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.
Adhesives Used at ISZ KNIVES
We use two types of adhesives at ISZ KNIVES. While the material is extremely strong, we prioritize high shear strength, high peel strength, high elongation, and exceptional weather resistance.
Standard Model
The standard model is a commercially available high-strength epoxy adhesive.
We primarily use JB Weld, America's best-selling epoxy adhesive. It offers excellent weather resistance, water resistance, high shear strength, and ease of use, and its performance is backed by a long track record.
The tensile strength of the concealed handle is strong enough to withstand a force of approximately 5 tons, making it difficult to break once bonded.
- For high-spec models
Weather-resistant for use in scorching hot climates like Antarctica and Death Valley, and waterproofing of gaps due to blade flexibility. Low water absorption, high insulation, high shear strength, high peel strength, and high elongation. This structural epoxy adhesive combines these qualities at an exceptional level. We selected DURALCO® 4538, the world-renowned adhesive from USA Cotronics.
It boasts exceptional flexibility yet powerful shear strength. The tensile strength of this concealed handle is approximately 4 tons.
Few epoxies can achieve such contradictory properties at such a high level.
While there are epoxy adhesives with even higher adhesive strength, the defining difference between this and other manufacturers' adhesives with similar performance is its overwhelming temperature range.
Usable over a wide temperature range, from -70°C to 230°C, this performance translates to ultra-high durability and weather resistance.
DURALCO® 4538 is an epoxy adhesive that can be used in any environment on Earth.
However, its major drawback is that it costs an exorbitant amount, roughly the same as buying a new smartphone.
