Fire pits provide a venue for social gatherings, and they increase the value of your home. Some fire pits are timeless; they do not wear or tarnish after years of use.
Nevertheless, many fire pits comprise metallic components that will rust after prolonged exposure to elements. When they begin to corrode, they become an eyesore and lose the appearance of a once inviting feature.
Learning how to remove rust from fire pits is a practice that every fire pit owner should know. With such knowledge, you can keep your fire pit appealing and operational for many years.
What Is Rust?
If you’re smart enough to operate equipment such as a fire pit, you probably already know what rust or corrosion is. For starters, corrosion is a type of oxidation, and it is a common reaction of metals, particularly iron, from exposure to oxygen and water.
Corrosion is not a quick process, but several factors can increase the rate of oxidation:
- Humidity
- Temperature changes
- Precipitation
- High salt composition
If you leave rust unchecked or untreated on your metal fire pits, they can accumulate holes and become unsafe to use.
Your best approach to ridding your fire pit of corrosion is to know the different types of rust. This way, you will know how they occur and what treatments to apply to them.
What Are the Different Rust Colors?
Rust can look different for varying kinds of metals and different levels of exposure to oxygen and water. If you can identify the color of the rust appearing on your fire pit, you have better chances of identifying the source.
Red Rust
This type of rust typically results from prolonged exposure to air and moisture, usually combined with a contaminant such as salt. It is most likely atmospheric, as there are minimal to zero streaks of rust on the metallic surfaces.
Instead, corrosion will look uniform across the entire metal surface. You will find this rust on your fire pit if you live near the ocean or if your location has high humidity levels.
Yellow or Orange Rust
You can easily distinguish yellow or orange rust by looking at recessed areas of your fire pit. It usually forms where high moisture is present, like a puddle or collection of standing water.
Brown Rust
Compared to red and yellow rust, brown rust is drier. It forms when too much oxygen and minimal moisture is in the air.
Unlike red rust, brown rust appears as localized, non-uniform crust spots on the metal’s surface.
Black Rust
Black rust is easily identifiable as a thin film having the appearance of a black, burnt stain. It is a result of low oxygen and low moisture exposure.
Most likely, the portion of a fire pit with black rust had something covering them for an extended period, preventing oxidation on the surface. Black rust propagates slower than red, yellow, or brown rust.
Green Rust
If you have a fire pit containing copper metal components, you will see a green patina over its surface the longer it gets exposed to oxidation. Since copper is a noble metal, it can resist corrosion due to oxidation.
The green patina works as a protective film, and the metal will only corrode if this film gets destroyed.
What Are the Four Types of Corrosion?
Aside from its various colors, rust can also fall under four different categories based on other physical characteristics.
Flash Rust
Basically, flash rust is yellow or bright orange rust. It is a form of localized corrosion when moisture or water remains stagnant in one spot.
We call it flash rust because it rapidly rusts after exposure to high moisture levels.
Stable Rust
Rust is stable when it forms more or less uniformly over an entire exposed surface. It occurs over a lifetime of exposure to low relative humidity.
Continuous exposure to moisture will result in more degradation depending on the type of metal. In some cases, designers use stable rust as a protective coating and aesthetic feature.
Flaking Rust
Flaking rust typically appears near welded joints, under a protective finish, or in regions with a break in the finish.
With this type of rust, ferric oxide usually takes up more volume than the metal it replaces. Either the thick layer of rust or the finish forms into flakes that spall off the surface.
Pitting Rust
Pitting is rust that takes the form of cracks, voids, or cavities on the metal surface. It is the most damaging form of rust found on metal objects, and it occurs when there is a localized lack of oxygen.
Without oxygen, an area gives up its electrons and accelerates the rusting process.
How to Remove Rust From Fire Pits
If you find rust on your metal fire pit, identify the type and possible source. With this information, it is much easier to pick a method of treatment or removal.
There are numerous ways to remove rust from a metal surface, but they usually fall into the following categories:
Abrasive Removal
This method refers to scraping or wearing the rusty portion away from the metal surface. While it can effectively remove rust from a metal surface, it can also do further damage.
