Finishes and Coatings

When looking for your new knife, it can be easy to overlook the finish or coating that has been used. The finish might seem like a purely aesthetic choice, choosing your finish based off of what it looks like. While this does play a role, each finish or coating offers different advantages and it would serve you well to know what those advantages are. Certain finishes can add strength or durability. Some help the knife resist corrosion. Some truly are just for aesthetic. There are eight different popular finishes and coatings. They include: bead blasted, brushed, coated, head treated, mirror polish, satin, stonewashed, and TiNi. These eights are the ones that we are going to go over today.

 

Bead Blasted Finish:

Bead blasting doesn’t necessarily always use beads. The finishing process is done by blasting abrasive materials, such as glass or ceramic beads or sand, against the knife’s metal at a high pressure.

If you use a sandblasting technique, it does a fantastic job of smoothing, shaping, and cleaning harder surfaces. It is a very similar process to using sandpaper on your knife, except that the overall finish is more even. The process of sandblasting also removes rust and imperfections in the steel. This is a great process to use before you apply a different finish on top of it.

If you are using the bead blasting technique, it creates a clean, bright, and uniform texture. This process can remove paint, rust, and corrosion. The smaller the beads that are used, the smoother your surface is going to be.

By doing this, it results in a matte gray finish that is even across all the metal. Some advantages to having a bead blasted finish is that light reflection properties are reduced because the finish is matte. This means that if you are trying to conceal yourself while using your knife, you don’t have to worry about the metal giving away your position. However, a disadvantage to having this type of finish is that while the high pressure blasting leaves micro abrasions in the metal. This means that your blade will be more likely to rust or corrode. Even if your blade steel is a stainless steel, if you happen to leave it in a wet area, you can expect rusting.

 

Brushed Finish:

This finish is created by using an abrasive wheel. This wheel produces a finish that is similar to the satin finish. But, this finish is cheaper than the costly satin finish. This is one finish that you can combine with another finish, such as a brushed finish and a hand satin finish. The abrasive wheel creates a pattern of fine parallel lines, it mutes the luster of the finish. It still has some reflective properties, but it is not undesirable. Unfortunately, this finish reduces the steel’s corrosion resistant properties, because the abrasive wheel does create micro abrasions that are more prone to rusting.

 

Coated Finish:

A coated finish is most commonly found in black, gray, or neutral colors. The coatings will reduce light reflection and glare. The coatings also help to reduce corrosion and wear. A drawback to having a coating finish is that they can and will scratch off after heavy use and over time. With these coated finishes, you are aiming to get the hardest coating possible because the harder the coating, the harder it will be to scratch off. But, the harder the coating, the more expensive it will be. The high quality finishes are bonded electrically, chemically, or thermally. This is different than the paint-on coatings, which just have to dry onto the blade. Before most coated finishes, the blade will be bead blasted, because it does create the micro abrasions. This helps the finish stick, because it can actually get into the blade. These coated finishes prolong the life of your knife because they help resist corrosion and rust. The higher quality coatings are more expensive, but they are also much easier to maintain. Some very popular coatings are:

Black Oxide is also called blackening. This is a coating that slightly boosts the corrosion resistant properties on the blade. It also adds a pleasing black color to the blade. This is sometimes used so that your blade will match the handle.

Black Paint is a powder coating. This is actually the lowest quality of coated finish. This helps reduce reflective properties well but it will chip and scratch very easily.

Powder Coating helps with corrosion protection, it looks great, and it reduces the glare on your knife. However, it is one of the least effective methods of coating your blade.

Teflon Coating helps with the blade’s corrosion resistant properties, it looks awesome, it reduces the glare on your blade, and it makes cleaning your blade very easy.

However, any knife that has a coating will be thicker and drag more than a knife that has not been coated.

 

Heat Treated Finish:

Out of the eight that we are going over today, this is definitely the black sheep. It actually isn’t a finish or coating that is put on the knife. This is a process that hardens the steel. The steel is heated and cooled to actually change the metal’s physical properties. Even though it does become harder, the steel retains most of its flexibility. But a heat treated knife can be very brittle as well. By doing this treatment, the blade can hold an edge better than it could before and the overall blade is more durable. The process is as follows: the steel is heated up to 1922-1994 degrees Fahrenheit. Then, the steel is quickly cooled, or quenched. The higher the temperature is while going through the process, the softer your material will be, but with higher toughness. The lower the temperature of the process is, the harder and more brittle your material will be afterwards.

