Build an Instant Rusted Corrugated Metal Fence

A step-by-step guide to creating eye-catching "instant rust" on your corrugated metal fence.

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Our master bedroom garden was an unsightly mess. What it needed was an instant rusted corrugated metal fence, although it took me a while to figure that out.

The space was initially designed as coyote-safe place for our small dogs and a sunny location for our raised bed gardens in galvanized stock tanks. But the native grasses had taken over, and the heavy-gauge open mesh fence offered no privacy. It was time for a serious landscaping remodel.

Bee Zollo, my life partner, and I decided we wanted a space with a cleaner, more modern aesthetic than the over-grown “natural” look that we currently had. The most important element in the new garden was making it more private. This necessitated replacing the open mesh fencing with a new design. We considered a range of wood options, but finally decided we liked the contemporary appearance of a rusted corrugated metal fence using the existing redwood framing which was in very good shape.

 

Inventing the Instant Rusted Corrugated Metal Fence

Adapting the framing to mount corrugated steel panels was relatively straightforward. But getting the rusted look was the challenge. Unfortunately, finding bare corrugated steel in our locale (Santa Fe, New Mexico) was not easy. It is not a stock item in our local big box stores.

After a bit of web-searching, I discovered a metal retailer in Arizona that could not only cut my 37 pieces to a precise length but would deliver it to my doorstep. (A word of warning to the budget-sensitive—just the raw metal for the fence came out to $2.50 per square foot of fence area.)

Once the bare corrugated steel was on order, the next test (and the real reason for this story) was determining how to accelerate the rusting process. Bare steel has a harsh industrial look, and I was concerned about the unpleasant appearance as natural rusting took several years to complete in our high-desert environment.

I headed back to the web, where I found a couple tutorials on how add a rust patina to small objects. But there was nothing about scaling the process up to handle 1,000 square feet of bare corrugated steel surface area (both sides of the panels). I needed to develop my own recipe to make this project feasible.

 

The Recipe for an Instant Rusted Corrugated Metal Fence

The basics of how rust forms is basic high school chemistry. Rust is an iron oxide that is formed when iron and oxygen react with water and/or moisture in the air. Better still, the process of creating “instant rust” is easy and rather fun—especially when you get to the last step. The materials are easy to find and the process is relatively simple and quick.

Materials

All it takes to create the “rust” part of an instant rusted corrugated metal fence is some inexpensive household chemicals, a metal cleaner and a decent weed sprayer. Specifically, you will need the following materials:

  • Degreaser: I used Zep Fast 505, but any industrial strength degreaser should work. Applied undiluted, I used three gallons for my project.
  • Vinegar: Buy this at your local grocery or hardware store. (We use vinegar for general household cleaning). Apply it undiluted. I used 3-4 gallons for 1,000 square feet.
  • Salt: Just plain old table salt is fine.
  • Hydrogen peroxide: This is available at all drug stores. Depending on the size of your project, you will need a lot of this and it’s not easy to find in gallon containers. I would estimate one gallon for every coat on 250 square feet of corrugated metal. Yes, this is a lot of the pint-sized containers typically found at drug stores. (One-gallon bottles can be ordered online.)
  • Weed sprayer: The picture below shows the inexpensive, one-gallon Home Depot brand sprayer I bought for this tutorial and some touch-up work on my fence. If your project is more than a couple hundred square feet, I spend a few bucks more for a better, two-gallon sprayer with a metal tip that lets you control the spray pattern. A nice fan pattern is much better than the random pattern that cheap sprayers deliver. As a side note, even though these chemicals are relatively mild, they can destroy a sprayer if it has metal components. So, consider the sprayer a project cost.
  • Piece of wood: This short piece of cedar is in all the pictures to demonstrate that the application of these chemicals only minimally changes the coloration of this species of wood. Other types of wood may react differently.
ingredients for a rusted corrugated metal fence project
Here are the ingredients needed to create an “instant” rusted corrugated metal fence: vinegar, degreaser, salt, hydrogen peroxide and an all-purpose sprayer.

 

The “Instant Rust” Process

The process of creating the “instant rust” part of your instant rusted corrugated metal fence takes many steps. It begins with degreasing, followed by etching, and then the instant rusting steps. Our test panel started out as a leftover piece from my project. It sat in the garage for several weeks and only picked up a tiny spot of rust in the top right corner.

corrugated metal fence panel is untreated
A panel of corrugated metal fence before the process begins.

 

Degreasing

It is important to follow the instructions for your degreaser. The Zep material was sprayed on and then rinsed off after 1-2 minutes. Do NOT try to degrease your whole project in one spray session unless you can finish all your spraying in one minute and immediately start rinsing. It’s best to do this in smaller sections.

