If you have a cast iron fire pit, you might be wondering if it’s capable of rusting, or you’ve noticed spots appear on it already. This can be frustrating, especially if your fire pit is fairly new.
Rust can happen anytime there’s iron alloys present, so it’s quite easy for it to happen on your metal fire pit. It’s so easy, in fact, that even five minutes is long enough for rust to start forming on metal surfaces.
The exposure to the elements is what makes fire pits so uniquely prone to rust. And heat only speeds up this process. So, it’s no question why cast iron fire pits are so easily rusted out.
Although you can’t totally prevent rust from forming on a cast iron fire pit, the best way to protect your cast iron fire pit from it is to perform regular maintenance and to shield it from the elements as best as possible.
What Type of Rust Am I Dealing With on my Cast Iron Fire Pit?
There are four ways that rust presents itself on iron oxide, and that will dictate what method you use for getting rid of it.
Pitting rust only really happens on low-quality metals that have air trapped inside them. It attacks the metal from the inside and is the worst kind of rust you can have. Luckily, this doesn’t happen on fire pits. It’s the other three that you have to deal with.
Flash rust is the first type you’ll see appear. It’s the “beginning stage” of it. It looks like dotted or liquid rust and it happens extremely fast, sometimes within minutes. Fortunately, it’s quite easy to get off and will keep the problem from getting worse once you do so.
Flaking rust happens once the oxide in the iron has expanded to the point where the layers are able to corrode away one at a time. It’s easy to peel off but it requires a lot of elbow grease to fully remove the thicker layers of oxide.
Lastly, there is stable rust, which happens after the rusting process has gone on for a long time and it’s spread to most of the metal surface. Old cars in junkyards are perfect examples of stable rust that appears on ignored metal. It’s pretty hard to remove, but not impossible if the damage isn’t too extensive.
What’s Wrong with Rust on your Fire Pit?
Besides looking ugly, getting rid of rust on your fire pit is important because it can be really dangerous if the damage is severe enough.
Most rust issues can be buffed out using elbow grease and some chemicals, but significant rust is impossible to fix. It’s important to know when that occurs so you know whether or not to toss it out.
First, the rust could have warped the iron to the point where sharp edges are exposed, potentially scratching or cutting someone. This is an indication that the rusting has progressed too far.
There’s a common belief that stepping on a rusty nail leads to tetanus, but it’s the bacteria already present on the nail that causes it, not the rust itself. However, this means that rusted areas have enough bacteria on them to make you sick if it causes a wound, so pits with sharp edges are a health hazard.
Secondly, the rust could have done enough damage that holes have appeared on the metal. This can be extremely dangerous if a fire is present, as embers and hot ash can fall through the holes and either injure someone or cause an additional fire to break out. If you can see through the bottom of your fire pit, it’s too far gone to be repaired and should be tossed out.
This is why it’s so important to address rust issues as soon as they appear on your fire pit. If you can fix it before it gets too severe, you can enjoy your fire pit for much longer.
How to Fix Rust Damage on your Cast Iron Fire Pit
If it hasn’t gotten that bad, you can get rid of the rust on your fire pit to make it look like new before going through the prevention process.
To do this, you will choose either a manufactured rust remover or a natural-based one.
Chemical-based rust removers work really well but they require extra safety precautions before using. Make sure to read the manufacturer’s label and work in a well-ventilated area before applying the product.
No matter the type of remover you use, make sure to thoroughly clean your fire pit with hot, soapy water first. Some people use steel wool or an abrasive brush to do this as it also begins to get rid of the rust, but it can cause scratches and other abrasions to the stainless-steel finish that might make it look dull or old. Consider gentler methods of scrubbing.
Make sure to dry the fire pit completely before moving onto the next step. Absolutely no moisture should be present.
For chemical-based rust removers, simply use a medium-sized paintbrush to apply the solution to the rusted areas. Check the manufacturer’s label to see how long to let the product sit; most of them are around 15 minutes.
