Stuff you wouldn't think would dull a blade

T. Erdelyi said:
Obviously this must be your handiwork...

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I don't care who you are, that is funny! Good one Erdelyi.

Blessings,

Omar
 
Zip ties dulled my PM2 M390 in no time. I had no idea they were that hard on an edge!
 
I have a good quality serrated bread knife sharpen it on the paper wheels and it cuts like a laser for about two weeks then it needs a touch up, only use it on a cutting board.

Richard
 
After reading all the replies, I wonder how much of the dulling has to do with the type of edge that is on the knife. I think some of the edges are so thin that they may be extremely sharp like a razor blade (very low sharpening angle with very little metal left on the cutting edge) but can not withstand heavier cutting chores. Some of my heavy users have a steeper angles for heavier chores that seem to withstand harder use, however the trade off is they are not hair popping sharp. I save my thin edges for food prep and light cutting chores. Disposable utility knives are great for the insulation, fiberglass, rugs etc, when dull just replace.
 
The worst material I have ever tried to cut is nonwoven polypropylene fabric - this material is used in the construction industry as a filter fabric typically specified in Division 2/Sitework. It looks like a very thick/heavy plastic felt. We did a landfill project with a 6 oz. fabric specified between the sand filter and the protective dirt cover. Absolutely cannot cut with a non serrated knife. The guys would get about 2-4' out of a utility knife blade before it quit. I had a Gerber multitool with a serrated blade on it that I gave to them while I went back to town and picked up a bunch of cheapo bread knives. Luckily, we did not have to make too many cuts cause it was a booger. Needless to say, the guys lost the Gerber - its now buried under about 60' of trash.
 
Groove said:
Today I'm splitting and sizing soft foam pipe insulation (much like neoprene) for a project at work. First up was my Kershaw Skyline FB, it sliced like a laser beam for about five or six (6ft long) slices, then started to grab and tear the foam. I grabbed my Spyderco Tenacious out of my bag and continued with about the same amount of slicing before the edge was grabbing and hard to work with. Has anyone else here worked with this type of foam insulation?

This got me to wondering. What other seemingly innocent materials will kill an edge so quickly?





Eric
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A friend of mine is real big into LARP (live-action role playing) and he makes all of his weapons with camp pad. He cuts the camp pad with knives, and every weapon or two his knives go from shaving sharp to incapable of cutting... All he cuts in foam camp pad. That stuff is hell on an edge. Another nasty material is whatever soda can boxes are made of. That kind of cardboard/manila envelope offspring. Dulls blades (be it box cutters or knives) like nobody's business.
 
Cutting tree roots dulls my knives extra fast. But thats probably because they are still in the ground as im cutting them and I sometimes hit dirt or sand by accident.

Also plastic soda bottles can be hard on an edge if you cut enough of them.
 
Cutting nylon rope with portions of it wrapped in electric tape,was eating my edges or more accurately, the impregnated dirt mixed with the adhesive on the tape/rope was doing the deed, didn't figure it out till later.
 
Carpet has gotten me many times. Cutting old carpet especially. Its impregnated with sand and grit. Dulls a knife like it was made to do just that.
 
Bamboo is quick to dull if you try to cut straight through it. We have wild bamboo growing out where I live and it's tough to cut
 
On my rush out the door saw an annoying weed in my lawn, to lazy to go back in the garage for tools plus to lawn was moist, pryded it out with my adamas and bam, went from razor sharp to absolutely dull.
 
Body shop guys don't cut sandpaper, they fold it both ways and it rips very easily. For cutting stuff like that a cheap pair of EMT shears does a much better job - I have more than one pair and have cut horrible stuff with them for years, they keep asking for more.

I've found that the surface you are cutting ON messes up the edge worse than the object being cut - Formica is horrible on blades. It's made of compressed paper with a sem ceramic color coat on it. As you cut thru, the edge drops onto that and you are now pressing it into the surface of the counter. Take a look while slicing a tomato, the knife goes dull dragging on the countertop. Wooden cutting boards are much preferred, and technique alone can make a difference.

Case in point, cutting rubber hose with a knife, I was working on the particle board shelving with metal edges used to store the boxes. As long as I didn't drag the edge on the board, the knife stayed sharp. The EMT shears, tho, are twice as fast and cut square ends more easily. They can handle 3/4 heater hose, and I don't waste time away from the counter messing with it.

Antifreeze boxes are tough - it's no joke, the pulp contains abrasives and there's really no reason or way to filter them out. Cut down a dozen and by the end you will be working the entire edge looking for the sharpest part. What does help is not trying to have a super thin fragile edge at a thin angle. Utility cutting isn't brain surgery, don't use a scalpel, use something with a toothy medium edge. What you discover over time is that alloy does make a difference at that point - the more expensive ones that are harder to work are also harder to dull. The grain and abrasion resistance pay off then.

That's why we get by with cheaper blades in EDC knives - we don't spend all day cruising the Northwoods blazing trails and wearing out the edge. Those that do move to disposable, or pay the consequence - an afternoon's sharpening to get their D2 or S30V back to usefulness. That's the downside of the high dollar blade, it takes forever to get the edge back.
 
Ernie1980 said:
Bamboo is quick to dull if you try to cut straight through it. We have wild bamboo growing out where I live and it's tough to cut
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It grows wild all over the place here too. oh yea, its rough stuff on a blade if you don't know what you're doing.
 
Was chopping an old skateboard of mine and soon realized that the grip tape had demolished the my edge. I didnt even think about the fact that griptape, which I have years of experiences with destroying shoes and rug burnin me, is pretty similar to sandpaper. Dulled all my choppers that day. It only took a couple minutes each to repair them but needless to say it was a bad idea.
 
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