Why metal Glue / adhesive ?

Using metal glue offers numerous benefits for bonding metal surfaces, making it an essential tool . Whether you’re repairing, assembling, or crafting, metal glue provides a strong, durable bond without the need for specialized equipment like welding or rivets.

Here are some reasons why metal adhesive is a great choice:

1. Strong and Durable Bonds

  • Metal glues, particularly epoxy or acrylic-based adhesives, create high-strength bonds that can withstand heavy stress, making them ideal for structural and industrial applications.

2. No Need for Specialized Equipment

  • Unlike welding or riveting, which require expensive tools and technical skills, metal glue is easy to use and can be applied with minimal equipment. This makes it ideal for DIY enthusiasts, home repairs, or small-scale manufacturing.

3. Versatile Applications

  • Metal glue can be used on a wide range of metal surfaces, including steel, aluminum, copper, and even mixed materials like metal and plastic. It is useful in automotive repairs, construction, appliances, arts, and crafts.

4. Flexibility and Impact Resistance

  • Many metal glues remain flexible once cured, which helps them resist cracking under pressure or vibration. This flexibility is crucial in applications where the metal expands and contracts with temperature changes.

5. Time and Cost Efficiency

  • Metal adhesive often sets faster than traditional welding or bolting methods, reducing downtime. It’s also a more affordable solution, especially for smaller projects or quick repairs.

6. Clean and Professional Finish

  • Metal glue allows for a clean bond without the need for visible fasteners. This is particularly important for applications where aesthetics matter, such as in furniture, decorative items, or automotive bodywork.

7. Resistance to Environmental Factors

  • High-quality metal adhesives are resistant to moisture, temperature fluctuations, chemicals, and UV exposure, making them perfect for both indoor and outdoor applications.

8. Gap Filling Capability

  • Some metal glues are designed to fill gaps between surfaces, providing a seamless bond even when there is a slight misalignment or space between metal pieces.

9. Minimal Maintenance

  • Once applied and cured, metal glue requires little to no maintenance. Unlike mechanical fasteners that can loosen over time, metal glue bonds are typically stable and long-lasting.

10. Easy Application

  • Most metal glues are easy to apply, whether you’re using a syringe, brush, or applicator. Many adhesives cure quickly or can be accelerated using heat, ensuring a fast and efficient bonding process.
construction adhesives
liquid nails adhesive
metal glue
strong hybrid adhesive

Applications of Metal Glue:

  1. Automotive Repairs:

    • Repair cracked metal parts, exhaust systems, or bodywork without the need for welding.

  2. Home and Construction Projects:

    • Bond metal fixtures, fittings, and hardware in home improvement and construction tasks.

  3. DIY and Craft Projects:

    • Perfect for small metal-based projects, such as jewelry-making, metal art, or crafting.

  4. Industrial and Manufacturing:

    • Used in machinery repair, electronics, and appliance assembly where a high-strength, precise bond is required.

Metal-Bonding Adhesive vs Welding

Welding is a very common technique for metal-to-metal assembly operations, and in some ways using adhesive for metal is very similar. For example, the lack of protruding fastener heads gives both welded parts and glued metal parts a more streamlined appearance.

However, welding also has a number of disadvantages that would not apply to a metal-to-metal adhesive bonds.

Welding introduces many complications and problems which often aren’t immediately visible.

  • Thermal distortion – Every weld pulls and distorts the final product and can cause cracking.
  • Welder skill – Anybody can bolt two pieces of metal together but even the simplest welding requires skilled labour or automation
  • Variables which change with material and joint type – Welding mild steel is fairly straightforward but if you are welding a high alloy steel or, other metals you will need someone who knows what they are doing. These variables include:
    • Voltage, current, wire feed speed, travel speed
    • Heat input
    • Filler metal
    • Preheat, post heat, inter-pass temperature
    • Process
    • Shielding gas, flux
    • Hydrogen control
    • Mechanical weld adjustments – Grinding, peening
  • Ability to join dissimilar metals is limited at best
  • Many problems are not visible – Testing methods are used to find these discontinuities. The main four are liquid penetrant and magnetic particle for finding surface or near surface problems and ultrasound and radiography to find subsurface problems. All these methods require skilled labour.

In contrast, most adhesive products can be correctly applied with minimal training. This translates to more consistent quality and lower overall production cost.

