What Does Silicone Not Stick to? Applying Silicone Correctly

Usually, silicone does not stick to any material, and not all materials can stick to it. So, what does silicone not adhere to?

In this post, we will examine the few materials silicone will not stick to, including acrylic, polyurethane caulk, paint, and epoxy resin. Also, we will discuss the best way to apply silicone to get the best results.

What is Silicone?

Silicone is a hybrid of organic and silicone chemistry. It’s a combination of synthetic rubber and plastic polymer. Silicone sealant is versatile and popularly used in many do-it-yourself projects, including waterproofing and sealing. Silicone creates a solid yet flexible watertight seal between surfaces. Also, silicone is used in making kitchenware, among other products, since it’s safe.

Why Does Silicone Not Stick to Anything?

When you’re working with silicone, you have to know that silicone by itself doesn’t stick to anything. Silicone is a polymer-based adhesive that adheres to the substrate via a pressure-sensitive adhesive (PSA) system. Therefore, if you apply silicone adhesive on something like metal or wood without applying pressure, it won’t stick directly to the material, and you’ll have a bunch of messy silicone all over the place.

For silicone to stick to something, you always have to make sure you use PSA. That means if you apply the silicone to a surface and then apply pressure, the silicone will bond to the surface.

What Does Silicone Not Stick to?

Although silicone is an excellent sealer and a versatile product with many uses, you need to know what materials silicone does not stick to. Here are materials silicone cannot stick to:

1) Acrylic

Silicone adhesive does not adhere well to acrylic. Silicone sealant cannot bond with acrylic sealant. They have two different kinds of properties. While acrylic is a polymer, silicone combines both organic and silicone chemistry. Commonly, silicone sealant has many advantages over acrylic adhesive; hence silicone is popularly used. However, if you want to paint over the adhesive you have used, then you should use acrylic sealant.

Mainly, acrylic is a different type of plastic than silicone adhesives that do not share the same properties. For example, silicone is usually very flexible and durable, but acrylic durability and rigidity highly depend on the climate. Therefore, since the two products are different and you cannot use one over the other, you can choose to use one at a time. If you want to change the sealant you have used for the other, you need to remove the old one and apply the new one.

2) Some Polyurethane

Polyurethane caulk does not adhere properly to standard silicone. People who attempt to use polyurethane caulk on silicone run into problems since the two materials cannot form a strong bond between them. Polyurethane caulk and silicone caulk have different properties. For instance, while silicone caulk is inorganic and flexible, polyurethane is organic and rigid. If you try to use polyurethane caulk on silicone, the caulk will not adhere properly.

But, their different forms of these caulks can adhere to each other. If you really want to use one over the other, you need to verify the type of polyurethane and silicone you have before attempting to use them together. Alternatively, to fix the problem of not correctly adhering to each other, remove the silicone and put the polyurethane caulk on.

3) Epoxy Resin

Epoxy resin does not adhere to silicone. Although it seems a negative characteristic, you can use it to your advantage during your DIY project. You can conveniently make and use silicone molds when you want to work with epoxy resin for your artwork. You can make small items such as jewelry without the epoxy resin sticking to the silicone molds.

4) Paint

Although silicone caulk can adhere to painted surfaces, paint cannot adhere to silicone caulk. Therefore, if you want to silicone caulk a surface and paint, you should paint first and then seal. Alternatively, use a paintable caulk instead of silicone if you must paint over the sealant.

What Materials Does Silicone Stick to?

Silicone is a fantastic product that can be used to bond and seal all sorts of things. Typically, uncured silicone can stick to most surfaces such as:

  • Silicone sticks to plastic, and it’s used as a suitable sealant between two plastic surfaces.
  • Glass is one of the popular products on which you can use silicone sealant. The silicone bonds well to glass surfaces.
  • Silicone adheres well to the metal surface.
  • Silicone rubber. Silicone adhesives stick well to silicone rubber. Notably, to stick to silicone rubber, you must ensure the silicone rubber surface is very clean, free from dust, loose particles, and dry.
  • You can quickly seal a leaky PVC pipe using silicone. Notably, ensure the pipe is dry before applying the sealant bonds well.

