Can you use silicone as glue?

Silicone is a very popular sealant in multiple industries. But a common question that pops up is; “can you use silicone as glue to bond materials in place?”

The simple answer is yes, you can use silicone as glue. But you will need to consider how strong you want the bond to be and how much you want to spend on a high-quality silicone before using it to seal and bond.

Here at Forgeway, we manufacture tonnes of adhesives and sealants every year. Even though we do not manufacture silicone sealants, we are experts in the adhesive and sealant industry. We know that you can use silicone as glue. However, there are a few things you need to be aware of first. 

In this article, we will go over what you need to know before using silicone to bond as well as seal. By the end of the article, you will know the best way to seal and bond at the lowest price.

Why you might need to use silicone as a glue

When using the phrase ‘silicone’ you will likely be referring to sealant. This is because silicone is the main sealant that is known and used. Silicone is a term used to describe a type of sealant, whereas sealant is a type of adhesive used specifically to keep something airtight or watertight. 

So where might you need the sealant to not only seal but provide a strong bond too? 

This situation is a lot more common than you might think. We have listed some examples of where sealant is used to bond as well as seal.

  • Sealing and bonding glazing into position.
  • Sealing and bonding wall panels on the interior of yachts.
  • Sealing and bonding the rubbing band on the exterior of yachts.
Applying sealant to a vehicle
A sealant holding glazing in place

As you can tell, when the sealant also has high strength, it allows you to use the sealant to hold the substrate(s) in place too.

Can silicone provide a strong bond?

The answer to this question is always going to be ‘it depends’. Because there are so many grades of silicone, it is impossible to say that all silicone will be strong enough to form a strong bond. So it depends on the grade of silicone.

But it also depends on what you define ‘strong’ as. ‘Strong’ is very subjective. Our version of ‘strong’ may differ from what you would define as ‘strong’. However, for the purpose of this article, we will say that a strength of more than 1Mpa is strong. 

So can you get strong silicone? Yes, some grades of silicone are strong enough to form a strong bond. In fact, some grades of silicone can reach strengths of 2Mpa. 

Unfortunately, due to the competitive nature of the sealant market and supply chain issues, most silicones are heavily diluted. You will have to cough up a considerable sum in order to find a silicone sealant that is made from 100% silicone. However, if you want a strong silicone, a 100% silicone sealant will be strong enough.

Silicone prices are shooting up; But why?

Your typical silicone will have a tensile strength of 0.5Mpa. And whilst this strength is still by no means ‘weak’, it is the flexibility of these low-grade silicones that causes problems. They are so flexible that the silicone itself will stretch when put under too much strain.

Or, a specially formulated silicone sealant would also be strong enough to form a bond. Particular examples of these specially formulated sealants are for structural glazing situations.

Ultimately, you will be able to find a silicone that is strong enough to form a bond. However, a stronger silicone will cost you more money.

Should you use silicone as glue as well as a sealant?

So whilst you can, we would never recommend using silicone for bonding. And the main reason for this is because there are so many sealant options. These options will enable you to find a cheaper sealant that has higher strength.

Spending more money to get a high-strength, high-grade silicone is not the only way to get a sealant that can form a strong bond. Instead, we would always recommend using an MS polymer sealant when looking for a sealant with high strength

Unless you are prepared to pay the extra money to get a silicone with high strength, an MS polymer sealant will be a much more cost-effective option. 

This is because even the lower-grade MS polymer sealants will have the same strength as the high-grade silicone sealants. There are a few other benefits to using an MS polymer sealant too. We wrote an article that weighs up MS polymer vs silicone sealants.

However, the other main advantage to using MS polymer sealants is the ability to paint over them. 

A lot of automotive and transportation manufacturers have banned the use of silicone in their manufacturing facilities. The reason for this is that silicone is an invasive contaminant. When there is silicone on the surface, the silicone will attack the paint causing dimples and imperfections in the paint’s finish.

Overpaint silicone
If you paint over silicone, it will leave an imperfect finish

Can you justify spending more on a higher-strength silicone?

Unfortunately, we cannot answer this question for you. Whilst there are many different factors you need to consider before choosing a sealant, we would say that you should consider using an MS polymer sealant instead of paying more for a high-strength silicone.

As adhesive specialists here at Forgeway, we understand how difficult it can be to choose the best sealant for you. 

If you want a sealant with high strength that will not cost you significantly more than traditional silicone, we would say that MS polymer sealants are the option for you. Our blog on MS polymers will give you an overview of what they are and why they might be a good fit for you.

Alternatively, if you like using silicone because of how easy it is to use, and you don’t mind paying extra for the higher strength, then it is a no-brainer. 

However, you may still be unsure about what the best sealant is for you. A member of our team will be able to help you decide for your specific situation.

Or you can download our comparison chart of sealants to determine which one would be best for you.