Rinse the remover completely off of the pit after the right amount of time has passed. If there’s still rust present, you can repeat the process multiple times.
Fully dry the fire pit after treatment or rust will quickly reform!
It’s easy to get rid of rust using natural alternatives to chemical-based rust removers and they do a good job as well. The key is high acidity.
The 5 items below will get rid of minor rust on your cast iron fire pit. Some of these might be odd, but they’re proven to work!
- Baking soda
Baking soda works great for removing rust because it’s abrasive and scours away rust particles from surfaces. It’s best to use on minor rust stains. Simply make a paste with baking soda and water and apply it onto the rusted areas. Wait one hour before using a toothbrush or scrubbing pad to gently scrub the paste into the rusted areas. Rinse and dry the area completely after scrubbing.
Vinegar is a common way to get rid of rust and it works great because it’s extremely acidic. You can pour it directly onto rusted areas, or you can soak a cloth and place it against the areas. Let it sit for 15 minutes before rinsing off with warm water. Take special care to rinse and dry the area completely after using vinegar because although it’ll remove rust, the vinegar will continue corroding the metal if it’s left on.
- Lemon juice
Lemon juice works just as well as vinegar because it’s also extremely acidic. When you pair it with salt, it’s even more effective. An old-fashioned way of doing this is by cutting a lemon in half, sprinkling the exposed side with salt, and using it like a sponge to scrub at rusted areas. And just like you would with vinegar, make sure to rinse and dry the area completely soon after using lemon juice because it will continue to eat away at the metal and cause more damage.
Yes, a potato works to remove rust. How? Well, they have oxalic acid in them, and that eats away at rust. Simply cut open a potato, pour salt on its exposed surface, and use that side to scrub away the rust. Cut off more layers of the potato as you go on for the full effect of the oxalic acid. You can do this process as many times as you want. The pit should be rinsed and dried before using.
This is another strange one, but an easy way to get rid of rust is to use a cola drink, like Pepsi. The phosphoric acid dissolves rust with ease and is a great way to get rid of rust on small objects. For fire pits, let the soda sit on the rusted area for around 15 minutes before scrubbing it away. You can also soak a rag with it and set it against the area as well for a similar effect. Rinse and dry the pit completely before use.
6. Wire Brushing the Rust off
A wire brush is a good way to remove rust from a cast iron fire pit. This will remove all of the particles to stop the spread of rust. Make sure to wear eye protection and use a mask for any particles that may get in your eyes or lungs.
Keeping Your Pit Rust-Free
Now your pit is looking brand new. How do you keep it that way? Luckily it only takes three simple steps.
- Always Clean Out Your Pit
Every time you light a fire in your fire pit, clean out the ashes and any other debris when you’re done. Ash will absorb moisture from the air and will be left sitting against the metal long after the fire is out, so clear it out every time or rust will easily form. It is also recommended to clean out the pit every 2-3 uses with hot, soapy water so the soot and ash won’t become layered.
- Keep It Covered
When it’s cleaned out and not in use, store your fire pit inside and/or keep it covered tightly. This will greatly reduce the speed of the rusting process if moisture is kept as far away as possible from the metal.
- Apply Oil
A thin layer of vegetable oil is all you need to keep your cast iron looking new longer. Many people do this for their cast iron skillets, but it’s equally as effective for your fire pit. Simply pour a small amount of oil onto a rag and wipe the interior of the pit to create a very light layer. It will smoke a little when you first light a fire, but if there’s not too much oil it will quickly burn off.
Unfortunately, rust is inevitable. You cannot fully prevent it from occurring. It is possible, however, to stave it off. By performing the three maintenance steps above, you will keep your fire pit looking great for a long time. A fire pit can easily be ruined without proper maintenance and you’ll be stuck buying new ones over and over without it. So, make the routine a permanent one!
The bottom line: keep it clean, dry, and oiled for many more nights of cozy campfires!