What does Ice Tempered Mean
The word ICE is so popular that a lot of carbon steel scissors proclaim to be ice tempered, which does not make any sense technically. Some people even think ICE is a brand name. The only important thing to remember is that ice tempering is only beneficial on stainless steel.In a simplified form, stainless steel is standard steel with chromium added to make the steel more rust resistant, thus stainless steel. The disadvantage of the high content of chromium in stainless steel is that the cutting edges blunt quicker leading to scissor sharpening. To overcome this, the steel is subjected to very low temperatures (frozen or “ice tempered”), to optimise the steel structure for hardness. This is how it works:
To make a steel hard, it has to be heat treated. With Stainless steel that means heating the steel above 2000 degrees Fahrenheit. At that temperature the structure of the material is at its optimum. To preserve this structure, the steel is cooled rapidly (quenched) and tempered at about 450 degrees Fahrenheit. Now you have a pretty good hardness and flexibility on you scissors except that the chromium in the steel will not permit a long lasting cutting edge. To make the cutting edge last longer, the steel is subjected to about 120 degrees below zero; in other words, Ice tempered. The scissors are not much harder, but the steel structure is at its optimum. It is virtually impossible to prove or disprove if Ice Tempering was done, without a steel analysis. The only proof is how many cuts one can get with a pair of scissors before they are blunt.
The Edge: Japanese style scissors have very sharp edges that taper to a point called a convex edge. These edges are very thin and sharp allowing the user to cut all techniques, including slide cuts and wisping.
Because the edges are so sharp, they would rub themselves dull on the hollow side of the edge. To keep this from happening, a hone line is ground in the hollow along the edge. The hone line is the thin flat line that you see on the hollow side of the edge that runs from the tip of the scissors to the back. This gives the scissor a smooth and quiet run. If we did not grind on a hone line, the scissor would run hard and loud. (The run is the feel and function of opening and closing the scissor). If a scissor sharpener does not sharpen and re-hone your scissor correctly, the scissor will never feel like when it was new. But if sharpened correctly, the scissor often feels and cuts better than when it was new!
A German scissor has flatter edges than a convex scissor. We call this a sword or bevel edge. Bevel edges are not as angled as a convex edge, thus requireing one or both edges to be serrated or corregated. A serreation are fine lines or teeth ground into the edge of one blade. The serration holds the hair, keeping it from being pushed forward.
Now we come to the performance difference differce between the Japenese(convex edge) and German (bevel edge) scissors. Because of its very sharp edges, the convex scissor cuts through hair smoothly and efficiently, with less force. The convex scissor is constructed for slide cutting or wisping. It runs smoothly, quietly, and very lightly. However it has the tendency to nick and blunt faster than a bevel edge scissor. It also has a tendency to push the hair more than a serrated bevel edge scissor.
The bevel edge scissor is very durable. It holds the hair very well and does not push it forward. It is the scissor of choice for blunt and layer cutting, dry cutting and for the cutting of synthetic and coarse hair. Its major drawbacks are that one cannot slide cut with it, because of the serration, and it runs louder and rougher than a convex scissor.