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The nature of the Glass Staining.

Glass CorrosionDid you ever know that glass is not completely smooth. Under a microscope glass reveals a rougher surface made of peaks and potholes. Organic and inorganic contaminants often carried by water fill those potholes and react chemically with the glass, firmly bonding to its surface. As a result, glass easily becomes stained and discolored. 

When glass is new those potholes are so small that even settled contaminants are not visible. But overtime glass exposed to water or intensive mechanical cleaning becomes even more rough and potholes can accomodate much more deposits. That process of glass  deterioration is also called glass corrosion. To conclude, there are two factors affecting glass staining: glass corrosion and exposure of contaminants dissolved in water.


RayAccess, Inc. are experts in Glass Stains Removal. There are different types of stains that can appear on glass. Here are the most common:

a. Hard water stains 

b. Glass Oxidation

c. Chemical damage (as acid or alkali etching)


hard water stainsHard Water Stains are the most common type of glass damage. They can appear as grey or white hazy stains with shape of water drips.  Basically, Hard Water stains are result of glass corrosion due constant exposure by water and concentration of inorganic compounds dissolved in water (TDS). In regular water there are hundreds of different ions of dissolved materials, the most of them are calcium (Ca+2), chloride (Cl-), magnesium (Mg+2), sodium (Na+), sulfate (SO4-2).   Solids dissolved in water literally stuck in rough surface of the glass and react chemically bonding with the glass. The result of those chemical reactions are insoluble compounds that can be removed only mechanically or chemically.

The most common areas of Hard Water Stains are shower doors, windows located near irrigation sprinkler or areas of constant water dripping (for example, under the defected flashing or gutter joint). In rainy season water running down the building can also cause hard water stains carrying excessive amount of dissolved materials from stucco, concrete and so on.

Please see methods of Hard Water stains removal below.

How to avoid Hard Water staining

There are two ways to avoid Hard water stains appearance.

a. Stop glass corrosion by eliminating the water exposure if possible. For example, redirecting or improving irrigation system around a building.

b. Protect the glass from corrosion by applying sealer on the glass surface. Most of the glass sealers can provide 1-2 years protection depending on sun and water exposure, and then need to be reapplied. Important: often glass needs to be cleaned from Hard water stains before sealer application.


Glass OxidationGlass Oxidation occurs when metal screens or frames around windows are exposed to rain or humidity and deteriorate causing oxidation. These products of oxidation run down the windows and penetrates or cling with the glass. It's appeared as almost clear to grey hazy staining right below frames or metal elements on exterior of a building. 

Glass and Metal Protection with special sealers can significantly reduce probability of oxidation.




Agressive chemicals contained acid or alkali can significantly speed up cleaning procedures of the glass but the same time they can make even more damage. Those chemicals react actively not only with contaminants but also with the glass causing intensive glass corrosion with staining called etching. Etching goes much deeper in glass structure comparing with hard water stains and oxidation. Therefore, removal of etching requires deep glass restoration pretty similar with Glass Scratches Removal. Etching looks as hazy stain reflecting area of chemical application. 

In most cases chemical damage is happened during attempts to use acid or alkali to remove hard water stains, oxidation, construction contaminants or in routine cleaning. Frankly, acid or alkali solutions are acceptable on some type of clear tempered glass, but in most cases are not. At least preliminary test in hidden area should be implemented before using of agressive chemical.


In common classification there are 2 stages of severity of glass stains. Actually those stages are more about glass corrosion then stains. Because then deeper corrosion in the glass structure then more severe glass stain and then more difficult to restore glass to original clarity. Glass stain (corrosion) close to the surface is Stage 1, deeper in glass structure is Stage 2.

Next test can be applied to recognize stage of glass staining. Make stain area wet, if you still can see stain on a wet glass most likely this is Stage 2, if not it's Stage 1. 

Efficiency of stain removal process depends not only on depth of the corrosion but also on what kind of chemical reactions and bonds created between contaminant and glass. Therefore, even if it's Stage 1 corrosion, removal trial should be applied on small and the most exposed area to understand how efficient would be glass restoration.


There are two methods to remove glass staining and restore original clarity of glass.

chemical removalMethod 1: Chemical removal

Chemical removal is based on idea of dissolving contaminants and their bonds with glass by more agressive chemical reagent as acid or alkali.

Advantages: It is the fastest and less expensive way to remove Stage 1 staining.

Disadvantages: Chemical Removal is very risky with high probability to etch the glass and increase corrosion. Chemical removal works with certain types of clear glass and certain type of stain. After dissolution of contaminant deposits there is still the same corroded glass with deep potholes. So, glass must be protected with sealer. Otherwise, hard water stains or oxidation will reoccur in short time. Also, there is certain potential damage to environment by application of agressive chemicals. It can be hazardous for operator if he doesn't wear proper personal protective equipment.

Method 2: Glass Polishing

glass polishingGlass polishing allows to mechanically remove contaminants and flatten back glass surface.

Advantages: Glass Polishing works perfectly with any type of glass and the most of Stage 1 and 2 staining. The result is polished and flattened glass surface that significantly reduce possibility of stain reappearance. Glass polishing also can remove small glass imperfections and chemical etching.

Disadvantages: Glass Polishing is more time consuming and expensive then Chemical Removal. Restoration process requires application of special equipment like buffer with adjustable RPM, polishing pads and polishing compound, pads for corners and etc. Glass Polishing requires special skills and experience in glass restoration due possibility to scratch or mechanically damage the glass. Glass protection by sealer is also recommended. 

However, if glass corrosion is so deep that even Glass Polishing can not remove the stain. There is also Glass Abrasion method mostly utilized for scratches and glass imperfections removal by resurfacing the glass. See also  Glass Restoration for more information about Glass Abrasion.


RayAccess, Inc. specializes at glass restoration and stains removal. Our experience and equipment allow us to achieve great results with reasonable price. We work with any size of project from apartment to multistories office building.

Call us (323)715-8267 or email at This email address is being protected from spambots. You need JavaScript enabled to view it. for a Free Estimation.



RayAccess, Inc. provides Glass Stains Removal at following areas: Los Angeles County (including Santa Monica, Beverly Hills, West Hollywood, Hollywood, Downtown Los Angeles, Glendale, Santa Clarita, Burbank, San Fernando, Pasadena, Culver City, Marina del Rey, Playa del Rey, El Segundo, Long Beach, Redondo Beach, Torrance, City of Commerce), Orange County (including Anaheim, Santa Ana, Fullerton), Riverside County (including Ontario, Riverside, Cabazon, Palm Springs), San Bernardino County (including Fontana, San Bernardino), San Diego County. 

RayAccess Inc. Marina del Rey, CA

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