Let the surface dry before proceeding to the next step. The degreased panel shown below is a bit shinier after cleaning. The degreaser removes minor films of dirt and oils that might affect the next steps.

Etching

This step uses the acetic acid in vinegar to start the ionization of the metal, which is essential to rusting. Do NOT skip this step or try to conserver vinegar. The vinegar is inexpensive, and etching the metal with vinegar is an important step. Spray it on and let it dry without rinsing. Visually, the etched panel has not changed noticeably.

a corrugated metal fence panel after degreasing and etching
The corrugated metal fence panel after degreasing and etching. The surface looks smoother and more uniform.

 

Rusting

Now we get to the rusting part of the instant rusted corrugated metal fence. This is my favorite part.  Mix up the rust accelerator solution in 8:1:1 proportion. For every eight ounces of hydrogen peroxide, add one ounce of vinegar and one teaspoon of salt. Stir or shake well so the salt is fully dissolved. This is very important, since salt is critical to the rust acceleration process.

Spray on the solution and you will see rust form the moment it strikes the metal. Instant rust! Apply as uniform a coat as possible, but you will likely have bare spots in your first few sections. Not to worry, since this can be corrected with subsequent coats or touch-up spraying. Below is the panel immediately after the first spraying. Notice the foaming action.

instant rusting process on a corrugated metal fence panel
The corrugated metal fence panel immediately after spraying with the rust accelerator solution. The rusting process has already begun!

 

After drying, the panel looks amazingly rusted. However, there are a few spots that didn’t rust thoroughly, and the rust is not uniform.

the instant rusting solution has dried on the corrugated metal fence panel
After the first coat of the rusting solution has dried, the color of the corrugated metal panel looks much more uniform.

 

To improve rusting coverage, a second coat of the rusting solution was applied and permitted dry. Now, the color is much more uniform. (NOTE: You may also be able to get this “second coat” look simply by doing a touch-up spraying after the first coat.)

A corrugated metal panel after the second coat of rusting solution was applied
The corrugated metal panel after the second coat of rusting solution was applied and dried. The rust is much more even.

 

My Instant Rusted Corrugated Metal Fence

After less than a month, I am really pleased with the results of my instant rusted corrugated metal fence project. My actual fence is only a one-coat effort, which I will touch up in several places as the landscaping portion of the project wraps up.

Even if I do nothing, I expect the rust coat will naturally develop a more uniform appearance over the next year. I think it’s worth 30 minutes of mixing and spraying to accelerate the process nicely.

a rusted corrugated metal fence at a Santa Fe home
The finished fence has a nice rusted appearance. The instant rusting process mimics what Mother Nature does to metal–but it doesn’t take many years to get the desired result.

 

Bonus Tips for your Instant Rusted Corrugated Metal Fence

  • Common sense safety is the most important factor in an instant rusted corrugated metal fence project. Even though these household chemicals are mild solutions, wear gloves and eye protection.
  • Do NOT buy Corten-branded corrugated steel if you use this process. Corten products are at least 25% more expensive than bare steel and the rust acceleration process described here delivers a similar result. If are patient and would rather not deal with the “instant rust” process, by all means consider Corten corrugated metal. It is manufactured to deliver a nice uniform rust coating in as little as six months with minimum fuss.
  • The test panel in this article received three coats of the rust accelerator solution. For small projects or impatient folks, three coats might make sense. For larger projects, I would recommend a good first coat with coverage as complete as possible. After that coat dries, hit the bare spots with more rust accelerator solution and then give it a few weeks or months to see how it looks. Touch up again if necessary or know that time is your friend in this process. Unprotected steel in an outdoor environment will rust eventually.
  • In my project, I diluted the rust accelerator solution by adding water in the same amount as the hydrogen peroxide and doubling the salt. It left bare spots which I plan to touch up. So, if you decide to use a diluted solution, plan on doing two coats of spray. I think the best approach is to use the proportions I outlined above for the first coat and do a bit of touch up spraying. It saves time and uses about the same amount of hydrogen peroxide.
  • Do NOT try to use galvanized panels to save money. This process WILL NOT WORK on galvanized surfaces for the obvious reason—galvanization is a rust inhibitor.
  • If you are tempted to let nature take its course in rusting the metal panels, plan to be very patient. The picture below is the backside of a section of the fence that wasn’t treated. After a month, very little rust has formed—even after several spring rain storms. This section is somewhat protected and does not receive direct sunlight, but the complete lack of rust suggests there may a light film of oil from the rolling process that is protecting the surface. Over time I’m certain it will rust nicely, but it could take a couple years.
An untreated corrugated metal fence
An untreated corrugated metal fence shows almost no sign of rust after 30 days in the landscape.

 

That’s it! Enjoy your Instant Rusted Corrugated Metal Fence, and please leave comments and questions below. Click here for Other Fence Ideas.

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