Sealants Overview

Sealants are used to provide a barrier between all different sizes of spaces. They may be applied to a porous surface to prevent impregnation with water or other environmental contaminants. They may be applied to the junction of a fixture and the structure of a home, preventing a barrier to water flowing into the non-waterproof areas of the home, such as in the case of bathroom caulking. They may be used to seal very large cavities, such as sealants that are injected into a cavity and then expand to fill it completely, or almost completely.

Sealants play a significant role in not only protection, but in efficiency. The energy efficiency of a building is significantly impacted by how well the outside and inside environments are separated and, at doors, windows and in areas where pipes and conduits pass through walls, sealants provide that separation.

Sealants are very similar to adhesives in many regards, but are not used to provide a strong bond between separate surfaces or objects. Their adhesive properties keep them in place, but it is the barrier that they maintain that makes them useful.

Sealants generally take time to set into place, a process of hardening called curing, and they do not perform as expected if they are not allowed to cure. Some sealants are sold as binary chemicals that have to be mixed together before being used.


What Is Sealant Used For?

Sealants provide a barrier that resists the flow of gas, air, liquid or other substances. Some are more specialized, such as firestop putties, which are designed to prevent fire from moving from one area to another through openings in walls.

Sealants are used to provide this barrier protection on many different substances. Masonry, wood, ceramics and metals, as well as other materials, have sealants that work with them. Some sealants, such as silicon sealants are useable with many different materials.

Sealants can have more or less adhesive properties, which affects the uses to which they can be put. They also come in the forms of liquids, semi-solids, foams and more, allowing them to be used in many different capacities. Some sealants are two-part chemicals, which have to be mixed before the sealant is put in place.

The main function of a sealant is to fill a gap. It adheres to the surfaces that create the gap and provides a barrier between them.


What Is Considered the Cure of a Sealant?

When a sealant is put in place, it goes through a process called curing. This is simply the process of the sealant hardening into its final form. If the sealant is not allowed to cure properly, it will not function as intended and may well fail to provide a barrier.

Most sealants are sold with the cure clearly listed. This is the amount of time that the sealant takes to cure at a given temperature, usually room temperature. Higher or lower temperatures may increase or decrease the curing time.

Curing can be sped up by providing airflow—such as with a fan—or by adding other materials, in the case of some types of sealant. In most cases, however, the sealant is merely left in place for the designated amount of time. It can be tested in various ways. If the sealant is not harmful to touch, it can usually be depressed a small amount. If it doesn’t change shape, it’s dry. If it does, it is not fully cured yet.


What Are the Properties of Sealant?

A sealant can be described as having many different properties. The most important is usually the application, which dictates on what materials and under what conditions the sealant can be reliably used. Other properties include the time it take to cure, the form it comes in and the maximum and minimum temperatures the sealant can perform in.

Sealants are also described in terms of their adhesion. This is the strength with which they adhere to the materials to which they are applied. Greater adhesion is desirable in most cases, though some sealants are designed to provide minimal adhesive properties.

Sealants are also described in terms of their resistances. A sealant, for instance, may have a resistance to corrosion that makes it particularly desirable for specific applications, such as in plumbing. Some sealants designed for specific applications, such as those designed for shower and tub use, may have anti-mold properties that make them more desirable.

A sealant should not be soluble under the conditions in which it is being used. Sealants are frequently sold as being resistant to specific substances with which they may come into contact.

Sealants should not shrink a great deal after they’re applied. Ideally, they should fill any cavities and voids and retain very close to their initial shape when applied, allowing the sealant to provide a complete barrier.

A sealant also needs to last for a predictable amount of time under expected circumstances. Bathroom caulking, for instance, should hold up for a given amount of years before it degrades. The longer a sealant lasts the more desirable it is.



What Is the Difference Between Adhesives and Sealants?

Sealants are used to fill voids. Adhesives are used to fasten two objects together. Sealants, like adhesives, penetrate into very small cavities, but they are not particularly strong. They also elongate more than adhesives, providing a less secure bond.

Some sealants have higher adhesive properties than others do. Some adhesives are also employed in particular usages because of their sealant properties, which make them desirable in applications where two surfaces need to be fixed together, but where a barrier between them is equally important.


What Types of Sealants Exist?

Different types of sealants offer different degrees of chemical and environmental resistances, flexibility, temperature tolerances and other qualities.


Acrylic Sealants

Sealants are among the most common uses for acrylic materials. Acrylic materials are very durable and resistant to many common environmental threats. These are thermoplastic substances. The construction industry is a heavy user of these types of sealants.


Anti-Spatter Sprays

Anti-splatter spray is used in welding. It prevents the splatter generated during welding from adhering to exposed surfaces. This can help the welder to avoid very difficult cleanup and damage to surfaces nearby the area actually being welded.