Find out more about the adhesive products( metal bonding in India) that can replace costly welding by signing up here.

Metal glue-Bonding Adhesives vs Fasteners 

Fasteners such as bolts and screws are very common methods of bonding for temporary joints. Fasteners are also suitable for semi temporary joints such as those in automotive assemblies. Nevertheless, problems may occur as fasteners require carefully placed holes, are prone to corrosion and may loosen over time.

This is where metal bonding adhesive come into picture: removable adhesives and tapes are suitable for temporary bonding, and they do not leave traces behind after removal. Adhesives are also suitable for semi temporary joints as they seal from corrosion, are generally lighter and cheaper than mechanical fasteners, and distribute the stress throughout the bond making the assembly stronger. Some metal bonding adhesives come with special properties such as chemical resistance and heat resistance. Heat resistant glue for metal is common in public transport vehicles, automotive industry and general industrial applications. Metal glue can also be used for supporting fasteners: threadlocking and thread sealing are common applications where a metal glue makes sure the fastener does not loosen over time.

If your design uses fasteners, click here to receive more information about other adhesive options.

Call us for Metal Bonding in India.

Call / Whatsapp- +91 9699892782 for metal to metal glue

Types of metal glue

    1. Epoxy adhesive is one of the strongest adhesives for metal. It exists in different types which have unique properties such as chemical resistance and heat resistance. Epoxies come as one or two component systems. Single component epoxy glue for metal cures as a result of additional heat. A 2K system is a mixture of two parts with react with each other starting the curing process. When looking for the strongest glue for metal, a 2K epoxy for metal should be considered.

    Limitations of epoxy adhesiives:

    • 2 part mixing is messy, time-consuming, not suitable for continuous production.
    • Epoxy is brittle by nature, can’t take vibrations or flexing
    • labour intensive, application cannot be automated
    • 2 part cartridge requires special gun applicator and still not user friendly.
    • it has a typical smell

2. Acrylic adhesive metal glue exists as two types: surface activated and and bead on bead acrylics. The latter refers to applying a bead of adhesive on both substrates before connecting them. The bonding starts when the parts come in contact with each other and become subject to pressure. Surface activated acrylics, in turn, require a water thin initiator applied to one substrate and the resin to the other.

Limitations:

  1. 2part system- time consuming, not friendly for high speed production lines.
  2. limited flexibility, joints cannot be subjected to flexing
  3. adhesive cost is high
metal bonding

3. Cyanoacrylate, also known as instant adhesive, is the super glue for metal to metal bonding. Cyanoacrylate adhesives is suitable for most metals as long as they are reactive.

Limitations:

  1. brittle bondline after curing, cannot be subjected to joint movement and flexing
  2. debonds or bond fails if in contact with water continuously
  3. health hazard- bonds to skin instantly, while curing it emits vapours with a strong smell, eye irritant
  4. not suitable for large bonding areas, cannot fill high gaps ( > 1 mm)
metal bonding adhesive

4. Anaerobic metal adhesives are only used for glueing metal to metal as they require the presence of metal and absence of oxygen to be able to cure. Anaerobic adhesives are ideal for securing fasteners in terms of thread-locking and thread sealing as well as gasketing and retaining. 

Limitations:

  1. cannot be used for high gap fill applications eg: sheet metal bonding
  2. cured adhesive is not flexible so cannot withstand flexing and joint movement.
  3.  Suitable only for specific engineering application only. Not suitable for typical large surface area bonding
  4. Doesn’t work with non-metal substrates
anaerobic threadlocker

5. Polyurethane sealant and adhesive : PU sealants are excellent  for bonding / sealing metal to metal joints. In fact, in India, it is a popular adhesive used as a bodysealant for busbody manufacturing. It has high elongation, flexibility, bonds well on  metals, paintable and at affordable cost too.

Limitations:

  1. Need to protect from UV light.
  2. contains solvents, not VOC free.

Supex PU 25: Moisture cure sealant suitable for metal bonding.

