To glue silicone to silicone, you will need the following tools and materials:

• Sandpaper 
• Silicone glue 
• Adhesive promoter
• Adhesive activator/ accelerator
• A hair dryer or a heat gun

When it comes to gluing silicone to silicone, many run into this seemingly complicated puzzle where the puzzle pieces are very complex and almost impossible to figure out.

This may be because there is much confusion or misunderstanding about what silicone is. If we don’t know what silicone is, how can we know which glue will work for it?

So keep reading to find out what silicone is and how you can glue silicone to silicone effectively and effortlessly.

Also, check out my guide on gluing puzzle pieces together for more tips.

What Is Silicone?

Some believe silicone is rubber, while others that it is plastic. But what is the factual truth when it comes to silicone?

Silicone does have properties of both plastic and rubber. But technically, silicone is rubber with elastic characteristics. 

Silicones are human-made viscoelastic, meaning it has viscose and elastic traits. These characteristics are what define a rubber. 

So now that we know that silicone is rubber and not plastic, we know what type of glue we need to be able to glue silicone to silicone. 

To start this project, make sure you have all the necessary tools and products, which are:

1. The sandpaper 
2. Silicone adhesive 
3. Adhesive promoter
4. Adhesive activator and accelerator 
5. A hair dryer or a heat gun

Since you will work with strong adhesives and materials, use protective gloves throughout this process. 

Step One: Sand the silicone

If you know silicone, you know that its surface is very smooth. Smooth surfaces are hard to glue together because the adhesive needs to be able to have an abrasion it can hold onto to form a strong bond. 

Use sandpaper to roughen the surfaces of the silicones you will be gluing together – each surface. 

This will create a rougher surface, ideal for a strong glue to hold the two surfaces together. 

Step Two: Clean each surface

Using sandpaper on silicone can leave residues on the surface. If you don’t clean the surface after sanding, this can prevent the adhesive from bonding effectively. 

Use warm soapy water to clean each surface. 

Using a clean cloth, you can also use a solvent, such as rubbing alcohol, or a cleaner to clean the surfaces. 

Before moving on to the next step, wait for the silicone surface to dry fully. 

Step Three: Apply the adhesive promoter

The adhesive promoter is a key product to use at this stage. This will help improve the strength of the bond once you glue the two surfaces together. 

Apply the adhesive promoter on each surface you will be gluing together. 

Step Four: Apply the activator/ accelerator

Usually, the adhesive activator and accelerator product comes in a spray bottle. 

1. Spray a layer of the activator/ accelerator over the surface of the silicone that will be glued together
2. Spray this product over one silicone surface and not both that will be glued together

This product will cause a stronger bond while speeding up the curing time. 

Step Five: Use a hair dryer or heat gun to warm up the surfaces

Use a hair dryer or a heat gun to warm up all silicone surfaces that will be glued together. 

Once the surfaces are warm (make sure they don’t become hot), you can turn off the hair dryer or heat gun and move on to the next step. 

Step Six: Apply the silicone adhesive

For this step, you will need one of the following:

• Silicone glue
• Silicone caulk 

Here is what you need to do:

1. Apply the silicone glue or silicone caulk to the surface of the silicone that does NOT have the activator/ accelerator agent applied to it
2. Connect the two silicone surfaces while applying some pressure 
3. Keep applying pressure for about 15-20 minutes – you can do this with your hands or using tools such as clamps to hold the silicones together. 
4. If necessary, apply silicone glue or caulk across the seam of the two silicones glued together.
5. Also, apply the activator/ accelerator on the seam to cause a tighter bond for long-lasting effectiveness.

Even if the silicone glue can dry after 15-20 minutes, the curing time will take much longer. 

Use clamps or other tools to secure your silicones in place for 24 hours. This will ensure a long-lasting tight bond.

Conclusion

Gluing silicone is not as complicated as you may have thought. The whole process takes only six steps, which are:

1. Sanding the silicone 
2. Cleaning the surfaces after sanding 
3. Applying the adhesive promoter
4. Applying the activator/ accelerator agent
5. Warming up the surfaces with a hair dryer or a heat gun
6. Applying the silicone glue or silicone caulk

In some cases, you may need to apply silicone glue and an activator/accelerator on the seam of the two silicones to strengthen the glue’s bond and tightness. 

For best results, during the drying time, apply constant pressure, pressing the two surfaces together. 

Don’t just wait for the drying time to be up. Wait 24 hours for the adhesive to fully bond the two silicone surfaces.