How To Remove Paint From Metal

When newly applied, paint can apply an opaque sheen to metal components. However, it tends to degrade over time, resulting in a dirty-looking surface. Painting over it isn’t really an option, as any imperfections will carry through into the new coat as well.

Fortunately, there are ways to remove paint from metal without too much effort, leaving the surface as sleek as it was when it left the manufacturer. Choosing the best method will largely depend on the item being treated, so in this blog, the team at Red Label Abrasives will explain how to remove paint from metal without too much time, effort, or risk of damage.

Tools

Depending on the method you choose, you’ll need the following tools and accessories:

• Surface protection in the form of plastic sheets, newspapers, drop cloths, or similar items
• Safety goggles
• Dust mask
• Heat-resistant gloves
• Chemical-resistant gloves
• Paint scraper
• Putty knife
• Disposable pan or pot
• Tongs
• Hard-bristled brush
• Paint stripper
• Disposable container
• Clean rags
• Mineral spirits

Mechanical Paint Removal

Mechanical paint removal involves the use of tools or manual force to remove paint. As abrasive manufacturers, we're inclined to prefer this form of removal.  These methods can be used on any metal surface and allow you to remove paint without dealing with harsh chemicals. Mechanical paint removal has a higher risk of surface damage, so extra care and caution are needed if using one of these approaches. 

Paint Scraper

The paint scraper is ideal for flat surfaces and small jobs where the paint will come off without using chemicals. If you're working with a softer metal, such as brass, choose a plastic blade over a metal one to avoid damaging its surface. Choose a scraper that's comfortable to hold and suitable for the job (a wide blade for flat, wider surfaces and a narrow blade for smaller, difficult-to-reach areas).

Angle Grinder

If you’re working with more robust metal pieces like pipes, metal furniture, and larger flat surfaces, you can use an angle grinder to remove the paint. 

The job can be accomplished using a variety of grinder attachments. Wire wheels are very effective, but they also throw off the most debris. Therefore, it's best to start with a less aggressive approach. Try flap discs, which are available in a variety of grits. Depending on the results, you can always switch to a coarser grit or wire. Red Label manufactures high density EdgeCore Ceramic Flap Discs, which work great for removing paint and are some of the longest-lasting flap discs on the market. 

Closed coat aluminum oxide, zirconia, and ceramic will all work for sanding paint off of metal. Ceramic delivers the most aggressive cut and the longest lifespan, so you’ll get your money’s worth when you use ceramic discs for metal sanding. 

Orbital Sander

An angle grinder isn’t the only abrasive tool you can use to remove paint from metal. You can also use an orbital sander with metalworking sanding discs. Orbital sanders are some of the most common tools used for sanding paint off of metal surfaces, especially for auto body work. 

You can start with an 80 grit sanding disc for the initial paint removal, but you’ll want to switch to a 180 - 220 grit sanding disc once most of the paint is off. If you continue to sand with an 80 grit disc after most of the paint is removed, you can accidentally sand into the metal too much and weaken the workpiece. 

You can use sanding sheets in combination with your orbital sander to sand tight spaces and corners. You can create a smooth finish on your metal after sanding by rubbing steel wool across the surface in a circular motion. 

Paint can gum up sanding discs very quickly. You can quickly restore your sanding disc with a disc cleaning eraser stick. 

Chemical Paint Removal

As the name implies, chemical paint removal processes utilize chemicals to break down paint bonds. Chemicals will loosen the bonds, but they won't completely remove the paint. Chemical methods will need to be combined with mechanical techniques. Chemical methods can be a good option if you're working with large or intricate surfaces, or metal surfaces with stubborn paint layers that aren't coming off with other methods. 

Paint Stripper

Paint stripper may be your best option for large metal pieces or those coated with spray paint. Before using this method, ensure that the area is well-ventilated and that any potentially flammable items are removed. 

Fill a glass or metal can with a small amount of the stripper. Chemical paint stripper should be applied to the metal using a disposable paintbrush, and let it set according to the instructions. You should see the paint bubble up from the metal surface as it sets.

Take a paint scraper and scrape off the bubbled paint from all the metal's flat surfaces. Switch to a nylon brush or scrubbing pad for crevices and harder-to-reach areas. The stripper should be reapplied and scraped or brushed away as needed until all the paint has been removed.

Next, dampen a rag with mineral spirits and wipe the surface to remove any leftover paint flakes and the bulk of any chemical residue. Finally, rinse the metal thoroughly with water to completely remove all traces of the stripper, then wipe it down with a fresh, dry cloth.

Baking Soda / Vinegar and Heat

If you’re working with smaller items like hardware or door hinges, mixing baking soda and water or vinegar and water over a heat source is a natural way to remove paint from metal surfaces. This can be done on your stovetop with a disposable pan or pot. Add 1/4 cup of baking soda or vinegar to each quart of water and bring to a boil. Place the item in the pan and let it boil for about 15 minutes or until the paint falls off. Put on heat-resistant gloves and remove metal pieces with tongs. Use a hard-bristle brush or putty knife to scrape off any remaining paint.

Mineral Spirits

If you'd like to avoid harsh paint stripper, you can skip the stripper and go straight to using mineral spirits. Mineral spirits will help to remove the paint but usually require more effort than a paint stripper. 

