Nearly everyone that owns a knife has heard that cutting paper or cardboard will supposedly ruin and dull their knife blade. But what about the people that test a blade’s sharpness by cutting paper? I Was confused by this as well, so I did some research.
Depending on the grade and type of paper, cutting paper with a knife will eventually dull and even harm the knife blade. While the organic fibers in most paper won’t necessarily harm or significantly dull the knife blade, the many fillers and added materials in paper have the potential to.
This might be kind of counter-intuitive for many because paper seems WAY softer than a knife blade, so why would it be so bad for it? Let me break it down for you.
Why Does Cutting Paper With a Knife Dull or Harm the Blade?
Basically, anything you cut with a knife will dull the blade in some way or another. The motion of cutting through material and creating friction on a knife blade will dull the knife just a tiny bit every time you slice or make contact with the material you are cutting.
The organic material that is in paper will dull your knife blade, just like everything else that you cut with your knife blade. However, the thing that makes cutting paper potentially more harmful to your knife and its blade than other materials, is the variety of synthetic and other materials added to the paper.
While normally you are able to see what type of material you are cutting with your knife, paper has a tricky way of making you think that you are cutting something really soft and harmless but is really hiding some hard and harmful substances that you are unable to see.
While most paper is mostly made up of wood and other organic pulp materials, there are filler substances added to many types of paper today. These filler materials include clay, chalk, rosin, and other synthetic and organic materials.
The filler materials that are added to many types of paper are often very rough and will slowly chip and grind away at your knife blade.
And so, while the organic material that paper is primarily made of will slowly and almost unnoticeably dull your blade, the main threat is the added fillers, synthetic materials, and other things added to the paper.
While it is not the best thing to do for your knife blade, cutting a little paper now and again most likely isn’t going to cause any harm. As long as the paper that you are occasionally cutting isn’t super thick or have a TON of added fillers and synthetic substances, it should be fine.
Below I will do into a little more depth into the common types of paper and how cutting each might affect a knife blade.
Types of Paper and the Impact Each Will Have on a Knife Blade
There are many different types of paper that, when sliced or cut with a knife blade, will have different effects on the blade of the knife. It really all comes down to how many abrasive synthetic materials and fillers are added to the paper and some other factors like the weight and thickness of the paper.
There are three common types of paper that you are most likely to run into on a regular basis:
- Printer paper
- Coated paper
I’ll go into a little more detail regarding the common effects that each type of paper has on a knife blade because of what the paper is made of and some other factors.
Generally, printer paper is made of organic pulp, just like most other paper, but also contains a large amount of filler and added materials.
This is particularly important to remember because the added materials and fillers are often very abrasive and will wear down and dull your knife blade faster than a paper with less added materials.
However, printer paper is the most common paper that you will most likely find and it is one of the better options to cut with a knife. While cutting paper with a knife isn’t necessarily good for the blade in the first place, cutting printer paper is probably going to be your best option because the alternative common paper types are even worse for your knife blade.
The reason that coated paper is glossy and seems to have a sort of coat on it is usually because of the large amount of clay and fillers present in the paper.
This makes coated paper even worse than printer paper to cut with a knife because the huge amount of fillers will just grind away at your knife blade.
Some coated paper does not have such a large amount of clay and fillers in it and is simply covered with a fine protective coat to make it glossy and smooth. This coating on paper will still do some harm to a knife blade but is better than a bunch of filler and added materials that are in most types of coated paper.
Because it is really intended for single-use purposes and only has enough strength to hold up when a page is flipped, newspaper is very thin and often made of recycled materials.
The thinness of newspaper makes it not very suitable to use to test a knife’s sharpness and you won’t find yourself cutting it with a knife often. If you do try to cut it with a knife, it most likely will just rip because of how thin it is.
Another downside of newspaper in regards to being able to cut it with a knife is the fact that it is made of recycled materials. This means it will sometimes contain small particles of plastic, metal, and other synthetic and organic materials. These bits of recycled material will absolutely destroy your blade if you cut newspaper too often.
Other Factors in How Different Types of Paper will Impact a Knife Blade
While the type of paper that you are cutting with a knife makes a huge impact on how it will dull and effect your blade, there are a few other factors to consider.
While above I talked about the makeup of each type of paper and the potential harm each can do to a knife blade, the below factors apply to almost any type of paper.
The thickness of the paper that you are cutting will make a huge impact on how it affects your knife blade.
The thicker the paper is, the more likely it is to contain larger particles of filler and other harmful materials as well as just being more material for the knife to have to cut through. Thinner paper will usually cause less harm to a knife blade and will dull it slower than thicker paper.
Heavy paper is often very dense, contains lots of added materials and fillers, and is often quite thick. All of these common attributes of heavy paper are all not very good for a knife blade to cut through.
Basically, the heavier the paper, the more it will dull and potentially harm your knife blade.
Amount of Added Materials
Added materials and fillers in paper is one of the main things that actually harm a knife blade. Without fillers and added materials in paper, the pulp and organic substances that paper is primarily made of would cause very little harm to a knife blade.
While paper without fillers and added substances would still slowly dull a knife just like cutting anything would, the added materials and fillers make cutting paper sometimes very harmful to a knife blade.
The fewer fillers and added substances in paper, the less harmful to a knife it will be when you cut it.
Does Cutting Cardboard Dull or Hurt a Knife Blade?
Many people don’t think of cardboard as a paper product, however, it actually is. Unfortunately, just like paper, cardboard is also pretty bad for a knife blade to cut.
Cardboard is typically pretty thick, heavy, and made of recycled materials. All of these attributes, as we have discussed earlier, are really bad for a material that you are cutting with a knife blade to have.
The thickness of cardboard makes it just have a lot of substance to cut through and will dull the knife quicker than a thinner material would. While it actually relates to how dense and hard to cut through it is, the weight of cardboard makes it also not very suitable to cut with a knife.
Lastly, the fact that cardboard is often made of recycled materials is a major red flag when it comes to cutting it with a knife blade. The recycled material has the potential to be pretty big and can really cause some damage to a knife blade by scraping and dulling it.
Overall, paper and cardboard aren’t that great of materials to cut with a knife blade, but doing so every once and a while won’t completely ruin your blade. Just be aware of what the material that you are cutting is composed of and know that you will have to sharpen your knife at some point anyway.