What is Silicone Sealant?

Silicone sealant in a caulk gun.
Applying silicone sealant to a wall.
Applying silicone sealant.
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  • Written By: Katharine Swan
  • Edited By: Niki Foster
  • Last Modified Date: 14 November 2015
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Silicone sealant or adhesive is a powerful, flexible product that can be used in many different applications. Although it is not as strong as some other sealants or adhesives, silicone remains very flexible, even once it has fully dried or cured. This type of sealant can also withstand very high temperatures, making it ideal for applications that suffer high heat exposure, such as on engine gaskets. It also comes in a variety of forms.

One way to buy silicone sealant is in a two-component addition; this type of product requires the user to mix two compounds to make the sealant. The mixture must be made immediately before using it, which makes it rather tricky to use. It's also available as a single product, with no mixing required. One type is called Room Temperature Vulcanizing (RTV), which starts to cure as soon as it is exposed to the air — or, more precisely, the moisture in the air. Because of this, it must be used quickly.

There are a variety of other, more technologically advanced forms of silicone sealant as well. One type, called pressure sensitive sealant, has a permanent tackiness and adheres with deliberate pressure. In other words, although it will always be “sticky,” it won’t stick if something simply brushes or rests up against it. Another type is called UV or radiation cured sealant, and it requires ultraviolet light to cure it. Thermoset silicone sealant requires exposure to heat in order to cure.


There are a variety of applications for silicone sealant. This type of sealant is frequently used in automotive and related applications, such as an aid for sealing an engine, with or without gaskets. Because of its superior flexibility, it is also a good choice for many hobbies or crafts.


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Discuss this Article

Post 41

A couple of answers to all the questions here:

@KipMom: Silicone isn't good for a mug. It's better to find glues suited to ceramic and glass repair and then ideally don't use the mug (I wouldn't trust glues with hot liquids in them anyway). Same would be suggested for coffee filter guy: there are different kinds of plastics and your basket is more likely a plastic not a silicone (ABS - plumbing style plastic - has glues but your filter is likely not ABS...)

Sunroof/windows: Yes, this is what silicone is commonly used for, google for how to repair leaking windows.

Aquarium: Google for fish aquarium forums as there is discussion there on what is compatible.

Silicone adheres only to silicone but

use the same type. In your household repair sections there is a type 1 silicone (you'll smell more vinegar, and can peel off the paint if it is not securely installed). There is also a type 2 silicone (still vinegary smelling but less likely to peel off paint, not a problem if you're applying to metal/glass, etc.). Mixed types: these mix latex into the silicone. Often used for bathroom sealing and are paintable, too. If adhering silicone to silicone try to stick with the same type (I, II or mix).

Silicone is not conductive, so using it on wire should be fine.

Silicone ingestion effects would suggest you have a specific silicone in mind so google for a MSDS sheet, maybe go to Dow's site.

Post 39

Can I use an aquarium sealant for replacing the caulk between the bathtub and tile, bath and floor tile, seal between top of sink and wall. I want something as non-toxic as possible. Thanks!

Post 36

Can silicone withstand high air pressures such as 60-120 psi?

Post 35

You can use acetone.

Post 34

What is the pH (acidity) for the silicone glass sealant? Is it corrosive to the metal?

Post 32

What are all the areas where this RTV silicone sealant is used?

Post 31

I am interested in buying silicoen sealent in bulk and market in my own name? Is it possible to do so? what are all the formalities should I undergo? or tell me steps to do so.

Post 30

can a silicone sealant resist petrol?

Post 27

Where do we buy the sealex's silicone sealant? Is Sx-2000 using for?

Post 25

we have leakages through the rubber beading of aluminum windows where the glass and rubber beading joins. please give a solution.

Post 24

how can i produce silicone sealant?

Post 23

which sealant do you recommend to joint silicone rubber to silicone rubber?

Post 22

How can I remove silicon sealant in between clear glass?

Post 21

Can I use silicone sealant on a freshwater aquarium?

Post 20

Can I use silicone sealant to seal up a head on a tecumseh minibike engine? Thanks.

Post 18

I have a leak in the sunroof and would this do the job to stop the water that leaks in?

Post 17

can i use silicone sealant to clad bath room walls in glass. what will be the life of it?

Post 16

Can I use acid cure silicone on a freshwater aquarium?

Post 14

Can I use silicone sealant to install the waste in an acrylic shower base and if so what procedure should I follow such as bead thickness.

Post 13

How long before RTV silicone sealant will start to break down when used outdoors?

Post 12

Can silicone sealant be used on electrical wires (bare or sheathed)?

Post 11

can i use a silicone sealant to fill a crack in my toilet cistern?

Post 10

Could you please give the presentation of Silicone sealant products which are used for building construction like glass & aluminum. industries. (What are the materials used? how many types of sealant etc..etc...)

Post 9

how can i produce silicon sealant?

Post 7

Can it be used to seal wood shingles?

Is there a liqude form that I can spray on?

Post 6

Please tell me what is the difference between neutral cure and acetic cure silicone?

Post 5

is it dangerous to ingest? if so what reactions could occur?

P.S don't worry no one here has ingested this product im just doing a project;-P

Post 4

Can this sealant be used to seal a crack in the basket that holds the coffee grounds of my coffee maker?

Post 3

Does RTV 382 have any reaction with diesel fuel?

If not what other sealant can be used?

Post 2

Would silicone glue allow me to repair a mug, broken in many pieces, so that it could be used again? My daughter's precious (sentiment) mug broke, and she wants to try and fix it. Would it be safe to use? Any special care once fixed? There will be cracks to fill as well as surfaces to join.


Post 1

How can I safely remove Room Temperature Vulcanizing (RTV) Silicone Sealant deployed by an ignorant customer to the Parallel Port of an Intel Motherboard supposedly to block the port?

What material can I use safely to clean the interior of the port from this sealant?


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