Modern manufacturing is increasingly moving toward lighter, cleaner, and more efficient assembly methods. While bolts, screws, rivets, and other mechanical fasteners remain essential in many applications, industrial adhesives and sealants are becoming an important alternative for joining, sealing, protecting, and assembling components.
The choice is not simply between “adhesive or fastener.” In many industrial applications, the best engineering solution combines adhesive bonding with mechanical fastening or uses adhesives and sealants where traditional fastening creates unnecessary weight, stress, corrosion points, or manufacturing complexity.
So, When Should Manufacturers use Industrial Adhesives Instead of Mechanical Fasteners?
This guide explains the differences, advantages, limitations, and application considerations for industrial adhesive bonding and mechanical fastening.
What Are Industrial Adhesives?
Industrial adhesives are engineered bonding materials used to join two or more substrates without relying primarily on mechanical fasteners.
Depending on the application, manufacturers can select from technologies such as:
- Silicone adhesives and sealants
- Structural adhesives
- Cyanoacrylate adhesives
- UV-curing adhesives
- Threadlockers
- Retaining adhesives
- Flange sealants
- Epoxy-based systems
- Specialty adhesives for electronics, automotive, solar, appliances, and machinery
Fasto Adhesives offers a broad industrial portfolio covering silicone compounds, cyanoacrylates, UV adhesives, threadlockers, thread sealants, flange sealants, retaining adhesives, and structural adhesives.
The choice is not simply between “adhesive or fastener.” In many industrial applications, the best engineering solution combines adhesive bonding with mechanical fastening or uses adhesives and sealants where traditional fastening creates unnecessary weight, stress, corrosion points, or manufacturing complexity.
So, When Should Manufacturers use Industrial Adhesives Instead of Mechanical Fasteners?
This guide explains the differences, advantages, limitations, and application considerations for industrial adhesive bonding and mechanical fastening.
What Are Mechanical Fasteners?
Mechanical fasteners physically hold components together. Common examples include:
- Bolts and nuts
- Screws
- Rivets
- Washers
- Pins
- Clips
- Studs
Mechanical fastening is well established because it provides predictable clamping force and, in many applications, allows components to be disassembled.
However, fasteners can introduce holes, concentrated stresses, additional components, corrosion points, and extra manufacturing operations.
Industrial Adhesives vs Mechanical Fasteners
The right joining technology depends on the application, substrates, environmental conditions, production process, and required service life.
Factor | Industrial Adhesives | Mechanical Fasteners |
Load distribution | Distributed across bonded area | Concentrated around fastener |
Appearance | Clean, seamless appearance | Visible hardware may remain |
Weight | Can reduce hardware | Adds fastener weight |
Drilling | Often unnecessary | Usually required |
Vibration | Flexible systems can absorb movement | May loosen under vibration |
Sealing | Can bond and seal simultaneously | Usually requires additional sealing |
Dissimilar materials | Can join many combinations | May require special hardware |
Disassembly | Depends on adhesive chemistry | Generally easier |
Automation | Suitable for automated dispensing | Can require mechanical assembly |
Corrosion risk | No drilled fastening holes | Fastener and hole can create corrosion concerns |
The important point is that adhesives are not simply replacements for screws and bolts. They provide a different engineering approach to joining and protecting components.
1. Adhesives Can Distribute Stress More Evenly
A mechanical fastener transfers load through a relatively concentrated area around the hole and fastener.
An adhesive joint can distribute load across a much larger bonding surface.
This can be particularly useful when joining:
- Thin sheet materials
- Glass
- Aluminium
- Plastics
- Composite materials
- Painted surfaces
- Dissimilar substrates
For applications involving vibration, thermal movement, or flexible substrates, an appropriately selected adhesive can help accommodate movement instead of creating a rigid point connection.
2. Adhesives Can Bond and Seal at the Same Time
One of the biggest advantages of sealants and adhesive-sealant systems is that they can perform multiple functions.
A silicone sealant, for example, can provide:
Bonding + sealing + flexibility + environmental protection
Silicone compounds are commonly used for waterproofing, gap filling, bonding, glazing, electrical insulation, and protection from environmental exposure.
