Comparing Adhesive Techniques vs. Welding
Adhesive bonding and welding are two widely used methods for joining metal substrates. Welding has long been the traditional choice, offering robust, permanent bonds through heat and fusion. However, adhesives are becoming increasingly popular across industries due to their versatility.
In this blog, we will explore key differences between these methods, focusing on joining mechanisms, material compatibility, joint strength, and flexibility. By understanding how these factors affect performance, you’ll be better equipped to choose the right bonding solution for your specific application
A] Introduction To Epoxy Adhesive Bonding
Epoxy adhesives are versatile glues used to bond materials like metal, ceramics, wood, rubber, glass, and plastic. They create strong, reliable bonds by forming a durable cross-linked chemical structure upon curing at ambient or elevated temperatures or upon exposure to UV light. Known for their durability, epoxy adhesives ensure durable connections in varying conditions. Structural adhesives also help evenly distribute stress across surfaces, reducing concentration points. Moreover, adhesive bonding is faster, more flexible, and requires less specialised expertise compared to other methods, making it a preferred choice in many industries.
B] Understanding Welding
Welding is a traditional method of joining metals or thermoplastics by fusing two or more parts using heat, pressure, or both. While this process offers strong bonds, it also generates significant heat, which can weaken the structural integrity of the materials. This thermal impact can make the welded parts more susceptible to failure under high-stress conditions, highlighting a key limitation of welding. The process is often unsuitable for delicate materials or applications requiring high precision and durability.
C) Difference Between Adhesive Techniques and Welding
| Category | Adhesive Techniques | Welding |
|---|---|---|
| Joining Mechanism | Adhesive techniques offer a simple process to bond the two or more substrates together. In this process, metal bonding glue is uniformly applied to the substrate’s surface by positioning them firmly. Then the substrates are pressed using clamps or weight to maintain pressure during the curing process. | Welding is a more intricate process of joining the substrates together. It joins the materials by fusing the edges of the substrates by melting them first. The welded material further goes into the cooling process to solidify the joint. |
| Heat Generation | Adhesives don’t generate any extensive heat during the application process. However, the heat-curing epoxies require a minimal to moderate amount of heat to initiate the bonding process. Some epoxy glues have good thermal conductivity and high-temperature resistance, allowing the bond to strongly withstand extreme temperatures. | Welding generates lots of heat during the joining process. The high amount of heat melts the edges of substrates and helps in the fusion process. However, sometimes high heat changes the geometrical and structural integrity of the substrate, this then needs to be addressed separately. |
| Material Compatibility | Adhesives offer a wide range of material compatibility such as metal, ceramics, composites, rubber, glass and plastic. Epoxy adhesives efficiently bond these substrates, providing a strong bonding solution. In addition, epoxies can be customised to suit the specific substrate compatibility and bonding strength. | Welding offers a limited range of substrate compatibility. Only metals are joined together through the welding process while welding thermoplastic is rare but possible. The intricate and limited substrate compatibility is one of the leading drawbacks of this process. |
| Joint Strength And Flexibility | Structural adhesives are known for their robust and reliable bonding. Its high shear strength and toughness efficiently redistribute the load, offering more reliable and flexible bonding solutions for diverse industries. Metal-to-metal adhesives are a good alternative to welding. | Welding can form strong and permanent joints. When parent materials are joined using welding, they create continuous joints. Welds are not flexible and can become brittle under certain conditions. In addition, welding joints are more prone to corrosion. |
D] Adhesive Vs Welding: Pros And Cons
Welding is known for its durability and strength. Meanwhile metal-bonding epoxy adhesives are emerging as a powerful contender. However, both have some fair share of pros and cons which are illustrated below:
| Bonding Technique | Pro’s | Con’s |
|---|---|---|
| Adhesive | Modern adhesives are incredibly strong and powerful and can create superior bonds between similar or dissimilar substrates. With sufficient surface preparation, they efficiently bond hard-to-bond substrates such as low-surface energy plastics, metals, and composites. They are also able to evenly distribute the stress across the bonded surface for concentrated stress points. Additionally, No sparks or vision hazard protection equipment is needed during the application process. | Adhesives require precise weighing, mixing, and a comprehensive surface preparation to create a strong and long-lasting bond. Clean and nicely prepared surfaces raise the surface energy and give a needed resistance for the optimal bonding between substrates. |
| Welding | Welding is a traditional and well-known metal joining solution. Common applications include boilers and engine welding applications. Welded joints can withstand high temperatures and load while effectively handling high-stress environments. | Welding’s high heat can damage thin and sensitive to temperature materials. It often works best with similar materials. Dissimilar materials can be tricky or impossible to join. It also requires extensive safety precautions due to sparks, fumes, and molten metal. In addition, weldings leave a permanent mark on the materials, which may not be aesthetically suitable. Welding requires significant skill and training to operate safely and effectively. |
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E] Adhesive Vs Welding: Strength, Durability & Flexibility
Adhesives or welding, choosing the best techniques for industrial applications lies between the three key factors: strength, durability, and flexibility.
1. Strength
Modern epoxy adhesives distribute stress more evenly, while welding creates strong, concentrated joints. For high-stress applications, welding provides unmatched shear strength. However, adhesives can provide on-par strength, particularly when bonding dissimilar materials.
2. Durability
Adhesives are highly durable, offering resistance to corrosion, chemicals, and high temperatures. Welded joints, while strong, are more susceptible to environmental degradation, such as rust and corrosion.
3. Flexibility
Adhesives offer excellent flexibility and can absorb vibrations, making them ideal for applications requiring shock absorption. Welding, on the other hand, creates rigid, non-flexible joints that are more likely to fail under fluctuating stresses.