Cement Sealants

These are used for fittings and grouting. They are designed to set fast and are used to affect repairs on cement surfaces. They may be used to fix cracks in concrete or, if a pipe needs to be run through concrete, they may be applied to prevent the environment in one room from leaking into the other.


Chemical Sealant Removers

Sealants are designed to be tough and, therefore, are hard to remove. These removers make the process easier. They come in formulas designed to remove cured and uncured sealants and in formulas designed for specific applications, such as removing gaskets.


Combined Adhesives and Sealants

Adhesives and sealants are closely related. They can be used to repair and seal off areas. They can be purchased in colors so they can match the areas that they’re being used to repair. They’re not as specialized as either sealants or adhesives, but provide a good mix of both properties.


Epoxy Putties

Epoxy putties usually come in a tub. They contain two parts, which must be mixed together to produce the sealant. Epoxy putties are usually designed for use on a specific material, such as ceramic or metals.

Putties are typically used to fill foods only, not for any adhesive properties. The putty form makes it easy to apply these sealants over a wide area, sealing off larger voids, such as those in the areas where pipes penetrate walls.


Firestop Putties

Firestop putties are used in areas where fire resistance ratings need to be improved. They prevent fire from moving from space to space. This can provide much greater control over the spread of fire through electrical conduits, joints and junctions and through other areas where fire may be able to move freely. These may be required to meet building codes in some situations.


Leak Sealers

Leak sealers are used to affect minor repairs on equipment. They usually consist of a two-part substance that is mixed together and applied at the site of the leak to seal it off. They can usually withstand and function in a wide range of temperatures. Leak detectors may be used in conjunction with them. They are sometimes formatted so that they can be applied to areas that are wet, allowing them to be used on lines that are presently leaking and need a fast seal. They are also sold as ways to seal off leaks in windows or other areas where airflow may need to be controlled.


Pipe and Thread Sealants

Pipe and threat sealant provides a barrier against leaks at the threaded junctions of pipes. These are very common types of sealants, being used at most any threaded junction of two pipes. These sealants come in solid forms, pastes, liquids, gels and in a tape form, which offers very easy application.

These sealants can prevent a great deal of waste by stopping water from leaking out of the threads of pipes. They can also prevent damage in this way, by preventing pipes from leaking behind walls and under floors, destroying wood and other materials.


Pipe Sealing Cord

This is pipe sealant provided in cord form, offering a different method of application. It can be used in place of PTFE tape, commonly called plumber’s tape, as well.


Plumbers Putties

Plumbers putties are usually made out of two materials that are combined into one substance. It offers controllable applications and protection against corrosion and ageing. Some of these materials are non-toxic. These materials are not usually used for their adhesive properties, but simply to fill a void.


Polyurethane Foam and Sealants

Polyurethane foam and sealants can be sprayed into areas that are hard to reach. It can expand to fill cracks and other areas, making it an effective solution for sealing windows, doors and other areas. It can also be used on vehicles.

This foam can expand a great deal after it is sprayed in place, making it ideal for filling some larger cavities. It is also inexpensive and easy to apply. It can be purchased in spray cans that are disposable and easy to keep clean.


Retaining Compounds

Retaining compounds are used to provide adhesion for bearings, seals and for other purposes. These compounds fight against corrosion, as well, by protecting parts against leakage. These materials are sometimes manufactured so that the parts bonded with them can be freed easily, allowing for cleaning and replacement.


Sealant Kits

Sealant kits are designed to provide enough sealant to complete a job with no waste. They can include many different types of sealants, such as silicone or acrylic sealants.


Silicone Sealants

Silicone sealants are used in a wide variety of applications. They are used to seal electrical parts, doors and windows, refrigerators, masonry and more.

Silicone sealants can be injected into very small spaces and expand and fill spaces as they dry. They have to cure and this is sometimes accomplished by exposing them to specific substances after they are put in place.

Silicone can endure extreme temperatures and exposure to a range of environmental threats without degrading. It has many desirable properties as a sealant. It can hold up to UV light exposure, ozone and other hazards that can destroy other materials.


Urethane Liquids and Putties

Urethane sealants are available in forms that are semi-solid and that are liquid at room temperature. They can be used to encapsulate parts, providing them with complete protection. Other types of urethane sealants are used in bathroom and kitchen applications. These sealants sometimes boast fast curing times, making them very convenient for repair work.

Urethane sealants also have the advantage of being very flexible, in many cases. This makes them well suited for applications where the void that they are sealing may change size, such as when a pipe expands when hot or contracts when cold. Polyurethane is frequently used in wood sealants in and other applications.