This can be particularly valuable in:
- Solar modules
- Electrical enclosures
- LED assemblies
- Automotive components
- Industrial machinery
- Appliances
- Outdoor equipment
3. Adhesives Eliminate Many Drilling Operations
Mechanical fastening frequently requires holes to be drilled, punched, or otherwise created in the substrates.
Adhesive bonding can eliminate these operations when the joint design allows it.
This may help manufacturers reduce:
- Drilling time
- Fastener inventory
- Assembly steps
- Hole-related damage
- Surface deformation
- Additional sealing requirements
For high-volume manufacturing, eliminating even one assembly operation can have a meaningful effect on production efficiency.
4. Adhesives Are Useful for Dissimilar Materials
Modern products increasingly combine different materials to achieve lower weight, improved appearance, thermal performance, electrical properties, or corrosion resistance.
Examples include:
- Aluminium + glass
- Metal + plastic
- Glass + composite
- Rubber + metal
- Plastic + electronics
- Aluminium + painted surfaces
Mechanical fasteners can create challenges when different materials have different coefficients of thermal expansion or when galvanic corrosion becomes a concern.
An appropriately selected adhesive can provide a continuous interface between dissimilar substrates while accommodating some degree of movement.
5. Adhesives Can Improve Vibration Resistance
Industrial equipment, automotive systems, agricultural machinery, transportation equipment, and electrical assemblies can experience continuous vibration.
Mechanical joints may require additional measures to prevent loosening.
Adhesive technologies such as threadlockers can complement conventional fasteners by securing threaded assemblies and reducing the risk of vibration-induced loosening.
This is particularly useful in machinery where maintenance, downtime, or unexpected fastener movement can affect operational reliability.
Adhesives and Fasteners Can Work Together
Industrial equipment, automotive systems, agricultural machinery, transportation equipment, and electrical assemblies can experience continuous vibration.
Mechanical joints may require additional measures to prevent loosening.
Adhesive technologies such as threadlockers can complement conventional fasteners by securing threaded assemblies and reducing the risk of vibration-induced loosening.
This is particularly useful in machinery where maintenance, downtime, or unexpected fastener movement can affect operational reliability.
Where Industrial Adhesives Are Commonly Used
Solar Energy
Solar modules are exposed to UV radiation, moisture, temperature changes, wind loads, and long-term outdoor conditions.
Adhesives and sealants can be used for:
- Aluminium frame sealing
- Glass-to-frame interfaces
- Junction box bonding and sealing
- Cable-entry sealing
- Electrical protection
- Weatherproofing
Fasto’s solar portfolio includes Fasto SM30 solar frame sealant and Fasto SP70 solar-grade junction box potting compound, alongside other solutions for solar manufacturing and installation.
Automotive
Automotive assemblies can experience:
- Vibration
- Temperature cycling
- Oil exposure
- Moisture
- Mechanical loads
Specialized silicone sealants can be used for demanding flange and sealing applications. For example, Fasto S990 is designed for automotive and industrial sealing applications requiring oil tolerance, flexibility, and resistance to mechanical stress.
Electronics and LED Lighting
Electronic components require protection from:
- Moisture
- Dust
- Vibration
- Electrical exposure
- Thermal cycling
Potting compounds, silicone adhesives, and sealants can protect sensitive components while providing electrical insulation.
Industrial Machinery
Machinery often combines metal components that experience vibration, thermal expansion, oil exposure, and continuous operation.
Depending on the joint, manufacturers can use:
- Threadlockers
- Retaining adhesives
- Flange sealants
- RTV silicone sealants
- Structural adhesives
For high-temperature applications, Fasto S960 is a high-performance RTV silicone sealant designed for sealing, bonding, and glazing applications exposed to elevated temperatures.
How to Choose Between an Adhesive and a Fastener
Before selecting a joining method, engineers should evaluate the following factors.
1. Substrate
Identify exactly what materials are being joined.
Consider:
- Metal type
- Plastic type
- Glass
- Rubber
- Composite
- Painted or coated surfaces
2. Operating Temperature
Determine the minimum and maximum temperatures expected during production, transportation, and operation.
For high-temperature applications, a general-purpose adhesive may not be appropriate.
3. Environmental Exposure
Consider whether the joint will experience:
- Water
- Humidity
- UV radiation
- Chemicals
- Oils
- Dust
- Salt
- Outdoor exposure
4. Mechanical Loads
Evaluate:
- Tensile loads
- Shear loads
- Peel forces
- Compression
- Vibration
- Impact
- Thermal expansion
5. Production Requirements
The adhesive selection should also match the manufacturing process.
