How to Quickly Rust Metal, Including Steel and Iron

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Here's the fastest way to rust metal, even if it’s galvanized

Co-authored by Carmine Shannon

Last Updated: April 6, 2024 Fact Checked

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How to Rust Metal

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Rusting Galvanized Metal

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Video

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Q&A

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Warnings

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Things You'll Need

ARTICLE

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Whether you’re a prop maker or a DIY’er, getting metal to rust quickly is easy. All you need to do is spray iron (or an alloy) with a solution made of white vinegar, table salt, and hydrogen peroxide. Don’t worry if your metal is galvanized—just use a muriatic acid solution to strip the zinc coating before spraying it down with the rusting mixture. Keep reading to learn how to get iron (and its alloys) to rust in under a day.

Things You Should Know

Spray a solution of 2 cups (470 mL) hydrogen peroxide, 4 US tbsp (59 mL) white vinegar, and 1.5 tsp (8.5 g) of table salt on a clean piece of metal to rust it.
Gently rinse the metal in water once it’s as rusted as you want it to be, dry it, then seal it with a coat of polyurethane.
For galvanized metal, you'll need to strip the zinc coating first using diluted muriatic acid.

Method 1

Method 1 of 2:

How to Rust Metal

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Only metals containing iron will rust, and some iron alloys rust slowly or not at all.^{[1]
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Research source} Cast iron or wrought iron rusts the most easily, whereas stainless steel, an alloy of iron and chromium, is more difficult.
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Make a solution of vinegar, hydrogen peroxide, and salt. Mix 2 cups (470 mL) hydrogen peroxide, 4 US tbsp (59 mL) white vinegar, and 1.5 tsp (8.5 g) of table salt in a spray bottle.^{[2]
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- If you just bought the metal, there may be a thin layer of grease on it. If so, mix hot water with a small amount of liquid dish soap, spray the metal with it, then wipe it off.^{[3]
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- If you’re using painted metal, remove the paint by sanding it down with coarse sandpaper. If you don’t want to scratch the metal, coat it with a paint stripper, then scrape it off with a straight edge.^{[4]
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For an even coat of rust, spray the metal up and down, trying to get the same amount of solution on each part.^{[5]
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Research source} If you want a more patchy look, spray some areas more than others.
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Gently rinse the rusted metal in water and then seal it. After a minute or two (or once the metal is rusted enough for you), spray it lightly with water to remove the excess salt. Let it dry completely (it may take up to 24 hours), then spray it with a clear coat of polyurethane sealant.^{[6]
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- Once the sealant dries, your rusting project is complete!

Method 2

Method 2 of 2:

Rusting Galvanized Metal

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1
Make a solution of muriatic acid and water in a well ventilated space. Mix 3 parts water with 1 part muriatic acid in a plastic container large enough to submerge your metal in. Muriatic acid is highly corrosive, and zinc releases toxic fumes when it’s being dissolved, so work in a well ventilated area and wear goggles, gloves, and a respirator.^{[7]
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- Muriatic acid, also known as hydrochloric acid, can melt or soften plastic, so use a container you are okay with damaging, and neutralize the acid immediately after using it.
  - Don’t overfill the container, or it could spill.
- Galvanized steel is coated in a thin layer of zinc to keep it from rusting, so you have to remove the zinc before you can work with the metal.
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Put the metal in the liquid, then wait for the bubbles to slow down. Once zinc touches muriatic acid, it instantly starts to boil and bubble. When the bubbles die down, that means the zinc has been eaten away.^{[8]
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- Small pieces of metal only need a few minutes in the bath, but larger pieces take longer.
- If you’re still not sure if the metal is done, check the color. Galvanized metal is dark grey, while steel is silver and shiny.
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Neutralize the metal in a solution of borax and washing soda. In a smaller container (still large enough to submerge your items) mix equal amounts of washing soda and borax into water until no more can be dissolved.^{[9]
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Research source} Put your metal in the container and soak it for a minute.
- Washing soda and borax are both bases, which cancel out acids.
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Mix the base solution into the acid solution to neutralize it. Once you’ve removed the zinc from all your metal, safely dispose of the acid by pouring the borax/baking soda solution into it. If there’s too much liquid, make a smaller batch of baking soda and water and slowly pour it into the acid.^{[10]
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- Always pour the base into the acid to avoid splashing yourself with something corrosive.
Once the zinc is gone, you can rust the metal using the first method above. Dry the metal off, then spray it with a mixture of 2 cups (470 mL) hydrogen peroxide, 4 US tbsp (59 mL) white vinegar, and 1.5 tsp (8.5 g) of table salt.^{[11]
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Community Q&A

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Question

Can it be used with metal that has a surface coating?

Community Answer

If it is galvanized you can use muriatic acid to burn it away. Use gloves and breathing mask and do it outside. Put the muriatic acid in a spray bottle and coat heavily - do not breath in fumes for health reasons. You will see it vaporize and burn off. Rinse with water and give it a light sanding or steel brushing.

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Question

Can I use a brush while using this method and not affect the painted areas?

Community Answer

You could try scotch tape or something like that to prevent the liquid transferring to areas you do not wish to be affected.

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Will this work if I use apple cider vinegar?

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It should work just fine, but it may be a bit slower. It doesn't hurt to try.

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Things You’ll Need

Rusting Metal

Vinegar
Hydrogen peroxide
Salt
Spray bottle
Dish soap (new metal)
Hot water (new metal)
Polyurethane sealant

Rusting Galvanized Metal

Muriatic acid
2 large plastic containers
Goggles
Gloves
Respirator
Water
Washing soda
Borax
Vinegar
Hydrogen peroxide
Salt
Spray bottle

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Warnings

Always exercise caution when working with hydrochloric acid or peroxide. Even in low concentrations, these chemicals can cause skin and mucous membrane irritation.

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