Question: Izula no good on cardboard?

Big_Red

Big_Red

Joined
Feb 23, 2009
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I understand this sounds like somewhat of a stupid question, but I am being serious...

I'm at my hunting property this weekend preparing kindling/stuff for the fire pit. As a base layer for the fire I cut a fairly big cardboard box into about eight sections.

Using my new Izula it got to be almost impossible to cut through this cardboard. I was using a substantial amount of force, both push cut and a sawing motion to get through the box. Towards the end I just tore the cardboard with my hands to finish the job. I was really crankin' down on that knife and getting nowhere.

Is it simply the thickness of this blade that is not the best for cutting cardboard? The edge bevel? Coating? All the above? The knife is sharp, I can still cut leg hair with the blade.

Don't get me wrong, I'm happy with the knife and certainly didn't buy it for the sole purpose of cutting cardboard :rolleyes:... just a bit surprised.
 
if you want it to cut cardboard you need to make your edge more aggresive....i use mine at work all day to cut open boxes of bulk meat....there're glued so i am cutting two layers of cardboard plus the glue.....but i had to go steaper with my grind...I damn near made it a scandi.....but it works and stays sharp for a while....I am digging it...
 
Believe it or not, cardboard (especially the recycled kind) is extremely hard on knives. It will dull even super steels quickly. I have even seen it cause chipping in some steels. The Izula will cut cardboard but like any other knife it will dull quickly. If I know that I will be working a lot of cardboard, I will generally bring a box knife or at least a strop so I can keep the edge refined.

I have also found that by simply angling the knife so that the point is trailing the edge as you pull the knife through will greatly improve cardboard cutting. It sounds silly but it works a lot better than trying to pull the knife through cardboard with the edge perpendicular to the cardboard.
 
Well it's probably not a dulling issue due to cardboard if it didn't work well right away. I can't claim to know the problem, but mine sees cardboard duty once or twice a week--tough boxes and weaker shipping boxes--and it'll slice through as a hot knife through butter for the first cuts. If it helps, the primary is 40* inclusive, the microbevel is 50* inclusive, and I strop.
 
matthewdanger said:
I have also found that by simply angling the knife so that the point is trailing the edge as you pull the knife through will greatly improve cardboard cutting. It sounds silly but it works a lot better than trying to pull the knife through cardboard with the edge perpendicular to the cardboard.
Click to expand...

Not silly at all... that's exactly what I found to work, but was still having trouble towards the end.

I may reprofile the edge to 30 degrees inclusive. Give me something to do. :D
 
I just last weak cut up the box my flat screen came in I used Izula RC-4 RC-3 RC-6
and RC-3 cut for the longest time then RC-6 then Izula RC-4 didn't last long at all.my
conclusion RC-3 best slicer but I already knew that.
 
I found my Izula cut's just about everything better after convexing the edge. The factory edge, while very sharp, is not acute enough to cut as well as it could. The convexing will give you a thinner edge and bring the coating back some. It makes a world of difference.
 
exidor said:
I just last weak cut up the box my flat screen came in I used Izula RC-4 RC-3 RC-6
and RC-3 cut for the longest time then RC-6 then Izula RC-4 didn't last long at all.my
conclusion RC-3 best slicer but I already knew that.
Click to expand...

Are you comparing factory edges or blade widths with regard to edge holding? If you mean (just) blade width, I really don't think the width will have much of a factor on how long knives with the same steel, heat treat, and edge angle will hold an edge because it's at the edge that matters, and they're all the same width there.
 
There is sand in brown cardbaord.
The silice is much harder than steel.
So it dulls the edge very quick.

In my country, "good and sharp scissors" are forbidden to cut paper for the same reason. You always keep some marked "dull scissors" only for that.

