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What is Glass Sealant?

J. Airman
J. Airman

Glass sealant is a silicone-based liquid, gel, or foam product that is applied to glass surfaces in order to fill microscopic pores and create an anti-static, anti-fog, and high-gloss shield. Glass sealant is designed to adhere to the smooth glass exterior without the use of abrasion or primer. Once the sealant is applied to the glass, it begins to settle to a thin, even layer until it eventually dries to a transparent finish. When the glass sealant has completely dried, it forms a moisture barrier that causes water to bead up and run off without leaving residue behind. Many commercial glass cleaning products incorporate a sealant to protect the glass and make the surface much easier to clean and dry.

Protecting a glass sheet with sealant can usually be done in just a few minutes. The glass surface needs to be thoroughly cleaned first to increase adhesion. Most glass sealants are sprayed or wiped on to one or both sides of the glass with a soft cloth. Glass sealant does not effectively repair cracks and scratches in glass, although it may slow the progression of some glass damage. Sealing glass in a layer of silicone increases insulation to reduce the passage of heat or cold through the glass.

Silicone glass sealant in a caulk gun.
Silicone glass sealant in a caulk gun.

A variety of glass sealant products are available to coat car windshields and glass shower doors that often come in contact with moisture. Silicone-based sealant bonds to the glass to make a new surface that is slicker than ever before and resists fogging. Falling rain is quickly blown off sealed windshield glass to provide clear visibility for a driver without the need to use windshield wipers. Keeping a glass shower door dry between uses greatly reduces the amount of mineral deposits and lime scale. A shower door that has a layer of glass sealant does not fog up and dries off quickly as the walls roll off.

Glass sealant may be applied to panes before installation, or added to existing windows.
Glass sealant may be applied to panes before installation, or added to existing windows.

When glass that was once covered in sealant begins to lose its ability to repel moisture, it is probably time to apply a new layer of the product. Consult the label on each individual glass sealant product for suggested reapplication time frames and methods. Keeping a constant layer of protection in place usually reduces damage caused by exterior conditions and extends the life of the glass. The small investment in glass sealant frequently saves much more time and money than it takes to keep up.

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Discussion Comments


Our home used to get really cold in the wintertime and we had outrageous heating bills because of the temperature our rooms could drop to. We tried using door snakes to keep drafts out and sealing our windows with plastic bags, but it really didn't do the trick.

After a lot of inexpensive tricks we finally figured out that glass sealant was by far the best way to go. It works as an amazing insulator when applied correctly.

We have a friend who owns a window shop in town and he came over and showed us how to apply the sealant to our windows and the results were impressive. Our place was much easier to heat and our bills went down. Glass sealant is definitely a good investment.


We used to have a lot of trouble with our bathroom mirrors fogging up after showers which made getting ready for the rest of the day a real pain. We tried the old shaving cream rinse on the mirror trick, but found it only helped our problem temporarily.

A friend of ours suggested glass sealant and it really turned out to be a simple solution to an ongoing problem. Glass sealant can be picked up cheaply at most home improvement stores and it really easy to apply.

We found the version be bought kept the glass fog at bay and our windows actually dried faster when they did get water on them. We can now get ready each day without having to wipe steam off the mirrors or without having to wait 15 minutes for the bathroom to get clear of fog.


@amysamp - This is *not* one of those things I would personally suggest turning into a DIY (do-it-yourself) project. I have many handy friends but I have yet to hear of any of them to try fixing a dinged windshield!

But my main reason for saying do not do it yourself is that windshield repair can be completely convenient and free (in my state most insurance companies pay for fixing the ding as part of their policy because they would rather pay for that simple fix than replacing the entire windshield later).

It is convenient because there are companies that will actually drive to where your car is and fix it there! No having to leave your car at the repair shop and find a ride.


I had one of those small dings in my windshield and rather than having to spend a hundred dollars or so I thought I would try to make it a little do-it-yourself project.

Has anyone tried to do this? It doesn't seem like the glass sealant in this article would be the right stuff, but I wasn't sure what would seal that type of glass issue.

I am trying to get to it before the small ding turns into a serious crack!

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    • Silicone glass sealant in a caulk gun.
      Silicone glass sealant in a caulk gun.
    • Glass sealant may be applied to panes before installation, or added to existing windows.
      By: Bruno T
      Glass sealant may be applied to panes before installation, or added to existing windows.