Acrylic or Silicone - What Do I Need?

Both silicone and acrylic are sealants used in home and craftwork for sealing joints. Silicone can be used both indoors and outdoors, while acrylic is primarily used indoors. Both sealants aim for the same goal but have different properties. To choose the right product, it is necessary to understand these, sometimes very important, differences.

The Properties of Silicone

Silicone is a very elastic sealant and resembles a rubber cord once cured.
Silicone is a water-repellent sealant. This property is also known as hydrophobic.
Silicone usually contains additives that prevent mold growth.
The sealant has good resistance to acids, electricity, and heat.
Silicone takes a longer time to cure.

The Properties of Acrylic

Acrylic is rather inelastic and tends to crack with too much movement.
Acrylic is a hydrophilic sealant, meaning acrylic is water-permeable.
Acrylic does not have mold-resistant properties.
Once cured, acrylic can be painted over.

When to Use Acrylic and When to Use Silicone?

As mentioned in the introduction, it depends on the specific application area.

Silicone is recommended for expansion joints between two materials that exhibit a high degree of movement. This includes materials like wood. Wood is a very "working" material that expands or contracts depending on the temperature. Silicone should also be used wherever there are recurring vibrations or temperature differences. It should also be used in wet rooms, such as bathrooms, kitchens, laundry rooms, and utility rooms.

Also, consider the subtle differences within the silicone family. By adjusting the ingredients, manufacturers further tailor their products. Some properties are thus enhanced. Examples include the following areas:

Bathroom and sanitary
Window connection joint
Kitchen construction

Acrylic, on the other hand, should be used for joints that do not require high flexibility or vibration. It is relatively cheaper and thus closes these joints cost-effectively. The sealant can also be painted (wait for curing time!) or wallpapered. This is even recommended to prevent dirt from accumulating in the pores of the acrylic.

Possible areas of application include:

Repairing settlement cracks in masonry
Connection joint of interior doors
Sealing joints between plasterboards

Summary and Final Tips

As can be seen from the guide, acrylic and silicone are products with the same goal: sealing joints. However, attention should be paid to the properties of the joint to be sealed and the room. Silicone has some properties that protect against environmental influences but cannot be painted over. Acrylic, on the other hand, can be painted and is generally cheaper. The lack of properties against environmental influences and inflexibility greatly limit its application range.

No matter which sealant you choose, please consider the following tips:

Completely remove the old sealant. This can be aided by:
- Cold: Using temperatures below 0 degrees will cause the sealant to lose its flexibility and be easier to remove.
- Acetone: The extremely aggressive composition of the solvent will destroy the adhesion of the silicone. Please test on an inconspicuous area first to avoid surface damage
- Silicone remover: Use specific silicone removers that are optimally suited for this task.
Clean the joint before sealing.
Wear gloves during processing.
Thoroughly clean your hands after completing the task. Silicone is particularly dangerous for the eyes and respiratory system.