Hot glue is widely used in packaging, crafts, electronics assembly, woodworking, and light industrial bonding. Despite its everyday appearance, hot glue is a thermoplastic adhesive with specific melting and working temperature ranges that directly affect bond strength, safety, and application performance. Understanding these temperatures helps users choose the right glue sticks and equipment for their projects while avoiding material damage or weak adhesion.
Hot glue does not have a single universal melting point. Instead, its melting behavior depends on formulation, viscosity, and intended use. Most hot glue sticks are designed to soften gradually and become fully workable within a defined temperature range rather than melting sharply at one exact temperature.
Most standard hot glue formulations begin to soften at approximately 120°C and become fully molten between 160°C and 190°C. In this state, the adhesive flows smoothly through the glue gun nozzle and wets the bonding surface effectively. Once applied, it cools and solidifies within seconds to minutes, forming a mechanical and thermal bond.
Industrial or specialty hot melt adhesives may require higher temperatures, sometimes exceeding 200°C, to achieve optimal flow and adhesion. Conversely, low-temperature hot glue formulations are engineered to melt at significantly lower temperatures for safety-sensitive applications.
Hot glue sticks are commonly classified into low-temperature and high-temperature types. Each category serves different materials and working environments.
Low-temperature hot glue typically melts between 120°C and 150°C. It is suitable for delicate materials such as thin plastics, foam, fabric, paper, and lightweight packaging components. Because the adhesive is applied at a lower heat level, it reduces the risk of burns and material deformation.
High-temperature hot glue generally melts between 170°C and 195°C. This type is preferred for stronger bonds and more demanding applications, including wood, metal, rigid plastics, and thicker substrates. The higher temperature improves adhesive penetration and bond strength but requires greater care during handling.
Glue guns are designed to maintain adhesive temperature within a controlled range rather than simply heating until the glue melts. Low-temperature glue guns usually operate around 120°C to 140°C, while high-temperature glue guns operate between 170°C and 200°C.
Dual-temperature glue guns allow users to switch between temperature settings, making them versatile for mixed-material projects. Using the correct glue gun temperature ensures consistent flow, reduces stringing, and improves bond reliability.
| Glue Type | Softening Temperature | Working Temperature |
|---|---|---|
| Low-temperature hot glue | ~120°C | 120°C–150°C |
| Standard hot glue | ~140°C | 160°C–180°C |
| High-temperature hot glue | ~160°C | 170°C–200°C |
The melting behavior of hot glue is influenced by several factors beyond the basic formulation. Resin composition, such as EVA or polyamide, determines how quickly the glue softens and how it flows under heat. Additives can modify flexibility, open time, and heat resistance.
Environmental conditions also play a role. In colder environments, hot glue may cool and solidify faster, requiring slightly higher working temperatures. In warm environments, the adhesive may remain tacky longer, affecting positioning and set time.
Glue stick diameter can influence heat transfer as well. Thicker glue sticks may require longer preheating to reach a uniform molten state inside the gun.
Hot glue is a thermoplastic material, which means it can remelt when reheated. Once cooled, it becomes solid but will soften again if exposed to temperatures near its original melting range. This property allows hot glue to be reworked or removed with controlled heat.
However, repeated heating and cooling cycles can degrade adhesive performance. Over time, the glue may lose elasticity or bonding strength due to thermal stress and oxidation.
Selecting the correct melting temperature is essential for achieving reliable results. For lightweight bonding and heat-sensitive materials, low-temperature hot glue provides adequate adhesion with improved safety. For structural or load-bearing connections, high-temperature hot glue offers superior strength and durability.
Matching the glue type to both the material and the operating environment ensures optimal performance. Using a glue that melts too hot may damage substrates, while glue that melts too cool may fail under stress.
Molten hot glue can cause burns if it contacts skin. High-temperature formulations pose a greater risk due to their elevated working temperatures and slower cooling time. Proper handling techniques, protective gloves, and stable work surfaces reduce the likelihood of injury.
Ensuring the glue gun operates within its intended temperature range also prevents adhesive overheating, which can lead to excessive dripping, fumes, or degraded bonding performance.
Hot glue typically melts and becomes workable between 120°C and 200°C, depending on whether it is a low-temperature or high-temperature formulation. Understanding these temperature ranges allows users to select the right glue stick and glue gun for their specific needs, ensuring strong adhesion, material compatibility, and safe operation across a wide range of applications.
