Introduction

There’s nothing more frustrating than a sealant that did not cure correctly AND cracked too soon, or just didn’t provide a finishing touch. Most the time, it is not the product that is bad, it is the storage, handling, and/or the application.

Dow sealants are trusty sealants, and along with sealant 791, is one of the most recognized sealants in the construction and glazing industry. However, even the best sealants perform poorly if they are not applied correctly. Whether you are sealing expansion joints, glazing curtain walls, or performing everyday routine construction, applying these products correctly will make a world of a difference regarding performance and longevity.

In this guide, I will show you the best and most efficient was of storing, handling, and applying BOW sealants along with real-life applications that you can start doing today. A product comparison and additional insights will also be in this guide to help you determine which of the Sika Sealants will best help you.

Why Proper Use of Dow Sealants Matters

At the end of the day, product performance is the most important. Dow sealants are high performing sealants, but if used the wrong way, it will underperform.

Here’s what proper usage ensures:

• A surface’s adhesion and bonding strength are maximized.
  
• Longer lifespan of joints and surfaces
  
• Cleaner, more professional finish
  
• Reduced risk of joint failure, leaks, or cracks
  
• Better value from every tube

Understanding the Different Types of Dow Sealants

Before we jump into best practices, it helps to know what you’re working with.

Dow 791 Silicone Sealant

Dow 791 is a neutral-cure silicone commonly used for:

• Glazing applications
  
• Weatherproofing
  
• Expansion and control joints
  
• Perimeter sealing
  

It’s known for its flexibility, UV resistance, and excellent adhesion on a wide range of substrates.

Other Dow Silicone Sealants

Depending on the job, you may also come across:

• Dow 795 – structural glazing
  
• Dow 776 – high-performance weatherproofing
  
• Dow 758 – neutral-cure, paintable
  

The difference of each product will include different curing rates, different handling and strength requirements. So, it is mandatory to check the data sheet of each product.

How About Sika Sealants?

Sealants from Sika are also another big name in construction. While Sika sealants are a great alternative, especially to polyurethane, they often are not the same concerning:

• Cure time
• Compatibility with substrates
• Weathering resistance

Proper Storage Tips for Dow Sealants

A primary method to avoid sealant malfunction is by ensuring you have proper storage of the product prior to unsealing it.

1. Keep sealants in a cool, dry place

Sealants should be stored in temperatures ranging from +5°C to +25°C.
Excessive heat can cause the cartridge to cure too early, whereas, sub zero temperatures can change sealant texture.

2. Avoid direct sunlight

UV exposure accelerates degradation and can affect the chemical stability of silicone.

3. Store cartridges standing upright

This stops sealant from sitting at the nozzle and eliminates the chances of trapped air.

4. Rotate stock regularly

A basic first-in, first-out strategy guarantees you are using the freshest stock.

5. Always check the expiry date

Using expired materials, particularly Dow 791 sealants, can lead to poor adhesion, cracking, and incomplete sealing.

Handling Dow Sealants the Right Way

Once you have formed proper storage of the product, the next step is to ensure you have formed proper habits. This ensures the sealant inside stays consistent and is unspoiled for use.

1. Bring sealants to room temperature before use

Cold cartridges would be harder to dispense and texture of sealant may not spread properly. Allow them to sit, rather than using a heat source.

2. Avoid puncturing or squeezing the cartridge before loading

This may let in air and result in uneven application.

3. Use the right tools

A high-quality caulking gun delivers:

• Smoother beads
  
• Better control
  
• Less hand fatigue

For Dow 791 and other neutral-cure silicones, a continuous, steady flow is key.

4. Cut the nozzle at the correct angle

A 45° angle gives you better contact with the substrate when sealing joints.

5. Always wear gloves

Not just for cleanliness—silicones can be difficult to remove from skin.

Application Tips for Perfect Results

Application is where you’ll see the biggest impact on performance. These tips are based on real-world experience from installers and glazing specialists.

1. Surface Preparation Is Everything

Before applying any Dow Sealant:

• Clean the surface – remove dust, moisture, oil, old sealant, and contaminants
  
• Ensure the surface is dry – moisture interferes with adhesion
  
• Use a compatible cleaner – Dow primer or alcohol wipes depending on the substrate

2. Use a Backer Rod Where Needed

For deep joints, using a backer rod helps:

• Control the depth of the seal
  
• Create the ideal “hourglass” shape for movement
  
• Prevent three-side adhesion
  

3. Apply with Steady, Consistent Pressure

Maintain a continuous bead with no breaks or air bubbles.
For best results:

• Move slowly and consistently
  
• Overfill the joint slightly
  
• Keep the gun angled correctly

4. Tool the Sealant Immediately

Within minutes of application:

• Smooth the joint
  
• Ensure proper adhesion to both sides
  
• Remove excess for a clean finish

Use a tooling spatula or your gloved finger lightly dipped in soapy water (if compatible with the sealant).

5. Allow Proper Curing Time

Curing varies by humidity, temperature, and product type.
Dow 791 typically cures at about:

• 3 mm per 24 hours (depending on conditions)
  

Avoid touching, painting, or exposing the joint to stress too early.

Common Mistakes to Avoid

Even experienced professionals slip up sometimes. Watch out for these:

• Applying sealant to wet or dusty surfaces
  
• Using expired cartridges
  
• Applying in extreme temperatures
  
• Forgetting the backer rod
  
• Using the wrong sealant for the substrate
  
• Not reading the technical data sheet (TDS)
  
• Applying too thin or too thick a bead

Sika vs Dow: Which One Should You Use?

Both Dow and Sika Sealants are excellent. Here’s the quick breakdown:

For glazing, curtain walling, and weatherproofing, Dow 791 is almost always the top choice.

For heavy-duty, high-strength bonding, Sika may be preferable.

Most professionals use both depending on the project.

Conclusion

Using Dow Sealants properly isn’t complicated—it just requires the right approach. When you store them correctly, handle them with care, and apply them using professional techniques, you get the performance these products are designed for: long-lasting, flexible, and reliable seals that stand the test of time.

Whether you’re working with Dow 791, other Dow silicone products, or comparing them with Sika Sealants, proper technique is what ensures a flawless finish.

If you’re sourcing high-quality sealants from a trusted supplier, you can explore the full range at Dortech Direct, where you’ll find Dow Sealants, expert support, and everything you need to complete the job with confidence.