Stainless steel is an alloy of iron and carbon with additional elements such as nickel, chromium and molybdenum. It’s corrosion resistant and has a lustrous appearance.
Stainless steel is usually classified according to a series naming convention, such as 18/8 (grade 304). It is often used in kitchen knives and in the automotive and aerospace industries.
1. Look for a patina
A patina is a protective coating that develops over time and with use on carbon steel. It prevents further oxidation and helps your knife last longer.
A patina may also appear on other metals, such as copper and brass. Typically, it forms a grey or black coloration.
It can also be red or orange in color on some metals.
The best way to check for a patina on your blade is to look at the stains it leaves behind. The darker the stains, the more patina it has.
You can easily make a patina on your knife by using mustard, but you can also use vinegar or other acidic substances like lemon juice and tomato sauce. This can be a fun way to experiment with forming a patina, but you should make sure to rinse it off and dry your blade properly. If you leave your blade in the vinegar or mustard too long, it can rust.
2. Look for rust
One of the best ways to tell if a knife is stainless steel is to look for rust. While there are other metals that rust, such as copper and aluminum, stainless steel is resistant to rust spots and discoloration because it doesn’t react with acid and saltwater like some other common household materials.
Rust stains are often caused by acids and salty food remnants on your cutlery, but they can also be a result of allowing them to get wet. A dishwasher isn’t the best option for keeping knives clean as it can corrode the blades from repeated washings and oxidise them.
If you have a rusty blade, there are a few simple methods to restore your knife to its former glory. While they may not be able to prevent rust stains from happening in the first place, these tips will help you remove rust and maintain your knife’s blades for years to come.
3. Look for scratches
Stainless steel isn’t entirely scratch-proof, so it can develop nicks and dings over time. Fortunately, you can get rid of scratches on stainless steel with a little elbow grease and the right products.
First, determine the condition of the blade. If it’s not in too bad a shape, you can get away with using a simple non-abrasive sanding compound to remove light scratches.
Next, you can use a handheld rotary tool to remove more serious scratches. The Avid Power Cordless Rotary Tool is an outstanding, multi-use device that’s a breeze to operate and can restore many scratched knives in one session.
However, if you’re dealing with deeper scratches that don’t come off easily with sandpaper, you’ll need to take extra steps. For example, you might need to use a buff and polish solution to help restore the shiny surface of the blade.
4. Look for dents
During the forging process, when hot steel is hit with a rounded hammer, it creates dents or depressions on the blade. These dents are sometimes left on the blade for a polished look, or they can be ground away to make the blade flat.
If you notice dents on your knife, this indicates that it is made from stainless steel. However, these dents may be too small to be visible from the surface of the blade.
Whether you are buying a new knife or looking to upgrade your current one, it is important to choose the right steel for your intended use. Many factors come into play when choosing a steel, including hardness and toughness, edge retention, corrosion resistance, ease of sharpening, and overall performance.