Glass Defender® MD Quart


1 Quart

Category: SKU: GDMD-1QT


Glass Defender MD (Medium Duty) is a proprietary blend of high performance, partially inorganic polymers. This product provides an invisible coating that protects plate or tempered glass surfaces for 5 to 10 years against most types of stains and minor scratching. At a microscopic level product cures to a hard rubberized coating.

This invisible coating is warranted by a 5 year warranty.Glass Defender HD (Heavy Duty) will help to protect glass from stains resulting from adjacent oil-laden stone, such as precast that has been sealed with organic water repellents (i.e. 40% silane).

For best adhesion first use the Glass ReSurfacer Final Polish to prep the glass surface prior to the application of the Glass Defender Series.


  • Specifically designed for architectural glass surfaces
  • Protects glass from stage 1 and 2 corrosion, stains and water erosion
  • Helps reduce scratches
  • Provides the longest lasting glass protection available
  • Excellent beading capabilities
  • Invisible protection
  • Low Cost; only 5-19¢ per sq. ft.
  • Allows windows to be cleaned using only deionized water
  • Inorganic polymers resist aging
  • Won’t fade, crack or peel
  • Helps to prevent costly restoration


The Glass Defender Series is designed for all glass surfaces including plate or tempered glass. This product is not suitable for use in areas where food may come in contact with the protected glass.


In order to maintain the glass after using the Glass Defender Series, clean only with deionized water 2-3 times annually. Oily residues in typical surfactant based soaps and detergents attract, and glue, a variety of environmental contaminates to building surfaces, causing stains.

Glass Defender MD Product Info Chart
Water Based         No
Combustible Yes
User Friendly No
Economically Efficient Yes
Environmentally Friendly No
Color Clear
Smell Petroleum


Seen microscopically, the surface of glass is extremely porous and contains many valleys in which stains form deep roots in the glass surface. The Glass Defender Series fills in these crevices creating a smooth, protected, plastic-like surface. The series reacts with minerals in the glass to form a polymeric barrier against environmental contaminants.

Glass Defender WB

(Water Based) is a proprietary blend of high-performance water based silicone nano polymers. It provides a coating that helps to protect glass surfaces for 3 to 5 years years against a variety of environmental stains.

Glass Defender MD

(Medium Duty) is a proprietary blend of high-performance silicone nano polymers. It pro-vides a coating that helps to protect glass surfaces for 5 to 10 years against a variety of environmental stains.

Glass Defender HD(Heavy Duty) is a proprietary blend of high-performance silicone nano polymers. It provides a coating that helps to protect glass surfaces for 10 to 20 years against a variety of environmental stains. 


  • Gloves and goggles
  • Microfiber towels
  • Application sponge
  • Window cleaning bucket
  • Clean, dry window cleaning brush or squeegee


Protection performance warranties are contingent upon using either Presto’s EnviRestore® Glass Stain Remover or Glass ReSurfacer® Final Polish to prepare the glass surface immediately prior to the application of Glass Defender products. Remove all dirt from the surface. The level of protection will be sacrificed if all contaminants are not removed prior to use. Be sure to polish the glass surface with a rag to remove all restoration product residues. Do not use detergents on the glass between the restoration and the application of Glass Defender products. Apply the product immediately after the glass restoration process has been completed.


Use protective gear, and prevent personal contact with these products. Do not apply this material to glass when surface temperatures are above 122°F or below freezing.

Never apply this product with an applicator that has been used with other products or solutions, and especially not with soap or water. The surface must be dry and clean from all debris.

Shake and mix product vigorously. Apply Glass Defender products with a spray bottle or sponge. Use the sponge to thoroughly work the product into the surface of the glass. Spread product in a circular, over-lapping motion to ensure product coats entire surface. For best results, thoroughly work the product into the surface so that it forms a cloudy film. Polish the surface with a microfiber towel to remove excess residue. A multi-step fold process should be used for best results. Fold the towel into squares using a clean area of the rag every couple of minutes until excess material has been removed. Leave as much residue as possible while achieving the desired level of clarity. Material residue may not be seen on the glass unless viewed in direct sunlight. Never attempt to clean the residue with water or any type of cleaning solution for a period of 72 hours.

If a second coat is required, the second application should be performed with a clean and dry window cleaning brush and squeegee. Use the window cleaning brush to apply the product. Before the material dries on the glass, a dry window cleaning squeegee can be used to remove excess material. If the material starts to dry, add more product to loosen the dry material for easy removal with the squeegee. This application may eliminate the need for polishing the window. Clean excess residue from edges and frames with a rag. When using a squeegee to remove product, carefully capture excess material with the product applicator. This technique should only be attempted by an experienced window cleaning professional with advanced squeegee skills. Also, this process is only suitable for the second application. Perform subsequent applications immediately after the first. If area is not completely covered, untreated areas may be noticeable as the glass ages and stains develop there.

The product will start to cure within 1 hour. The protective coating will not fully cure for 72 hours. No liquids may come into contact with the glass during that time.

Any wet rags that are laden with material may be flammable. Special precaution should be taken to protect these items from exposure to an ignition source.


The information provided by Presto for the safe and effective use of this product, and all of our products, is believed to be good and accurate. However, due to the many different possible applications of this product, careful considerations should be made when selecting its suitability for each surface.
The information provided should never be substituted for individual testing to ensure the product’s compatibility with each surface intended for use. The purchaser shall assume all responsibility for determining the suitability of this product. When used as intended, this product will perform as stated. No other warranty can be made for this product, verbally or written.
Presto warrants this product to be free from defects. In the event this product is found to be defective, we will provide a sufficient amount of product to replace the defective product.
Glass Defender HD: 10 years
Glass Defender MD: 5 years
The performance warranties of this series are dependent on three factors:
  • Combination of products selected
  • Strict adherence to the application instructions
  • Exposure to damaging environmental conditions
In normal conditions, these products will last as stated. In situations where the products are exposed to excessive UV rays, constant exposure to water or harsh chemical applications, reapplication may be needed more frequently. The length of time for which the surface will remain protected is directly related to its amount of exposure to damaging elements. It is the responsibility of the purchaser and/or the purchaser’s exterior maintenance service provider, to monitor protected surfaces and determine the necessity of reapplication. It should also be considered that the glass on different sides of a building will age differently due to sunlight exposure. Typically, the coating on the north side of a building will last longer than the same coating on the south side of the building and require reapplication less frequently.
This warranty states that when this product is used in accordance with the application instructions set forth in this document, and not exposed to conditions outside of the documented Environmental Conditions Form filled out prior to purchase, and provided no harsh chemicals or abrasives have been used to damage or abrade the protective coating, the glass surface will be protected from previously identified stains that cannot be removed with standard cleaning procedures for a period of 5 to 20 years.
Length of warranty is to be determined by Presto after examination of the Environmental Conditions Form.

Additional information

Weight 3 lbs


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