metal (Rustoleum), prep the metal as indicated on the can, tape and cover what you don't wanted sprayed and go at it.

I painted my metal gutters with acrylic exterior house paint using a brush. But something tells me that you need paint that is more durable. I used an oil-based enamel paint on some metal flashing. I applied it with a brush and had some issues with even coverage.

Let's see what the pro painters here suggest.

Clean, lightly sand, clean, prime with a bonding primer( Zinnsers 123) let it dry overnight, paint

Thanks to graywings and christopehrn for their responses to my question. To graywings: the door is new so there is no peeling paint to make life miserable. I just have to change the color-from "putty" to red.

I don't like spray paint-I never quite mastered it-so I will be using an acrylic paint and apply it with a sponge brush (to minimize brush strokes). Or I will hire a painter to do it for me!

We had to paint our metal garage door that had a powder coat on it and the folks at BM recommended we use STYX first as a primer...it seemed to adhere it really well.