Best way to paint a steel door

You know how some people cringe at the sound of fingernails across a chalkboard? I do the same thing when I see someone painting a steel door with a paintbrush. A steel door needs extra special care when it’s painted because the wet paint can easily be manipulated by the tool that’s applying it. When it’s on slick steel, paint doesn’t absorb into the material and “laydown” and you’re going to have a rough looking texture in your paint finish. Use these tips for painting a metal door and get a great finished product, all without putting a paintbrush in your hand!

I could make this article easy and finish it in just a few sentences. Painting a metal door? Simple. Just take it down and use a paint spray rig to coat it a few times, and then reinstall it. Problem solved, article over.

It’s true that a nice sprayed-on finish from a basic paint spray rig is the best way to paint any door, but it’s not always possible. In most cases, you don’t have hours and hours to leave the door frame wide open to the elements while you’re spraying paint from you $800 sprayer all over your backyard and the neighbor’s fence. Spray rigs are messy and taking the door out of the frame for long periods of time just causes problems all the way around.

Preparation “H”

So what do you do? You simply paint the door in place and when you’re done you close the door. Sounds too easy right? Well that’s because it is.

I’ve messed up enough metal door paint jobs to have a pretty good idea of how to do it without making it into a disaster, which it can easily turn into if you’re not careful. Over the years, I’ve developed a plan for the preparation of painting a steel door. Plans A-G were failures, but the final plan for steel door preparation, Preparation H, is a success and on the whole, feels good.

To start, you need a good exterior steel paint. The glossier it is, the harder it is to paint without a sprayer, so keep in mind a flatter paint sheen is going to produce a flatter finish on a metal door.

You’ll also want to make sure that you don’t have any issues with the old door paint. If you’re painting over an oil-based paint with a water-based paint, the water-based paint is going to peel and bubble. If you’re unsure, cover the door with a good exterior metal/wood primer first. Don’t take any chances if you don’t know, or you could end up like this guy! With my door, I had painted it last time so I knew it had a water-based coat and it was ok to paint over with another water-based exterior enamel.

Second, a good three-inch roller and roller cover are needed. Why such a small roller? It’s because the smaller roller helps to knock down any lines and it fits better in between the lines and edges of a paneled door. If you steel door is flat, by all means, use a larger four or six-inch roller.

Don’t use a roller cover with a nap bigger than 3/8-inch or else you’ll leave one nasty texture in the paint. The lighter/shorter the nap, the softer the texture and the smoother the door will look. Foam rollers work well, especially for heavier paints like glossy enamels.

I like to tape off the door parts like the hinges and door sweep to keep paint away, but I remove any other hardware with a simple screwdriver. Never use a power tool to remove any door hardware or you could end up with another project on your hands, installing a new door handle.

My project involved removing a window insert. This is easy enough if you can get a small nail or thumbtack behind the screw hole covers to access the screws. Don’t worry about the window falling out; it’s stuck on the door frame pretty good. In fact, don’t break the window or frame trying to pry it loose from the steel door!

After all that, I used an old piece of carpet for a drop cloth and made the door stationary using a covered paintbrush. This is the only time you should ever use a paintbrush on a metal door!

Last but not least, I prepped my steel doors old paint job by cleaning it with a natural degreaser/cleaner and lightly sanding the finish/removing any blemishes. Sanding the door is NOT something you want to do if your door has some age to it and might have lead paint. When in doubt, test the paint and always follow lead-safe practices.

To clean, I used a bit of oxy-something or another – it’s basically just hydrogen peroxide. It kills any bacteria, fungus and other paint eating organisms, plus it cleans the grease away while making the door nice and bright. I also used a 220-grit sandpaper to scuff the old paint up and knock down any paint bubbles or rust pockmarks. Be sure to wipe it all off with a clean damp cloth before painting.

You’ve got to Keep that Steel Door Wet

Once you’re ready to paint, just remember one thing, you’ve got to keep it wet. If you don’t keep a wet edge on a metal door when it’s being painted, the drying paint will stick to the roller and peel off. Keeping a wet edge is simple. Paint from the top to bottom of the door, going left to right and continuing the process without skipping down the door more than 4-6 inches at a time. Always keep a wet edge when painting and you’ll be successful in the final finish.

Be sure to quickly knock down any lines or paint drips that come from the corners of any impressions in the panels. If you find you’re too late, you’ll end up with a rougher texture in that area than the rest of the door. You’ve got to be fast to keep it wet!

Ideally, paint in the morning and avoid the afternoon. Early evening can work too, but not if you plan to let the door dry before closing it for the night. If the door is in direct sunlight, avoid painting until it’s in the shade. Hot steel doors are nearly impossible to paint as the paint dries almost instantly and you won’t have a wet edge to keep up with.

After your final coat goes smoothly (fingers crossed) it’s a good idea to hit it with a little more 220-grit sandpaper once it’s dry. Any rough spots that look out of place should be knocked down with some sandpaper. Be careful as you sand as you can easily tear the paint loose from the door.

You’ll also want to remove the weather-stripping around the door frame before you close the door for the first time. It can stick to a freshly painted door (even when it appears dry) and ruin your paint when you close the door for the night, so be sure to remove the weather-stripping and leave it out for the next 24-36 hours after painting an exterior door. You’ll have to deal with a little gap for a day or two, but at least you won’t have to deal with repainting your peeled door and replacing your freshly-painted weather-stripping.

Three coats should do the trick nicely, but sometimes you’ll need to do more if you make mistakes and you have to sand out your mistakes. Keep in mind; the smoother the roll is on the door, the less sanding you need to do between coats and the better the final product will look when finished. Happy painting!

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