A boxcutter is usefull to ruin an edge on cardboard.
Use cardboard to strope the edge on your izula.
Works great !!!
 
thinning out the bevel will help you cut cardboard better however you will lose some edge strength... it's kinda give & take :)
 
cardboard is a pain to cut - no if's about it.
the technique I have found that works best for me is contra-intuitive.
instead of cutting straight into the cardboard, where the knife makes a "T" with the box, I cut with the knife beveled about 30-45 degrees from the box -- this way the thickness of the blade is not wedging between the cut, but rather the cardboard has somewhere to bend. (hard to visualize, but it works pretty well)
I also tend to cut with the tip trailing as opposed to leading)
 
matthewdanger said:
I have also found that by simply angling the knife so that the point is trailing the edge as you pull the knife through will greatly improve cardboard cutting. It sounds silly but it works a lot better than trying to pull the knife through cardboard with the edge perpendicular to the cardboard.
Click to expand...

I have found this works also. I cut some double thick stuff at work and some times just to test my edge.
 
Part of the equation is the thickness of the blade. A .22 thickness blade on a bigger knife for example still gives decent slicing geometry, but the same thickness on a small knife means it won't feel as good when slicing. I have a .22 knife with only 3 inch blade. It is definitely no slicer for some materials. It is very sharp, hair popping sharp with a polished convex edge. But with thicker cardboard it will not slice great. It tends to bind, and it is a bare steel, relatively polished as well. Coating can make it worse. I would be willing to bet that a thinner profile on the izula would do better for slicing, but then it is a trade off.

A 1/8th thick knife is going to slice better, but any lateral stress can cause problems. Every thing is a trade off with geometry.

(I don't know what the thickness of the standard izula is by the way)
 
can you shave hair in both directions? if not, you may have a burr on the blade, sometimes called a wire edge. it'd make it difficult to cut cardboard, but would be able to shave in one direction, and not the other. i use my izula all the time on cardboard, before and after i convexed it.
 
No, really.... Thinning the edge or taking care on any burr is not the point.

As a rule of thumb, you got a sharp knife, the best steel and the best geometry. You cut cardboard -> you gut a dull knife very quick. (The only exception was a CPM440V (S60V) balisong Fred Perrin made (56HRC) and which we "felt" like it was still sharp after... but S60V is some kind of enigma in edge behavior with its 2% carbon...)
But for "normal steel" especially at HRC57 (not "that" hard), there is no magic...
Cardboard will eat your Izula edge. Period.

BTW, I saw a video review of the RC3 by "Bluntruth4you"
http://www.youtube.com/watch?v=G66BmCuaf4U
He unfortunatly start by cutting lenght of brown cardboard.... and then you can notice how it's difficult (relatively speaking and compared to the Izula) for such an excellent knife to cut deep in wood. (His RC3 cuts less good than his Izula !!! And he knows how to sharp his knife, even to convex them...)
As far as I enjoy his video on the Izula cutting the 2x4, regarding the RC3 on the second part of his review, he should have started his demo with the wood and finish by the cardboard... Because it's obvious how much the RC3 is then dull when he started to cut the wood. And the RC3 is thinner, got more belly and should be a better wood cutter than the Izula.

Cutting cardboard on a regular basis should be avoid unless you REALLY enjoy resharpen your knives (any knives) a lot... Cardboard is REALLY abrasive !!!
Cutting cardboard is like dulling the edge with SAND PAPER !!!

Now you do what do you want with your tools.
But this is what my grandfather taught me 30 years ago and the old man, as an ebenist, woodworker, soldier and hunter, knew how to take care of his knives. :-)
 
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Once in a while I can't avoid cutting cardboard - and the Izula does a very good job of it, but I have to strop it every few cuts - I just use the cardboard to strop and go on.
 
For what it's worth, I have used scandi-ground knives for cutting cardboard and it goes through it like a lightsaber.
 
luckykitty said:
Once in a while I can't avoid cutting cardboard - and the Izula does a very good job of it, but I have to strop it every few cuts - I just use the cardboard to strop and go on.
Click to expand...


Every now and then I cut cardboard also. This material has dull my AFCK D2 into a butter knife once.:grumpy:
Cardboard is not knife friendly.
(Welcome in the +1000 posts BTW)
 
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