Start by applying mineral spirits to a clean rag. Rub the rag across your painted metal surface. The mineral spirits will begin to break the bonds of the paint molecules and gently dissolve the paint. Once the spirits have been applied to the entire surface, you can use a second clean rag to wipe away the loosened paint. 

The paint likely won't be completely removed with the first application. You can repeat this process until all of the paint has been removed. 

Natural & Eco-Friendly Paint Removal

For those with chemical sensitivities or a concern for the environment, there are more natural and eco-friendly methods of paint removal that you can try. They tend to prolong the paint removal process, but they can still get the job done with some added effort. 

Citrus-Based Paint Removers

Citrus-based paint removers use a solvent derived from citrus peels (d-limonene) to break down paint bonds. These removers are biodegradable, provide a pleasant citrus smell, and can be non-toxic (some are still made with harmful chemicals). 

Start by generously applying your citrus-based paint remover to your painted metal surface. Allow the application to sit for the recommended time provided by the manufacturer (typically between 30 minutes and 1-2 hours). 

With the paint bonds broken, you can then use a scraper or putty knife to remove the loose paint. After removal, the surface should be cleaned with water or mineral spirits. 

Soy Gel Paint Strippers

Soy gel paint strippers are biodegradable strippers produced from soybeans. They're low in volatile organic compounds and generally considered non-toxic, but they can still be harsh on the human body. Soy gel paint remover can still cause eye, skin, or respiratory irritation and shouldn't be used without proper protective gear and adequate ventilation. 

You can start the process by applying a generous layer of soy gel stripper to the painted metal surface. Once the gel is applied, it should be covered with plastic wrap to prevent the gel from drying out. Let the application sit for several hours or overnight to allow the gel enough time to break the paint bonds. 

After an adequate amount of time, you can remove the plastic wrap and scrape the loosened paint off of the surface with a paint scraper or a putty knife. Much like using a traditional paint stripper, you'll want to finish by cleaning the metal surface with water or mineral spirits. 

Heat-Based Paint Removal

Applying heat to your painted metal surface can relax the paint bonds. However, too much heat can also warp or damage metal. Heat-based paint removal can be effective, but caution should be exercised to protect the metal surface. 

Boiling Water

For smaller items, boiling water can remove paint. Put the metal item in a heat-resistant container. In a kettle or teapot, boil water until it reaches a rolling boil. Pour boiling water slowly over the hardware, submerging it.

Wait until the paint begins to bubble before removing the hardware from the boiling water tray. In most cases, this will take about five minutes. (If the paint doesn’t bubble, drain the pan and repeat the process with more boiling water.) As soon as you notice the paint peeling off, put on heat-resistant gloves and carefully scrape off the loose paint while the hardware remains in the container. As a final step to remove dirt, grime, and tarnish, use a lint-free cloth.

Heat Gun

Using a heat gun melts the paint, allowing it to peel off the metal. Put the heat gun on its lowest setting and hold it a few inches from the surface, moving it slightly back and forth. Start slowly and avoid overheating the area. When the paint begins to bubble or pull away from the surface, scrape it off with a paint scraper or putty knife. If the paint does not bubble, gradually increase the temperature until it does. Use heat-resistant gloves and wait until the metal has cooled completely before touching it.

Tips for Better Paint Removal

• You can use old toothbrushes to clean hard-to-reach corners and crevices.
• Coarse grits below 80 and brushes with wire-bristled bristles should not be used on metal; otherwise, they may pit or damage the surface.
• Follow the paint stripper's instructions and leave the chemical on the metal for the recommended amount of time. 
• Using mineral spirits and a clean rag, clean the item after all paint has been removed.
• Ensure that paint, chemicals, and materials are properly disposed of.

Best Practices for Safety

Use the following safety measures when removing paint from any surface:

• When working with a chemical paint stripper or angle grinder, make sure you are working in a well-ventilated area (outside, if possible).
• When working with chemicals, wear gloves and a face mask to avoid potentially dangerous contact.
• You can test your metal piece for lead if you suspect the paint contains lead (which is possible if it was applied before 1980). If the test is positive, protect yourself appropriately and use a removal method that wipes off the paint and disposes of it immediately, rather than grinding or dry scraping, which creates dust and airborne particles. It may be safer to call in a professional to remove the paint.

Proper Disposal Of Paint Residue 

Dried latex paint can be safely discarded in your regular trash can or dumpster. However, oil-based and lead-based paints are considered hazardous waste and should not be disposed of in your trash. 

You should contact your local municipality to determine how to properly dispose of hazardous oil-based lead-based paint waste. Do not attempt to burn the paint. Burning paint can release toxic fumes. To prepare for disposal, you should also collect all paint chips and residue in a plastic bag that you can seal to keep the waste contained. 

Unless you're absolutely sure that latex paint was used on your metal surface, the best approach for disposal is to assume that the paint is oil-based and dispose of it accordingly. 

Red Label Abrasives: A Cut Above The Rest

When you’re working with larger metal surfaces, your best option may be to grind away any built-up paint. Red Label Abrasives manufactures metal sanding discs and flap discs that can remove paint without damaging the metal surface underneath. We also produce sanding belts, discs, sheets, and accessories that reflect almost four decades of experience in the abrasive industry, so if you need abrasives for general or specialty applications, we can help.

If you have any questions about our products, need any assistance, or would like to place an order, call 844-824-1956 or fill out our contact form and we’ll soon be in touch!