Consider:
- Cure time
- Application method
- Automation
- Dispensing equipment
- Surface preparation
- Production volume
- Required handling strength
6. Serviceability
If the assembly must be regularly dismantled, mechanical fastening may be more appropriate.
If permanent bonding is preferred, an adhesive or adhesive-plus-fastener solution may provide advantages.
Why Sealant Selection Matters
Not every silicone sealant is suitable for every application.
For example, Fasto’s silicone portfolio includes general-purpose RTV products, neutral-cure systems, high-temperature sealants, automotive flange sealants, gap-filling sealants, and specialized solar solutions.
Neutral-cure silicone can be particularly useful where non-corrosive behavior toward metals and sensitive substrates is important. Fasto S887, for example, is designed as a one-part neutral-cure RTV silicone for bonding, sealing, and glazing applications across electrical, mechanical, automotive, and construction sectors.
The correct product should therefore be selected based on the actual substrate, environmental exposure, joint design, curing requirements, and performance expectations.
Common Mistakes When Selecting an Industrial Adhesive
Choosing Only by Adhesive Strength
A high-strength adhesive is not automatically the best adhesive.
The joint may fail because of:
- Poor surface preparation
- Incorrect adhesive chemistry
- Excessive peel stress
- Temperature exposure
- Chemical exposure
- Incorrect joint design
Ignoring Surface Preparation
Dust, oil, moisture, release agents, oxidation, and other contaminants can significantly affect adhesion.
Surface preparation should be defined according to the adhesive and substrate.
Using the Same Sealant Everywhere
A general-purpose RTV sealant may work well for one application but may not be suitable for high-temperature, oil-exposed, electrical, or solar applications.
Focusing Only on Initial Bond Strength
Industrial products need to perform throughout their service life.
Engineers should evaluate:
Initial performance + environmental resistance + ageing + flexibility + application process
rather than selecting a product based solely on its initial bond strength.
The Future of Industrial Assembly
The growth of lightweight materials, automation, renewable energy, electronics, electric mobility, and advanced manufacturing is increasing the importance of engineered bonding and sealing technologies.
Adhesives can help manufacturers design assemblies that are:
- Lightweight
- More compact
- Better sealed
- Easier to automate
- Resistant to vibration
- Suitable for dissimilar materials
- Cleaner in appearance
At the same time, mechanical fasteners remain essential for applications requiring immediate mechanical fixation, inspection, adjustment, or disassembly.
The future of industrial assembly is therefore unlikely to be adhesives versus fasteners.
Instead, it is increasingly about selecting the right joining technology—or combination of technologies—for each application.
Why Choose Fasto Adhesives?
Fasto Adhesives develops industrial bonding and sealing solutions for applications across solar energy, automotive, transportation, agricultural machinery, LED lighting, appliances, and industrial machinery.
Its product portfolio includes silicone compounds, structural adhesives, cyanoacrylates, UV adhesives, threadlockers, retaining adhesives, thread sealants, and flange sealants.
For manufacturers, the objective should not simply be to find an adhesive.
It should be to identify a joining and sealing solution that matches the substrate, production process, environmental conditions, mechanical requirements, and expected service life.
Frequently Asked Questions
Neither is universally stronger. Performance depends on joint design, materials, loads, adhesive chemistry, fastener design, and operating conditions.
In some applications, yes. In others, mechanical fastening remains necessary. Hybrid adhesive-and-fastener systems can often provide an effective solution.
Some silicone formulations provide both bonding and sealing capabilities. However, the product must be selected according to the required bond strength, substrate, joint design, and environmental conditions.
Certain formulations are specifically designed for outdoor exposure. Silicone sealants, for example, can provide weather and UV resistance when the appropriate grade is selected.
There is no single best adhesive for every application. The appropriate product depends on the substrates, temperature, environmental exposure, mechanical loads, curing requirements, and production process.
Start with the substrate and application conditions, then evaluate temperature, moisture, UV exposure, chemical exposure, mechanical stress, cure requirements, and desired service life. Fasto's product range covers multiple adhesive and sealant technologies for different industrial requirements.
