How to Sand Metal (Get Rid of Metal Rust and Paint)

Knowing how to sand metal can be useful. Usually, people sand metal to get rid of an old and unwanted color from that metal or to remove any scratches.

Sanding will give the metal a smooth look and it will also make the surface even. To do that, you can either use an electric sander or sand the metal manually. We have explained how to do both. Check it out.

Can You Sand Metal?

Yes, you can sand metal. You can sand metal to get rid of old paint, metal scratches, or metal rust. Sanding metal doesn’t take a lot of effort if you have the right tools.

You can sand a lot of materials, but can you sand metal? Let's see.

Most of the time you have to sand metal before re-painting it. The metal needs to have a smooth surface before it can get painted. Another big reason why you should sand metal is to get rid of metal rust.

Metal rust can cause different problems to the metal itself. The more you leave the surface rusted the harder it will be for you to get rid of it. If you leave the rust long enough then you won’t be able to re-use the same metal. That’s why sanding a metal is important. 

Related Read — Best Sanders For Metal

Tools Needed To Sand Metal: 

  • Different Grip Sandpapers
  • Electric Sander
  • Sanding Blocks
  • Protection Gears.

You can use different tools while sanding, but the most used one and the best one is the electric sander. You can use different things to sand a metal such as the classic sanding blocks or manually sanding it with sanding paper [more on that later] but I highly recommend you to use electric sanders.

Explaining Sandpaper Grit Numbers For Metal Sanding

In this article, we have mentioned sandpapers/disks a lot. You can also see that each sandpaper has its own grit number. So, how do you know what sandpaper you need to sand metal?

  • Very Rusty Metal: 60-80-grit Sandpaper
  • Rusty Metal: 80-100-grit Sandpaper
  • To Smooth a Metal: 180-grit Sandpaper
  • Before Applying Metal Sealer: 200-grit Sandpaper

Just remember the higher the number of the grit the smoother that sandpaper is. So, using sandpapers between 35 and 100-grit means that it will remove all the top layers and unwanted material. But, you will have to be careful with these sandpapers because they can weaken the metal if you sand too hard. 

The 100-180 grit sandpapers are used to smooth the surface. You need to use these types of sandpaper only after you got rid of all the rust from the metal. Usually, these types of sandpapers are used before applying the metal seal. 

How to Sand Metal With an Electric Sander?

Here’s the guide on how to sand metal with a sander. The process can be different if you are using a different type of sander. For this example, I have used a random orbital sander. 

Step 1: Wear Safety Gears

If you are sanding metal it means one thing– you are dealing with old rusted metal. While sanding, a lot of dust is produced.  You don’t want to inhale that. That’s why it’s recommended to wear safety gear. 

I recommend using goggles and an air mask. Having gloves is also recommended because you will be touching a rusted surface. 

Step 2: Clean The Metal

Before starting to sand it, you need to clean the metal.

Before starting to sand, I recommend washing the metal. The rusty metal has a lot of dust that can get into your way while sanding.

You can use rubbing alcohol and white vinegar to clean the metal. Just put the rubbing alcohol or vinegar on top of the metal and using a wet cloth start to clean the metal. 

If you don’t have vinegar or rubbing alcohol you can use water and shampoo. This is an important step because it will help you get a better finish.

Step 3: Choose The Right Sander Type

I recommend using a random orbital sander to sand metal. Random orbital sanders aren’t as aggressive as belt sanders or grinders.

Plus, random orbital sanders have a circular movement and that’s what you need to get rid of rusty from metal. Belt sanders and grinders are very aggressive and you can damage your metal easily. 

Step 4: Choose The Right Sandpaper & Start Sanding

While sanding with an electric sander you should never use the same sanding disk to complete the entire process, to get the best results you should use different sanding disks. It’s always recommended to use the coarse sanding disk at the beginning.

You need to choose the right sandpaper. Having the wrong sandpaper can damage your metal. So, it's important to know what sandpaper you need first.

I always use an 80-grit sanding disk when I start out to sand metal, a big reason for that is because with an 80-grit sanding disk you can easily remove the top layers of paint and scratches.

But, you also have to be careful while working with this sand disk, you will have to sand slowly since you should avoid the disk from eating into the surface and weakening the surface. Once the top layers of the paint and scratches go away, you should switch to another sand disk.

Step 5: Switch The Sandpaper

You should switch to a higher and finer grit. I usually switch from the 80-grit sanding disk to the 200-grit sanding disk.

The 200-grid disk is smoother and will not eat the surface, which gives you the opportunity to get a smoother finish without limiting yourself on how fast you sand. You should use the 200-grid disk until all the rust is gone, and the metal is smooth and clean.

If there’s any space where the paint remains, or the surface isn’t as smooth as the other parts of the surface then you can manually sander that space.

You will have to go at the same steps as you would with a sand disk. Start sanding it manually with your hand by using the 80-grid sandpaper and once you are done then move to the 200-grit sandpaper.

If you want a smoother surface then you can use a ball of steel wool. It will give a smooth and unique finish. You can simply rub it in circular motions until the metal looks polished

Step 6: Seal The Metal

Once you are done you want to make sure that you seal the metal because you have a raw metal now. Apply the metal sealer and leave it to dry for a few hours. Once the sealing has dried, you can use the metal. 

And this is how you can sand metal with an electric sander. 

How to Sand Metal Using a Sandpaper?

Sanding a metal manually is the same as sanding a metal with an electric sander. It’s just a lot of times slower. 

Step 1: Choose The Right Sandpaper

The sandpaper you pick depends on how rusted your metal is. If your metal is very rusted then you should start with 80-grit sandpaper and then move to a finer one. If your metal isn’t very rusted then you can start with 100-grit sandpaper.

Step 2: Use Sanding Blocks

If the metal surface is large, then you can use sanding blocks to sand it faster.  Just take your sandpaper and wrap it around a block. Now, you only have to move the block and you will cover a larger surface than using sandpaper without a block. 

While sanding metal, you have to do circular movements with your sanding block. I recommend sanding against the grain of the metal. That way you can remove rust faster. 

Step 3: Move to a Finer Sandpaper

If you have removed most of the rust from the metal, then you can move to a finer sandpaper to give the metal a smooth look.

I use 200-grit sandpaper for this. Use the same method– wrap your 200-grit sandpaper to the sanding block and start to sand. 

Once the surface is smooth, clean the metal and then apply metal sealer. And you are done. 

Final Words

And this is, this is how you sand metal. Once you are done sanding metal you can re-paint it with another color or you can leave it with its natural metal color. But keep in mind that if you are not satisfied with the sanding then you can re-do the whole process again and again until you are satisfied.

But, make sure to only remove the top layers of paint and to smooth the metal, if you try too hard or push the electric sander too much you can weaken the metal. So always while using 30 to 100 grit sand disks try to move the electric sander as slow as possible and not push it as much.

Learn also: How to sand Tables?

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