If knives have one enemy besides politicians trying to criminalize their use, it is rust. When rust appears on a blade, bolster, lock or any other metal part of a knife, it will start to corrode the metal, eventually leading to pitting and a breakdown in the metal. It can leave the user of the knife vulnerable to tetanus if it comes in contact with blood through an accidental cut. The impact on rust can lead to the destruction and devaluation of the knife and poses a health risk.
Thankfully AutoKnives has you covered and can help you address the issue of rust before it happens and even after the fact.
The Science Behind Rust Formation
Scientifically, rust is an iron oxide. It occurs when the iron in the steel contacts water through immersion, water in the atmosphere (a humid environment) or in the cases of neck knives, it makes contact with the wearer’s skin, and it attacks carbon steels and tool steels maliciously.
The use of stainless steel in knife components helps to alleviate this problem, because stainless steels have a high enough percentage of chromium which helps offers a layer of protection and prevents rust and corrosion from reaching the underlying layers of steel. However, it is not a complete form of protection as exposure to certain chemicals, acids, heat, moisture and the like for extended periods of time can cause the stainless steel to corrode.
Most kitchen knives and pocketknives are made of stainless steel because these types of blades are the most susceptible candidates for rust based on their intended uses. Still, because we are talking about stainless, it doesn’t make them completely rust proof, just better than the carbon and tool steel counterparts for resisting it.
However, there are specific methods of rust removal that can help repair or restore your knife to its former glory depending on the steel type in question.
If you see rust forming on the edge, or surface of the blade that may come inContact with your skin or anything else wet, acidic, etc. There are ways to fix this issue.
Common Household Methods for Rust Removal
Thankfully, you don’t necessarily need to invest in special equipment or hazardous chemicals in order to remove rust from your knife. Remember the adage: “An ounce of prevention is worth a pound of cure”. Clean your knives after use with hot water and dish soap. Completely dry them using a towel followed by a silicone reel cloth if you have one or even blowing them dry by means of an air compressor, particularly with folding knives to prevent the liners, lock or other internal parts from rusting.Some knife users will follow up with a light coating of a non-toxic lubricant such as CLP, mineral oil or even olive oil and wiping them dry again.
If your knives are showing signs of corrosion you may be able to fix it with these common materials found throughout your kitchen.
Baking Soda Method
Baking soda is a typical home remedy for removing rust from metal with light stains. You will need to combine baking soda with enough water to form a paste. Think of the consistency of the paste you used in kindergarten. You will want to coat the affected area completely with this solution using your fingers or a toothbrush and let it set for an hour. Hit it with a fine grade of steel wool or a wire brush and scrub it until the rust is gone. A severe case may require a hot water rinse and a reapplication until it is gone. When it is eliminated make sure to dry it completely.
Lemon Juice Method
Lemon or lime juice from a fresh piece of fruit as opposed to the bottled type combined with a heavy grain of Kosher salt can clean up a piece of steel with bad surface rust that may be starting to pit. Coat the steel with the salt and squeeze the juice on it Let it sit for 2 hours and scrub it with the rind of the fruit. If it is still present, work on it with the fine steel wool, or wire brush. When the rust is gone, wash it and dry it properly.
White Vinegar Method (acetic acid)
Another way to remove rust from a knife blade or handle is to immerse it in white vinegar for a few hours. This works well on artifact knives recovered from being buried or left out in the open for long periods of time. Depending on the corrosion level, this can take over 24 hours. You will need to have steel wool or a wire cleaning brush available. Once it is free of the rust, wash with soap and water, dry and lubricate.
Bar Keepers Friend and Warm Water
Bar Keeper's Friend is an amazing rust remover for cleaning rust or acidic stains from your knives. Start by washing the rusted area with hot water and sprinkle the Bar Keepers Friend onto a wet cloth or sponge so you can scrub the corrosion. Do not leave the Bar Keeper's Friend on the metal for more than a minute. Rinse in hot water and repeat the treatment if necessary. Ensure you dry it thoroughly to not let the Bar Keeper's Friend stay on the metal any longer than 60 seconds.
Any of these methods can restore a knife to pristine condition safely and naturally without the risk of using something toxic. Remember, even a stainless-steel knife can rust. Inspect your kitchen knives, often, as you can unknowingly hurt yourself or others by using a rusted knife for food preparation.
Advanced Methods for Rust Removal
The following methods can be used on carbon steel or tool steel knives and are not recommended for use on stainless steel. These products may have the potential to damage chromium present in the knife blade.
Rust Eraser
Rust Eraser is a Japanese product that resembles a whetstone. It was designed for use on Japanese knife blades which are used in the kitchen as they are most often made from carbon steels to remain sharp and tough for long periods of time. You simply use the stone against the sides of the blade to remove spots after soaking it in cold water for a few minutes. Go lightly as the stone is abrasive and can wear down the exterior surfaces of the knife blade.
Use these following solutions in a well-ventilated area and use protective gear as they can cause damage, particularly if you are allergic,
Oxalic Acid
Products made from oxalic acid can be used to remove rust in sever cases by mixing with water and soaking the rusty knife for about a half hour. You will need to have your steel wool or a wire cleaning brush available to scrub it and you should wear rubber gloves as well. Once it is free of the rust, wash with soap and water, dry and lubricate.
Phosphoric acid
This acid can be used to give your knife an acid bath with a solution of 30-50% acid in water depending on the severity. After a soak, don your rubber gloves and get busy with the steel wool or wire cleaning brush. Once it is free of the rust, wash with soap and water, dry and lubricate.
Citric acid solution
For a strong acid bath that requires little to no scrubbing, there is always citric acid. It may cause skin irritations so use rubber gloves and it would not be a bad idea to don a respirator or at least a paper mask. Simply soak the rusty blade for as little as 20 minutes to as long as a few hours. Wipe it down, rinse it off and dry thoroughly.
The acids listed above go after the free ions found in the iron, which bond to the oxygen molecules and create rust on the knife. Stainless steels have other elements present, and these caustic methods listed above can permanently damage the various protective layers in your favorite knife’s steel. We recommend coating blades with a light dose of mineral oil after any of these cleaning methods,
If you have a favorite knife that got hit by the rust monster or inherit a potentially valuable one that has seen better days and you are not sure of your level of ability; contact AutoKnives for professional help.
Keeping Your Knives Rust-Free
Preventing and removing rust is essential in order to prolong the life of your knife and promoting safety in food preparation. Regular inspection of your every day carry pocket knife and knives you may have stored in the house is essential if you live in a humid area.
Maintain your knives properly by cleaning with dish soap, drying thoroughly, lubricating and storing correctly in a safe or cabinet with a desiccant pack or a dehydrating element to eliminate excess humidity.
AutoKnives offers a wide range of rust-resistant knives including pieces with stainless steel blades, and we are ready to answer any further knife-related queries.