  • Hardness (ASTM D 53505): 40±5 Shore A
  • Elongation at Break(DIN 53504): ≥ 500%
  • Modulus 100 % (DIN 53504): > 0,4 Mpa
  • Tensile Strength: 10 N/mm2
polyurethane sealant India

6. MS polymer adhesive : This chemistry was developed to combine the weathering/ environment resistance of Silicones and high gap fill, flexibility, paintability of Polyurethanes. Also it is solvent and Isocyanate free, high strength with high elongation, paintable, UV resistant. It is a verstile bonder and bonds to most building material and engineering substrates except telfon, PP, HDPE, LDPE. This technology is already a dominant player in Japan, gathering pace in  USA, Europe. It is widely used for automotive, Industrial and construction applications.

Limitations:

  1. Product cost is higher than Silicone or polyurethane sealants.
  2. Temperature resistance, works up to 100 C.  is lower than RTV Silicones.

Supex Bond All HT – One part, moisture cure, modified silane, flexible, high bond strength, UV resistant, VOC free weather resistant, works underwater, high tack,  verstile adhesive.

Supex Bond All HT 500

Bonding Metal to Metal

Structural adhesives can also be applied quickly and easily, such as with a dispensing gun, though they require curing time before the bond reaches full strength. Using faster, simpler assembly techniques can reduce labor and training costs, consequently reducing physical demands on human workers.

Another advantage of using adhesives in metal-to-metal applications is that they seal, potentially eliminating unnecessary steps in the assembly process. This seal can even be flexible, allowing for relative movement of parts without weakening the bonds. This makes adhesives suitable for applications involving temperature changes, weather and vibration, such as with many automotive and consumer goods.

The number of instances where adhesively bonding metal to metal is the most cost-effective solution may surprise you. 

Surface Preparation for Metal Adhesive Bonding process

Selecting the best adhesive for your metal-to-metal application can be difficult. Different metals subjected to different environmental conditions will consequently behave very differently. As a result, there is no such thing as the strongest adhesive for bonding metal. That’s why it’s important to choose the right adhesive based on a number of design considerations.

Most metals have relatively high surface energy, allowing adhesives to wet the surface and thereby improving bond strength. However, painted and powder-coated metals present a different surface.

On a painted surface, the adhesive is not bonding to the metal but instead to the paint coating. Nevertheless, it’s possible to achieve a successful bond to the metal or its surface coating, depending on the bond strength you need. One option is to mask the mating surfaces before coating, preserving the metal surface. Another is to choose an adhesive solution appropriate for bonding directly to the painted metal.

A “powder coat” is an electrostatically applied resin to a metal surface, heat-cured to form a solid layer. Powder coats are significantly more difficult to bond than paint because they often present a lower-surface-energy substrate. This will affect the adhesive you choose. 

Adhesives form the best bond to clean, dry, oil-free surfaces, including oils from workers’ hands touching the surface.

It’s also important to consider the surface condition of your substrates. Rough surfaces can make for stronger mechanical bonds by increasing the surface area of the joint or removing residual contaminants much better than cleaning alone.

However, this benefit is only realized if the adhesive can penetrate the small cracks and fissures and wet the entire surface. A bonding tape, for example, is not able to wet deep inside cracks or around raised scratches of aggressively abraded surfaces. Therefore, a liquid adhesive is best for highly abraded surfaces. Metal Bonding in India – Which Process?

When selecting a method for metal-to-metal bonding, the most important thing to keep in mind is how your chosen method will fit into your assembly process.

Are you looking for a solution that will fit into your current workflow, or can the workflow change to accommodate the new solution?

In addition to assembly considerations, you should also think about how the final product will be used.

All of these considerations—the assembly process, end use and overall cost—need to be taken into account when selecting an adhesive for metal bonding.

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Summary
Article Name
Can we replace welding, riveting with Adhesive Bonding for metal
Description
Welding is a very common technique for metal-to-metal assembly operations, and in some ways using adhesive for metal is very similar. For example, the lack of protruding fastener heads gives both welded parts and glued metal parts a more streamlined appearance. However, welding also has a number of disadvantages that would not apply to a metal-to-metal adhesive bonds. Welding introduces many complications and problems which often aren’t immediately visible. Thermal distortion – Every weld pulls and distorts the final product and can cause cracking. Welder skill – Anybody can bolt two pieces of metal together but even the simplest welding requires skilled labour or automation Variables which change with material and joint type – Welding mild steel is fairly straightforward but if you are welding a high alloy steel or, other metals you will need someone who knows what they are doing. These variables include:
Author
Publisher Name
Anagha asf llp
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