As a guideline, camping and survival knives are usually heated to about 662 Fahrenheit so that it can take a beating but not break. These are the knives that are going to be going through the hardest tasks. But, if the user is looking for a knife that is going to stay sharp for very long periods of time, the steel will be heated to around 347 Fahrenheit.

 

Mirror Polish Finish:

This finish is actually done by hand. The metal is polished until it is highly reflective. Because it is all done by hand, this finish greatly increases the cost of knives with this finish. If you desire this look but don’t want the cost, you can have a tumbled finish that mimics the mirror polished. Of course, it isn’t going to be as reflective, or as high-quality, but it will give you the look that you are going after. This finish looks very pleasing. This is a very unique finish that you don’t commonly see and it is mostly a show finish. You will usually find this knife on high-end, custom, handmade, or collector’s knives. This finish also increases the corrosion resistant properties, because the metal is extremely smooth. Plus, because the finish is so smooth, whatever you are cutting is less likely to get stuck to the blade, making cleaning a breeze. Another bonus about this finish is that you can use it as a signaling mirror. However, because it is not usually on survival knives because of upkeep, it will probably be unlikely that you have a mirror polished finished blade with you at that time. Unfortunately, this finish requires lots of maintenance to upkeep its look. This is not a finish you are going to want on a tactical blade because the reflection of light will give your positon away. This finish is also very easily scratched, so you aren’t going to be able to complete most tasks with a mirror polished blade.

 

Satin Finish:

The satin finish is semi-shiny finish. It lies right in between the matte of a bead blasted finish and a mirror polish finish. This is probably the most popular and typical finish on knives. You can see the buffing lines with two directional finishes that help show of the bevels of your blade. This is because the blade is sanded in one direction with increasing degrees of a fine abrasive such as sandpaper. The finer the abrasive used and the more even the line; the cleaner the satin finish will look. This finish is done by hand and requires high skill levels. This finish also reduces its reflective properties, making it less likely to glare. This finish has pretty average corrosion resistant properties, but it is not as resistant as a mirror finished knife.  A satin finish is not always used solely for the blade of the knife; it can also be used on the handle or the fittings of your knife. Either of these will enrich your knife’s look. Because this finish is done by hand, it is a lengthy process. Because it is a lengthy process, knives with this finish are going to be more expensive.

 

Stonewashed Finish:

This finish is achieved by tumbling the blade in an abrasive material. This is usually done by rolling the knife around with pebbles and then it is smoothed out. This finish makes the steel less reflective than a brushed or satin finish. A huge advantage to having this finish on your knife is that it easily hides scratches, making your knife very easy to maintain after it undergoes this process. This finish also hides finger prints better than the other finishes, so you do not have to continually polish your knife. Depending on which manufacturer you get your knife from, a stonewash finish can actually look like a satin finish from afar. There are many different varieties of a stonewash finish because there are many different materials that can be used, there are different tumbling motions, and knives can start off with different finishes before they are stonewashed. One of the popular stonewashed finish is an acid stonewash, sometimes known as a black stonewash. This is when there is an acid treatment that darkens the blade before it is actually stonewashed. Because the acid oxidizes, the blade has increased rust resistance because the acid places a barrier between the steel and whatever you are throwing at it. Like the satin finish, the stonewashed finish can be done on the knife handle.

 

TiNi Finish:

This is actually also a coated knife, but it is a unique coating for your blade, so it will get its own category in this article. The TiNi finish is short for Titanium Nitride. This is a crazy hard ceramic material. This has been considered to be the best coating for your blade’s steel. This is usually used on black finishes to increase the durability of it. This coating actually helps the blade hold its edge. A huge advantage of the TiNi finish is that it is by far the most resistant to scratches and peeling. This finish is applied to the steel by a process of plasma deposition. This type of finish is going to be commonly found on tactical, military, or survival knives because it improves the blade’s surface properties.

 

Conclusion:

There are many different advantages and disadvantages to each of these knife finishes and coatings. Many knife enthusiasts prefer to have a finish over a coating because coatings can cause drag and reduce some of the properties on your blade. However, there are quality coatings out there, such as the TiNi coating. Even though many prefer finishes, there are disadvantages and advantages to each finish. Some are going to make your blade rust easier than before, even if it is made out of a stainless steel. Overall finishes and coatings greatly enhance your blade and will work to prolong the life of your knife. Each coating and finish will provide a very different look for your knife and part of the choosing process is really just figuring out which look you prefer. Don’t overlook the finish or coating on your knife because these characteristics can drastically change the blade.