Cutting cardboard?

MikeC

MikeC

Joined
Sep 16, 2005
Messages
1,364
Yesterday was the little ones birthday, spent all afternoon cutting up cardboard from gifts, we have a big extended family on both sides. Carboard varied in thickness from flimsy to fairly thick, my knife was not razor sharp when I started but sharp none the less.

When I finished I noticed it was noticeable duller, not dull per say just not nearly as sharp as when I started. This is the first time I ever cut up this much card board, as when I was finished I had nearly filled up a 64 gallon recyle bin. The recyle bin was empty when I started. Is this typical? Does cutting a lot of cardboard dull typically dull a blade down. Again this is the first time I cut this much card board so I don't know what to expect, please do not bash me for my ignorance, I am asking to learn, not to be belittled, or berated for my lack of knowledge. Is cardboard a material which dulls a blade quicker than other cutting media per say?

Thanks
 
Cardboard is one of the tuffest materials on a knife edge it will tear up even the best steels.
 
thank you, I assumed it was a blade duller, but I needed some advice from others on this site with more knowledge than myself.

Thanks again
 
I normally use a Stanley utility knife when cutting up large amounts of cardboard, and always keep a diamond steel handy....a few quick passes across the rod makes a big difference in cutting ability.
 
Cardboard is pretty abrasive, a lot of stuff gets into the mix during the manufacturing process. Quite a few people strop their knives on a piece of cardboard to finish the edge. It is faster if you load the cardboard with an abrasive compound, but it works without it. Anything that you can sharpen a knife on is bound to dull a knife when you are cutting it.
 
Yep. Depending on the cardboard, it can be very abrasive stuff. I once had to cut down a hideously thick cardboard box from a baby crib. The box was wicked thick, and you could feel the sandpaper-like surface with your fingers. I used the opportunity to test a number of knives for edge retention on that box. VG-10 dulled in one pass through the cardboard. S30V lasted for two passes. M2 lasted for many, many passes. I kick myself for not testing Dozier D2 on that box.
 
The other night I went on a cutting spree to clean up our downstairs basement. Tons of boxes had to be broken down and cut up so they could be hauled out. My knife was a Cold Steel Night Force with 440A stainless steel, plain edge. I cut up a bunch of stuff, some of it extremely heavy. Not only did the lock hold up without a problem, the knife blade was still sharp when I finished, which really surprised me given the steel. The cutting didn't mar the blade as much as I'd expected, either, but there was some wear to the black finish. But the knife's edge was in great shape. One box that a computer came in was so thick that I could barely cut through it, but once I started it cut easily all the way down.
 
I got a almost endless supply of recycled cardboard that I get from work, its the harshest stuff I have ever seen. Most steels won't even make a complete cut before it just starts ripping the cardboard, even dulled the crap out of S90V after a few cuts.
 
I just spent all day yesterday and the day before opening and resealing boxes doing quality inspection of lounge chairs and used my Izula to open about 600 large boxes. I had to touch the thing up after about every 50 boxes or so, but it didn't take much to freshen up the edge. Cardboard is a real edge-killer.
 
IIRC, cardboard has silica impregnated in it, as well as some clay. That would explain the abrasiveness. It is a very good testing media for knives, especially a really big piece that you can use multiple knives on.
 
At work I have to cut a boat load of cardboard on a daily basis, and I love it. It gives me a chance to use my knives much more then I would have otherwise been able to. Mostly I use SE edges like a full SE vg-10 or s30v knife.
 
sodak said:
IIRC, cardboard has silica impregnated in it, as well as some clay. That would explain the abrasiveness. It is a very good testing media for knives, especially a really big piece that you can use multiple knives on.
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Quick off-topic question.. what does IIRC mean? I can usually figure out internet abbreviations but I just can't come up with this one. :confused:
 
My wife said to me just yesterday, "Can you cut this box up and get rid of it?" It was a pretty heavy duty box. My response was "Where's the box cutter?" Her reply; "Don't you have a knife on your belt?". So I said; "Sure I do, but I just put a real nice edge on it. Yanno, you should use the right tool for the job. So where's the box cutter?" She just laughs and rolls her eyes at me as she fishes the box cutter out of the desk drawer. :D
 
odd as it sounds, all kinds of materials end up in the pulp used to make cardboard.

bits of metal being the most abrasive.

i actually enjoy using my knives to cut up cardboard, kind of a test of the edge an my sharpening abilities.
 
Leather is also very hard on steel. My knife edge holding test consists of carving a certain amount of a certain cardboard and reviewing the edge, then cutting a certain amount of leather and reviewing the edge, then carving on a specific piece of hardwood and reviewing the edge and comparing the results to a couple of known "standards". To date, D2 at HRC 62 has faired better than anything I have tried, though I certainly haven't tried everything.
 
MORIMOTOM said:
odd as it sounds, all kinds of materials end up in the pulp used to make cardboard.

bits of metal being the most abrasive.

i actually enjoy using my knives to cut up cardboard, kind of a test of the edge an my sharpening abilities.
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:thumbup: I love cutting up cardboard and do it any chance I get. It's a great test for edge retention, and I have sold knives that could not handle it. A good, premium steel knife should cut cardboard all day with no problems. The best part is that you can keep your knife sharp by stropping on the cardboard as you cut it up. At the end of the day, a few swipes on your preferred sharpening system or stone will have it ready for the next day, assuming you are using a quality steel and your edge is not too thin.
 
MikeC said:
When I finished I noticed it was noticeable duller, not dull per say just not nearly as sharp as when I started. This is the first time I ever cut up this much card board, as when I was finished I had nearly filled up a 64 gallon recyle bin. The recyle bin was empty when I started. Is this typical?
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Depends what steel, but I'd say yes, it's typical. My VG-10 Delica, starting razor sharp with no shine on the edge, is full of shine after I'm done cutting.... Say 6 boxes into tiny, tiny pieces. It's not necessary at all, but I like to see how much my knives can take before the go dull, and to what level of dullness.

And from the first cut to the last, it's very noticeable how much more difficult it becomes to cut.

MORIMOTOM said:
i actually enjoy using my knives to cut up cardboard, kind of a test of the edge an my sharpening abilities.
Click to expand...

Me too. I spend about an hour getting the perfect edge, then I cut cardboard for about 10 minutes which causes me to have to sharpen for an hour again... lol
 
J.Mattson said:
At work I have to cut a boat load of cardboard on a daily basis, and I love it. It gives me a chance to use my knives much more then I would have otherwise been able to. Mostly I use SE edges like a full SE vg-10 or s30v knife.
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In my experience, ease of using serrated edges depends on which side of the blade holds the serrations. If on the left (Spyderco), while cutting I find myself working my grip to keep the blade in a straight line. It wants to wander off to the right. After a while, the wrist gets tired. If on the right (Leatherman), the blade tracks easily. It has to do with mechanics of the activity, one force cancels out another, I guess:confused:. I'm right handed, though. Lefties probably have an opposite experience.

Overall, I prefer PE for the job, but serrated edges last longer before needing touchup.
 
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