Glue
Selection of adhesives to be used with ISZ KNIVES
The most time-consuming part in selecting materials was the adhesive.
We started by comparing the catalog specifications of each manufacturer, such as the types of adhesives that correspond to the objects to be glued, and the innumerable physical and chemical properties required for them.
Adhesives, like steel, have contradictory physical effects, and for knife applications, emphasis is placed on tensile shear bond strength, peel bond strength, and elongation.
glue for knives
There are many types of adhesives, and since it is not possible to list them all here, I will list the representative types.
・Urethane adhesive
Urethane-based adhesives are not as strong as acrylic or epoxy, but they have a very high elongation rate. In addition, many of them have good weather resistance and can be used for full-tang knives, but the drawback is that they have a low durability and hydrolysis occurs due to deterioration over time. Not suitable for knives.
・Acrylic adhesive
This type of adhesive has outstanding adhesive strength comparable to epoxy, and is characterized by very good workability. However, although acrylic has a longer lifespan than urethane, it is still 10 to 15 years. They also have relatively low heat resistance.
・Epoxy adhesive
The most suitable adhesive for knives is epoxy, which has many achievements. Many epoxies have high strength and high weather resistance, so there is no need to worry about their durability.
However, knives with weak handle materials require elongation. The elongation rate is a factor to follow the material that bends, but the type of epoxy with high elongation characteristics has low adhesive strength.
Especially with the latest model, it is a problem, but unless you assume a special use, I think that there is no problem with a commercially available strong one.
Adhesive used with ISZ KNIVES
There are 3 types of glue used in ISZ KNIVES. The strength of the material is very strong, but we focused on peel strength, elongation, high shear strength and very high weather resistance.
・For Full tang model
As a high-strength epoxy adhesive on the market for standard models.
We mainly use American best-selling epoxy adhesive, JB Weld. It has excellent weather resistance, water resistance, high shear strength, and excellent workability.
・For Concealed Models
Adopted for concealed handle. Epoxy adhesive is Cemedine EP001K.
It has very good elongation and peel strength, and the operating temperature range is -40°C to 110°C, which is perfect performance, but it has the disadvantage of low shear strength.
ISZ KNIVES achieves high shear strength by blending adhesive materials made by Japan chemical manufacturers.
It is no exaggeration to say that the performance of the concealed type, which does not rely on pins or bolts for fixing the handle, depends on the selection of a superior adhesive.
Epoxy adhesives with high performance in terms of shear strength, peel strength, elongation, weather resistance, and water resistance are ideal.
However, only a few adhesives meet such requirements, and the cost is high.
・For High-spec models
Weather resistance for scorching areas such as Antarctica to Death Valley, waterproofing of gaps due to ``bending'' of the blade. Low water absorption, high insulation, high shear strength, high peel strength, high elongation. As a structural epoxy adhesive in which these are fused at a very high level. We adopted DURALCO® 4538, which USA Cotronics boasts to the world.
It is extremely flexible yet has a strong high shear strength.
There are not so many epoxies that combine these contradictory characteristics at a high level.
Although there are epoxy adhesives that have higher adhesive strength than this, the decisive difference in performance from other manufacturers with similar performance is the overwhelming application temperature.
It can be used in a wide range from -70°C to 230°C below freezing, and this performance means ultra-high durability and high weather resistance.
DURALCO® 4538 is an epoxy adhesive that can be used in any environment on earth.
The big downside, however, is that it costs a ton of money, almost like buying a brand new smartphone.
