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Last Updated on February 20, 2026

Rubber to substrate bonding is used across industries like automotive, medical, and utilities to create strong, reliable and long-lasting components. To get a reliable bond, it’s important to choose the right rubber to substrate adhesives and apply it correctly. In every case, the integrity of the rubber to substrate bond is critical to product performance.

For example, rubber to substrate adhesives are often used to attach elastic seals to metal housing in auto and industrial equipment. These adhesives allow elastomeric components to bond securely to rigid surfaces, like metal. The right adhesive selection, combined with proper application, ensures the bond remains strong, enhances product performance, and extends service life.

Why DuPont Adhesives?

DuPont rubber to subsrate adhesives provide the strength and reliability needed for even the most demanding rubber-to-substrate bonding (RTSB) requirements. For 20 years, these adhesives have been made without lead, which improves workplace safety, simplifies handling and disposal, and supports global regulations and corporate sustainability goals.

Even the best adhesive won’t perform if it’s not handled properly. Incorrect preparation and application can lead to bond failure, product malfunction, and potential harm for employees and customers.

This blog shares practical tips for selecting the most suitable rubber to substrate adhesives, preparing substrates, and applying the adhesive correctly to ensure strong, durable bonds every time.

1. Choosing the right DuPont rubber to substrate adhesive

The first step to a strong, durable bond is selecting the proper DuPont adhesive. Your choice affects the performance, durability, and safety of the final assembly. DuPont offers a variety of adhesive formulations designed to work with specific materials, operating conditions, and application methods.

The experts at H.M. Royal can help recommend the right rubber to substrate adhesives for your application based on its performance for your specific elastomer — whether it be rubber, polyurethane or something else. We consider factors like substrate compatibility, bond strength, chemical and temperature resistance and curing requirements. In addition, we lab test the performance of each adhesive with your specific elastomer and provide the data to support our recommendations.

2. Maintaining proper storage conditions

Once you’ve selected the right adhesive, proper storage is the vital step to achieving consistent, high-quality bonding. DuPont adhesives should be kept sealed and in a dry environment when not in use. Generally, they should be stored between 60 °F and 80 °F. Following these storage guidelines helps preserve adhesive performance and ensures reliable results every time.

3. Mixing Adhesive

Proper mixing is essential to making sure an adhesive performs reacts as intended, spreads evenly, and forms a strong, reliable bond. Thorough mixing also helps prevent common issues like air bubbles or lumps that can weaken adhesion.

For the best mixing results, H.M. Royal recommends using a propeller-style mixer operating at 60 RPM or higher, depending on the adhesion technology. Always ensure staff wear appropriate personal protective equipment, such as gloves and safety glasses, and mix adhesives thoroughly in a well-ventilated location.

Be sure to follow the mixing instructions in the technical data sheet that outline ratios and speeds. Following instructions is essential to avoiding cross-contamination and achieving optimal bond strength.

4. Determining optimal viscosity, dilution ratio and dry film thickness

Before application, be sure to determine the right viscosity, dilution ratio, and dry film thickness for the specific rubber to substrate application. 

Viscosity

The ideal viscosity depends on your application method. Spraying requires a lower viscosity, while dipping and brushing works best with a thicker adhesive.  Estimate the static viscosity of your adhesive using a Zahn cup. At H.M. Royal, we can measure the dynamic viscosity of your adhesive using a Brookfield viscometer

Dilution ratio

Adjusting viscosity of the adhesive requires proper dilution. Always refer to the technical data sheet for approved diluents and recommended dilution ratios.  Deviating from these guidelines can compromise bond strength and lead to inconsistent results.  

Dry film thickness

Dry film thickness plays a critical role in bond performance and is closely tied to how diluted the adhesive is. Measuring it requires specialized instrumentation.

With advanced equipment and technical expertise, H.M. Royal can provide reliable recommendations for viscosity, dry film thickness, and dilution ratio.

5. Choosing the best application method

Next, choose the application method that best fits your process, whether it’s brushing, spraying, dipping, or another method. The right application method depends on factors like cost, part size, application complexity, and desired production speed. 

Spraying

Spraying offers high throughput and is often the fastest option for rubber to substrate bonding.  However, it comes at a higher cost and requires careful control. A lower-viscosity adhesive is recommended, and overspray should be minimized to prevent material waste

Dipping

Dipping is a simpler method that can be automated for higher production volumes.  It often provides better material usage efficiency than spraying but requires proper viscosity so that the adhesive remains on the substrate after removal from the vat.

Brushing

Brushing is the most time-consuming method but allows for precise application in tight or complex areas. For intricate parts requiring accurate adhesive placement, brushing often delivers the most consistent coverage.

Overall, brushing and dipping offer near 100% transfer efficiency, resulting in much less waste per gallon than spraying.

6. Substrate surface prepping

Once you are ready to apply the adhesive, make sure you complete the necessary surface preparation. Poor surface preparation is one of the leading causes of rubber to substrate bond failures.

Start by thoroughly cleaning and preparing the substrate so nothing interferes with the adhesion. Oils, solvents, rust, and even dust can act as barriers between the adhesive and surface, preventing a strong bond from forming.

Keep in mind that buildup is not only an issue before prepping, but also during the preparation process. If you’re not careful, you could easily re-contaminate the surface during the cleaning process.

For example, pressurized airlines often contain lubricating oil. If that air is used during the cleaning process, it can deposit oil back onto an otherwise clean substrate and negatively impact your bond.

This risk is especially high during grit blasting, where grit residue can stick to the oil left behind by the compressed air. Similarly, in caustic detergent baths, oil that isn’t fully removed can float to the surface and reattach to the substrate — potentially leading to a weaker bond.

To avoid contamination, make sure your oil-removing mechanisms and machinery are functioning properly.

7. Properly store and handle treated substances

Contamination doesn’t just happen during cleaning.  It can also occur after the substrate has been treated.  Proper storage and handling are just as important once surface preparation is complete.  For example, if you wait too long after a surface treatment like phosphating, the surface may start to rust.

Also, keep substrates away from potential sources of contamination, such as dust, oil, or moisture, between treatment and adhesive application.  Even small exposures can reduce bond quality.

If you use a sealant, make sure that it is compatible with the rubber to substrate bonding adhesives. An incompatible sealant can create a barrier layer between the substrate and the adhesive, weakening bond quality. In some cases, the sealant may need to be removed before the substrate is ready for bonding.

8. Creating the rubber to substrate bond

Now you’re ready to create the bond. Once the adhesive has been properly applied and dried, the rubber is introduced and cured. Avoid excessive pre-bake times to prevent the adhesive from curing too soon. Pre-bake time depends on the specific adhesive.

For instance, DuPont’s Thixon 560™ is resistant to longer prebake times while still enabling a reliable rubber-to-substrate bond. Checking the quality of the bond after molding helps you validate whether the bond meets required standards.

For more help with choosing, applying and evaluating DuPont rubber to substrate bonding adhesives, contact an H.M. Royal expert today. Our material specialists can answer your technical questions and ensure your bonding process delivers consistent, high-quality results.

Our entire team is dedicated to offering the highest level of expertise and customer service. We actively participate in the rubber industry’s leading organizations and events to ensure we offer the best solutions for your needs.