F] Panel Bonding Using Adhesive Vs Welding:
Method Both adhesives and wielding offer reliable panel bonding solutions. However, with the advancement in adhesive technology, adhesives are now a better option for panel bonding. Here’s why:
- Invisible Seams: Unlike welding’s visible seams, adhesives create a smooth, seamless finish, making it ideal for aesthetic applications.
- Heat-Sensitive: Adhesives eliminate the chances of damage to thin or heat-sensitive materials like plastics or composites.
- Effectively bonds dissimilar substrates: Adhesives bond dissimilar materials like metal to plastic, which can be tricky or impossible with welding.
- Uniform stress distribution: Modern adhesives distribute stress evenly across the entire joint, conversely, welding concentrates stress in specific points.
- Vibration Absorption: Adhesives can dampen vibrations between panels, making them ideal for noise reduction in applications like automotive parts or housings.
G] Best Epoxy Adhesives For Metal Bonding
- TUF 1820 AOHT: TUF 1820 AOHT is a single-component epoxy system that cures within an hour at 120°C or above. It easily bonds to metal and provides phenomenal bonding and mechanical strength properties, as well as dimensional stability. It is perfectly suited for electronics, optoelectronics, aerospace, and the OEM industry.
- TUF 1621 AOHT: TUF 1621 AOHT is a two-component epoxy system that is suitable for bonding, coating, and sealing. It offers remarkable toughness and superior peel strength and is resistant to several chemicals.
- KB 1040-2: KB 1040-2 can be used for bonding, sealing, coating, encapsulation, and potting a variety of substrates, including metal. It offers excellent mechanical strength, resistance to a variety of chemicals, and dimensional stability.
- KB 1031 SPLV-6: KB 1031 SPLV-6 is a two-component epoxy system widely used in electronics, aerospace, electrical, optical and various OEM applications. It bonds well to similar and dissimilar substrates with varying coefficients of thermal expansion and offers exceptional mechanical strength.
- KB 1039 CRLP: KB 1039 CRLP is a two-component, heat-curing epoxy system. It is used in optical, optoelectronic, electronics and aerospace industries. It offers outstanding mechanical strength, a very low shrinkage upon cure, and excellent flow properties.
Related Products
TUF 1820 AOHT
Kohesi Bond TUF 1820 AOHT is a noteworthy toughened, single component epoxy system that requires no mixing and offers an unlimited working life at room temperature. It cures in merely 60 – 70 minutes at 120°C and even faster at higher temperatures. Read More
TUF 1621 AOHT
Kohesi Bond TUF 1621 AOHT is a two component, room temperature curing epoxy system suitable for bonding and sealing. It is capable of passing NASA standards for low outgassing (ASTM E-595) and has a convenient 1:1 (Part A: Part B) mix ratio by weight or volume. This unique epoxy system offers remarkable toughness and superior peel strength. Read More
KB 1040-2
Kohesi Bond KB 1040-2 is a two component, room temperature curing epoxy system suitable for bonding, sealing, coating and encapsulating applications. It has a favorable 10:1 (Part A: Part B) mix ratio by weight. The highlight of this products is its superior optical clarity and its capability of passing NASA low outgassing test. Read More
KB 1031 SPLV-6
Kohesi Bond KB 1031 SPLV-6 is a two component epoxy system for bonding, sealing, coating and encapsulating. It has a convenient 1:1 (Part A: Part B) mix ratio by weight or volume. This high performance specialty product offers a unique combination of low viscosity, low exotherm and very long working life. Read More
KB 1039 CRLP
Kohesi Bond KB 1039 CRLP is a two component, heat curing epoxy system suitable for bonding, sealing, coating, potting and encapsulation. It has a favorable 100:65 (Part A: Part B) mix ratio by weight. Read More
Wrapping Up
Both adhesive bonding and welding offer their own sets of benefits. Adhesives provide versatility, ease of use, and the ability to bond various materials, while welding offers high-strength bonding for specific metal applications. Your choice between these methods should depend on your project’s specific requirements.
Kohesi Bond is a leading brand in the adhesive industry, offering high-quality epoxy adhesives for various industrial applications. Contact us today to explore future-proof bonding solutions for your projects!
FAQs
Adhesives are an incredibly versatile, robust, and reliable solution that offers high-strength and long-lasting bonds. While welding offers high-strength bonding for some specific industrial applications.
Structural epoxy adhesives offer on-par or better bond strength than welding. They are considered the best adhesives for metal in diverse metal bonding applications.
Adhesives can bond most materials, such as metals, plastic, ceramics, and composites, showcasing one of the major advantages that other joining methods lack.
No, both methods of bonding are entirely different. Welding joins metals by melting the edges, fusing them, and then cooling them to form one continuous structure, while adhesive bonds the substrates without any such complex requirements.
Yes, epoxies are a great alternative for creating reliable bonds even with dissimilar materials. It is a safe, easy, and versatile option for bonding substrates. However, a detailed knowledge of the project’s requirements is essential when choosing epoxy adhesives instead of welding.
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Utsav Shah is a 34-year-old entrepreneur with a passion for scientific discovery. Utsav’s journey began with a deep dive into materials science, earning degrees from USC and the Institute of Chemical Technology. He’s the visionary founder of Kohesi Bond, a top-rated adhesive manufacturer, and Cenerge Engineering Solutions, a leader in heat exchangers and cryogenic pumps. With over a decade of experience, Utsav consults across various industries, ensuring they have the perfect adhesive solution for their needs. Connect with him on LinkedIn!
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