Worst things to cut thread

[SF Native]

Ok, I’m not talking about cutting your own finger, stabbing the family dog or anything like that.

For a while I thought that carpet was the worst thing to wear down a blade. The last few weeks as I’m working on my house I discovered fiberglass batt insulation. My poor endura is already the red headed stepchild and gets all the hard tasks. Not only does the paper backing has black goop to gum up the blade but the glass fibers dull the blade pretty severely in maybe an hour or half hour of use. I’m resharpened frequently. I guess it’s not surprising as it is glass fiber.

What about you? What wears your blade down?

[Evil D]

Carpet, drywall, some corrugated is loaded with clay and crap and heavy starch glue that will wreck an edge, insulation, nylon/nylon rope..

[MattM68]

I’ve found the worst things to cut are the things your friends need to borrow your knife for. That’s why I don’t loan out my knives!

I’ve never really had a problem with insulation dulling my knives. My VG-10 Delica handled it pretty well! Carpet on the other hand will destroy an edge pretty quick.

[tvenuto]

Gym mats, otherwise known as horse stall mats. 3/4 inches of rubber that closes back on the blade. Best thing to do is set a 2x4 under the portion you want to cut so the cut opens and the blade doesn't drag. Highly recommend a replaceable bladed knife that doesn't retract.

[Eli Chaps]

I work in metal casting and we have various high-temp "fiber glass" type insulation materials and they absolutely wreck blades.

[wrdwrght]

Any stuff that grips/contaminates the edge. Wrapping and taping cellophane each require assiduous cutting to avoid getting caught or gunked up.

[vivi]

skateboard grip tape. Extra thick, low grit sandpaper with strong adhesive on the back.

Used to use my Tasman Salt SE every few weeks for the job. Laying the flat side against my skateboard, the chisel grind was super easy to control.

[Evil D]

Plastic film is surprisingly hard on edges. I worked in polyethylene extrusion for a while, I wasn't quite as into knives as I am now so I never found out what kind of steel they used in their slitter blades but some films really did a number on them. It's kinda hard to say though because we sometimes ran millions of feet during an order so if you look at it that way they seem to hold an edge very well. The issue was that once they dropped down to a certain level of sharpness they would stop making clean cuts, even though they still had plenty of working edge. We could also adjust the blades to a fresh spot on the edge so you could get a lot of use out of one blade and they were double edged like a straight razor.

[TomAiello]

Roofing shingles. The heavy tar ones, with pebbles in them.

[Larry_Mott]

Fiberglass muffler baffle wrap for motorcycles. Child safe knife in under an hour..

[Joey]

Roofing shingles. The heavy tar ones, with pebbles in them.

I’m sure you could dull a knife quicker by cutting dirt (sticking the blade in the ground), but this gets my vote as far as task cutting goes. Those “pebbles” probably won’t cut by any means. I imagine they’d wreck any blade after a good hour or two of cutting.

[The Meat man]

Roofing shingles. The heavy tar ones, with pebbles in them.

You didn't actually cut through into the gravel did you?

I remember you saying that you used your Maxamet Manix for this job once. Can't remember what damage, if any, happened to the edge.

At any rate I must agree that this qualifies for one of the worst things to cut. I used to do construction, and on big roofing jobs we wore away a lot of utility knife blades cutting through shingles. I never even considered using a pocket knife.

[crazywednesday]

Roofing shingles. The heavy tar ones, with pebbles in them.

+1

[Archimedes]

Zip ties.

Plastic clam shells. Hate these things.

[curlyhairedboy]

Anything containing fiberglass.

[Doc Dan]

Porcupines.

[TomAiello]

Roofing shingles. The heavy tar ones, with pebbles in them.

You didn't actually cut through into the gravel did you?

I remember you saying that you used your Maxamet Manix for this job once. Can't remember what damage, if any, happened to the edge.

I didn't actually pay attention to the gravel. I'm sure I hit some of it.

I actually repeated this several times on purpose, to look for blade damage. Manix 2 LW (Maxamet), Manix 2 s110v and PM2 M390. The Maxamet was impressive. Very little damage and stayed sharp the best. The M390 showed almost no damages actually, but definitely lost it's edge. The s110v chipped.

I originally did this because I was helping my daughter with a science fair project (she was measuring the effect on wi-fi reception of various materials placed between the transmitter and receiver), so it wasn't an "all day cutting" kind of thing. I just used the knife in my pocket (the PM2 in M390). I later tried replicating the cuts with the other two knives.

[termite]

I cringed a little thinking of using a pocket knife to cut shingles. I can't imagine how many of those Stanley hook blades I've gone through, but if they weren't soft from being hot I used a pair of 10" tin snips (the old-school type). They didn't have to be sharp and were faster on the two-layered Tamko Heritage type with a nice neat cut. Always had some WD40 around to spray 'em if they got gummed up. That was a long time ago...it'd kill me to shingle now.

[Stuart Ackerman]

Kevlar cloth or random mat.
Scissors work better.

Spyder-Scissors anyone? :)

[ZeroRange]

The worst material I've cut so far is sheetrock and the mud they use use for taping. I dulled my S30v PM2 very quickly but I have a Contego in M4 that held up a little better.