Benefits of Silicone

Here are the benefits of using silicone for sealing gaps or cracks and bonding surfaces:

  • It’s safe and durable
  • Low maintenance
  • Easy to apply using a caulking gun or equivalent applicator
  • Least sensitive to temperature
  • Non-permeable
  • Non-reactive resistant to chemicals
  • Malleable and flexible
  • Versatile
  • Available in various colors to match the bonded material
  • High-gas permeable
  • Available in various formulations to suit different needs
  • Easy to clean
  • Non-stick and non-staining

Silicone Uses

The popular uses for silicone include weatherproofing, sealing gaps and cracks, and creating a watertight seal. Silicone is mainly so popular because it has many benefits and good properties. Silicone is perfect for sealing up cracks and leaks in one’s home. It can seal up many areas, including around bathtubs and sinks, windows, and even along the grout lines in your bathroom or kitchen.

Also, silicone seals can be used for outdoors caulking to keep out rain and moisture. Due to the material’s durability, it is a top choice when sealing around swimming pools and in places where excess water will be present.

How to Apply the Silicone Correctly?

When applying silicone, you should ensure you do it so well such that it’s tidy, well used to serve its purpose and it’s appealing. If you’re looking for basic instructions on how to apply silicone sealant, please read the manufacturer’s instructions.

The following are easy-to-follow steps for a simple DIY project:

  1. Choose a suitable silicone sealant. Before you decide on the suitable silicone sealant to use, check the materials you want to use silicone on. There are various silicone products, each having specific properties.
  2. Prepare the surface. Scrape and brush the surface to remove all unwanted residue. Scrape any dirt and residue from the surface you want to apply silicone. Silicone will not adhere well to the surface if it’s dusty and has loose unwanted residue. You can use a scraper or a knife, a brush, and a paper towel.
  3. Cut the silicone can nozzle.To cut the nozzle, lay the can flat on a hard surface and cut it using a window scraper or knife. Ensure the hole is sufficient. Importantly, if you don’t have a silicone gun or cannot use the silicon tube because it’s damaged, you can put the silicone into an alternative container, such as a plastic bag or cake decorating bag.
  4. Put the silicone tube into the gun. The caulking gun is convenient to use; hence you need it. Put and position the sealant tube correctly inside the gun. Ensure the tip sticks out at the opposite end of the release and press the gun tab.
  5. Test to see whether silicone flows at the required pace. For a neat job, you need to have a hole of the right size for steady flow. After testing, if you are unsatisfied with the flow, you can slightly widen the hole until you get a proper flow.
  6. Run the masking tape along the length you want to apply the silicone sealant.For a neat, straight line when applying silicone, use masking tape. Leave an 8mm gap between the masking tape strip.
  7. Apply the silicone.Drag the silicone sealant can move along the seam surface. While applying, don’t worry much about the mess, but ensure you are applying a sufficient amount along the seam to seal the gap.
  8. Neaten the sealant.Using a finger, neaten the adhesive and wipe off the excess adhesive. To prevent the silicone from sticking to your finger, dip the finger into the white spirit. Importantly, if you don’t have the white spirit, you can use water and wash soap to ensure your finger is slippery. Then press the finger smoothly and evenly along the length you have applied the sealant.
  9. Remove the tape. Once you apply and neaten the sealant, peel the tape away.
  10. Allow the silicone to dry. The silicone sealant should fully cure in 24 hours. Notably, for the silicone to cure faster, you can use the fast-drying silicone, which takes only 30 minutes to cure. Alternatively, use a little heat and blow air to fasten the drying process.


Apart from a few materials silicone does not stick to, silicone adheres to various materials, as you have learned above. Therefore, if you’re looking for a material to use on multiple projects, silicone sealant or caulk is a great option. You only need to know which material it can stick or not and how to apply it correctly.