With abrasion, you are removing the part of the metal that has already corroded, essentially thinning its layers as you go.
This method is best for flash rust and stable rust. Simple abrasion will require a piece of abrasive material or tool, such as any of the following:
- Sandpaper
- Steel or metal brush
- Aluminum foil
- A power tool that uses fiber wheels and abrasive buff wheels
Chemical Removal
The chemical removal method implies using electrolysis. It is the method of choice for stable rust, pitting rust, and flaking rust.
In electrolysis, a small electrical charge passes through the rusty metal while it soaks in an electrolyte, such as washing soda. An exchange of ions will stimulate the dissolution of rust in the electrolyte.
If you want to try electrolysis, here are the things you will need:
- A 12-volt car battery charger
- Some washing soda and water (the electrolyte)
- A cathode (your rusted fire pit metal component)
- An anode (a piece of scrap iron or steel, not stainless)
- A non-reactive container that can hold all items inside
- Some copper wire
- Some twine
- Some plastic clamps
- Some anti-rust oil
Once you have prepared the required items, follow these steps:
1. Disassemble the Rusty Item
While some metal fire pits have welded components, others have detachable parts. If you have the latter, disassemble it into smaller pieces.
Otherwise, you will need a very large container and copious amounts of an electrolyte solution to soak the entire thing.
2. Prepare the Electrolyte
Add a tablespoon of washing soda to every gallon of water and mix until the soda dissolves completely. This mixture will comprise the electrolytic solution.
3. Position the Cathode and Anode
Your rusty metal component is the cathode, and a piece of scrap iron or steel is the anode. Soak the cathode completely in the electrolyte, and leave a portion of the anode exposed to air.
You can use twine and plastic clamps to suspend the items in the solution.
4. Connect the Electrodes
Electrodes are the positive and negative connectors of the battery charger. Positive is red, while negative is black.
First, connect the negative electrode to the rusty item. Second, attach the positive electrode to the portion of the anode protruding from the water.
Don’t get the two electrodes mixed up, or you’ll have a disintegrated fire pit component and a clean piece of scrap metal.
5. Turn On the Battery Charger and Wait
Finally, move away from the electrolytic solution and turn on the battery charger. The electricity from the charger isn’t likely dangerous, but it’s always better to be safe.
Electrolysis takes time, depending on the size of the rusty metal. Watch as bubbles come off both metals and leave it until all the rust disintegrates.
6. Clean, Dry, and Protect the Cathode
Once you’re satisfied with the results, turn off the battery charger. Remove the item from the solution and clean it with a sponge, steel wool, or brush.
Since rusting will almost immediately commence after removal from electrolysis, wipe the clean metal dry and oil it to prevent further corrosion.
Items Available at Home
If you are not the most science-y person, you might not want to set up a system using electrolysis. Instead, you might want to stick to using common household items and commercially available chemicals.
Although not as effective as electrolysis, this method applies to all types of rust. Here are some of the most common items used for removing rust:
White Vinegar and Abrasive Brush
Submerge rusty metal components in undiluted white vinegar and wait for half an hour. Some rust will detach, but you will need the brush to scrub off all remaining corrosion.
Lemon Juice, Baking Soda, and Sponge
Squeeze some lemons and combine the juice with baking soda to make a paste.
Spread the paste over the affected area of the rusty metal object and let it sit for about half an hour. Use the sponge to scrub off the softened rust.
Potatoes and Baking Soda or Salt
Cut the potatoes into portions you can handle effortlessly. Sprinkle some baking soda or salt over the cut surface of the potatoes and use them to scrub off the rust from the metal.
Prevent Rust From Setting In
Now that you already know how to remove rust from fire pits, it is important to understand how to prevent rust from setting in.
First and foremost, keep your fire pit clean and free of debris after every use. Also, get a fire pit cover to protect it from rain and moisture. It is also your responsibility to inspect your fire pit for signs of rust regularly.
