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How to Apply Garage Door Paint With an Airless Sprayer

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Matt is a professional painter who owns and operates his own painting business, specializing in interior and exterior house painting.


Can You Paint Metal Garage Doors?

If you're planning on painting your home's exterior, you might be wondering whether or not you can paint your garage doors. Both metal and wooden garage doors can be painted easily with little preparation if the surface is in good condition.

Repainting a faded and weathered garage door can dramatically improve your home's curb appeal and make an old door look brand new again.

Unless the door's peeling badly or really dirty, the surface preparation and painting process can usually be done in one day. I've painted dozens of garage doors over the years using different methods, but spraying is definitely the fastest and produces a finer finish that mimics the original factory finish.

Prepping Garage Doors for Paint

1. Clean the Garage

The surface of metal garage doors develop a fine powder from sun exposure and deterioration of the original paint, which is known as chalking. The chalking combined with dirt and debris from insects can cause paint adhesion problems without giving the door a good cleaning first.

Top cleaners:

  • TSP (Tri Sodium Phosphate)
  • Jomax House Cleaner and Mildew Killer
  • Simple Green Siding Cleaner

The best cleaner I've used for prepping garage doors and siding for paint is the Simple Green siding cleaner with the mildew killing additive. This product won't kill your grass or nearby plants and flowers. The Jomax cleaner works great too.

Clean your door faster with a pressure washer. With a wooden door you have to be careful not to damage the wood from aggressive washing, but this isn't an issue with a metal door.

I own and use the gas-powered Simpson MegaShot power washer for all of my exterior painting and staining projects. This washer has served me well for my painting business without any issues. Siphon your cleaner through the washer and allow it to penetrate the surface for a good 10 minutes before washing it off.

2. Sand the Door and Scrape

Do you need to sand? Scuff sanding your garage door before painting it, especially if it's a smooth and glossy metal door, improves the paint bond. Metal is non-porous and doesn't absorb paint like wood does. Sanding the metal dulls the gloss and helps the paint stick better.

You don't have to grind the door aggressively with coarse sandpaper, unless there are peeling layers of paint you're trying to remove. The best power tool to use for removing layers of peeling paint from your wood or metal garage door is the Wagner Paint Eater. All of the peeling paint should be removed through sanding and careful scraping.

For doors that are in good condition and not peeling, scuff sanding the surface with a fine grit sanding sponge is all that's needed. On metal, a 220-grit sanding sponge is good for metal doors. Avoid using coarse sandpaper that can burn through the factory finish and scratch the surface.

3. Mask Your Garage Door for Spray Painting

Garage doors are easy to mask for spray painting, using a hand masker tool. The 3M hand masker tool is your friend when it comes to masking. I use this tool on pretty much every single one of my painting projects.

Tools and Supplies for Masking:

  • 3M Hand Masker Tool
  • Painter's tape
  • Masking paper
  • Drop cloths

First, open the garage door a little, place one end of a canvas drop cloth under it, and close the door so the drop cloth stays in place when spraying.

Cover the windows on the door with painter's tape around the edges of the glass and masking paper in the middle. The door handle can simply be covered with tape. The entire door frame should also be covered with masking paper if you're not painting it.

Spray Painting a Garage Door

You can use an airless sprayer or an HVLP sprayer to paint your garage door, but I like going airless because no thinning of the paint is necessary. With an HVLP, most acrylic latex paint, especially the thick exterior paint I use, is too thick to pass through the spray gun without diluting it first with conditioner or water.

An airless sprayer is more versatile, allowing you to siphon the paint directly from any size container, big or small, instead of being stuck with the small cup on an HVLP that needs to be refilled more often for bigger projects.

My Favorite Airless Sprayers for Exterior Painting

I own three airless sprayers and use them for different types of painting projects, including garage doors. You can buy a cheap sprayer for a small project like this, but if you're looking for a dependable airless sprayer to use more than once, Graco and Titan both have some of the best sprayers, including the three below that I own.

Best Spray Tip Size

For spraying a garage door, using a wider spray tip is best because it's faster and reduces overlapping when spraying from one side of the door to the other side. When spraying a large door like this, I use Graco RAC-X spray tips in the size 515, or 517, depending on the thickness of the exterior paint I'm using. This tip produces a 10-inch spray fan. A spray tip larger than 517 will produce too much material and over-spray.

Using a tip that's too small will result in constant clogs, or the gun won't spray at all. Exterior paint is thicker than interior paint, so selecting the right orifice size for your spray tip is important. The last two digits of a spray tip number refers to the orifice size.

Spray with Lower Pressure (PSI)

  • Once you've set up your sprayer with your spray tip ready to go, it's time to dial in the right pressure. When spraying outside, spraying at the lowest pressure possible is best.
  • Turn the pressure up little by little, until the spray fan is consistent, without tailing on the edges of the spray pattern.
  • Close the door and spray it from one side to the other side, top to bottom, overlapping each pass by fifty percent.
  • Allow the paint to dry and spray a second coat.

This content is accurate and true to the best of the author’s knowledge and is not meant to substitute for formal and individualized advice from a qualified professional.

© 2020 Matt G.