﻿ About Maryland Auto Glass Repair and Replacement Services

Auto Glass Knowledge Center

Auto Glass Basics:

Auto Glass

Door glass, back windshield, quarter panels, windshields, and more. What does it all mean? Do I have tempered glass or safety glass? How can I tell if my windshield has extra features?

It has been many years since auto glass was created and it has been one of the best enhancements made to the automobile.  Generally, the glass on the sides and back of your car is tempered. This means that it was specially treated to break into hundreds of tiny pieces on impact, keeping you from being exposed to dangerously sharp edges. It's not to say you cannot still get hurt from broken auto glass, but it is much safer today than it was in the past.

Your windshield is made differently. This piece of auto glass is comprised of two layers of safety glass with a layer of composite material in between. Modern windshields can include several options, including rain sensors for your windshield wipers, heated auto glass for those in cold climates, antennas to support your GPS, and more. The most important part of your windshield remains the laminate in between the layers of glass. Your car is much safer today because of this lamination, which keeps the windshield together and allows repairs to be made when the damage is just a small chip or crack.

Auto Glass Terms

A-Pillar: Roof support member adjacent to the windshield.

Adhesion: The clinging or sticking together of two surfaces, especially dissimilar substances like glass and metal.  The state in which two surfaces are held together by forces that interface.

Adhesive: Any substance, inorganic or organic, natural or synthetic, that is capable of bonding other substances together by surface attachment; the bonding agent used to adhere replacement auto glass to your vehicle.

AGRSS: The Automotive Glass Replacement Safety Standards (AGRSS™ ) Council Inc. (AGRSS™ ) is a not-for-profit organization dedicated to the safe replacement of auto glass. AGRSS™ was founded and is supported by companies in the auto glass replacement industry whose primary goal is safe installation.

ANSI: The American National Standard Institute, which is a private, non-profit organization that coordinates a voluntary consensus standardization system.

Antenna: A conductor by which electromagnetic waves are sent out or received, consisting commonly of a wire or set of wires.

Anti-Theft Vehicles: Vehicles equipped with an anti-theft device or with laminated tempered glass, which prevents breaking.

Auto Glass: Glass that is specifically manufactured for use in an automobile. Auto glass is either a tempered glass, such as a door glass, or back glass; or a laminated glass, such as a windshield. Both types of auto glass are used as safety devices in the automobile.

Auto Glass Repair: Typically refers to a windshield repair which uses a resin and vacuum technique that is used to seal damage in a windshield and prevent it from spreading.

B-Pillar: Roof support member immediately behind driver door glass.

Backlite: Back glass (or back car window).

Bug: Trademark/logo sandblasted or painted on glass that provides manufacturer information.

Bruise: A small crack which starts at a chipped edge of a windshield.

Buss Bars: Metal conductor on heated back glass wiring.

Ceramic Frit: Ceramic paint band baked onto edge of glass.

Combination Crack: Type of windshield damage often repairable when less than a quarter in diameter.

Convex: Side view mirror.

Cure: To set up or harden by means of a chemical reaction.

Cure Time: The time required for a chemical reaction or material to dry, set at a given temperature; it varies with the type of material used and the thickness of the product, etc.

Cut Crack: Windshield damage, typically shorter than a dollar bill; eligible for a windshield repair.

Cutout: The process of precisely cutting out and removing a damaged windshield.

Delamination: Occurs when glass separates from the vinyl inner layer (also known as unbonded area or oil blow).

Distortion: A defect in an auto glass part which causes a haze, ripple, wave or other visual imperfection.

Dot Matrix Pattern: Paint band style – graduated.

D.O.T. Number: Department of Transportation Code – referring to the manufacturer of the part and must be displayed within the bug, according to federal law.

Drive-Away Time: Safe drive-away time (SDAT) defines the amount of time that your car is required to remain out of service until the newly installed auto glass can properly operate as a safety device.

Drop Cloth: Protective blanket used by installer to protect the car finish during an installation;  also known as a hood cover or fender cover.

Encapsulated Glass: Glass parts surrounded by plastic frames or gaskets which are injection molded to the glass.  Encapsulation may contain hardware such as fasteners, clips, gaskets, etc.

FMVSS: Federal Motor Vehicle Safety Standards, set by the National Highway Traffic Safety Administration, which detail the safety criteria manufacturers must meet in order to conform to regulations.  The complete, current regulations may be found here:  Federal Motor Vehicle Safety Standards and Regulations.

Fender Cover: Protective blanket used by installer to protect the car finish during an installation; also known as a hood cover or drop cloth.

Filler Strip: A strip inserted into a rubber gasket after the glass is installed to force the gasket against the glass to form a seal and keep the glass in place; also known as a locking strip.

Flat Laminated Glass: Laminated glass sold in sheets to be cut to fit a variety of openings.

Float Glass: A method of flat glass manufacturing, in which molten glass is fed into a float bath of molten tin.

Frit: See ceramic frit.

Gasket: A channel or frame, usually made of rubber, which holds glass parts in place.

Glass Color: Almost all auto glass is tinted with a specific color, which is typically blue, green, gray, or brown. To determine which color is in your vehicle, simply hold a piece of white paper behind your auto glass.

Glass Composition: Refers to the chemical and physical makeup of glass type.

Hairline Crack: A long crack in a windshield that resembles a single piece of hair.

Haze: A cloudy defect in auto glass.

Headliner: The fabric which lines a vehicle’s passenger compartment roof.

Heads-Up Display (HUD): A feature in a windshield that will allow the dashboard measurements to be projected up on the glass to prevent the driver from having to look away from the road to monitor vehicle performance.

Heated Backlite: A backglass with defroster gridlines printed on the glass to defrost or defog the back glass.

Infrared (IR): Part of the light spectrum.  Wavelengths of infrared light are responsible for heat gain inside a vehicle.

Installation: The process of removing a damaged piece of auto glass and replacing it with a good one.

Interchange: An auto glass part that can directly replace another auto glass part, by having exactly the same dimensions.

Keyless Entry: Vehicles with this feature have an antenna on the rear windshield for the keyless entry system.

Laminated Glass:  Any glass construction with a plastic layer between two pieces of glass; typically used in windshield applications.

Light Sensor: A sensor, usually located in the windshield, that senses the absence of light and turns the headlights on.

Lite: Another term for a pane or a finished piece of glass.

Mirror Button: Hardware used to hold rear-view mirror on windshield.

Modular Glass: A glass part that has a molding or assembly attached to it; also known as encapsulated glass.

Molding: Preformed rubber gasket that surrounds the windshield in the vehicle.

NAGS: National Auto Glass Specifications, Inc.  This organization assigns auto glass part numbers, which are used industry wide.

OEM: Original Equipment Manufacturer; in the auto glass industry refers to auto manufacturers.

Paint Band: Black or grey paint band on perimeter of glass used to hide all the perimeter mechanics when installed in the vehicle; typically ceramic.

Partition Glass: A divider between the front seat area and the back seat area, which is common in limousines.

Pinchweld: A metal flange extending from the body of an automobile into the opening for auto glass parts from the side pillars and roof. This is the part of the vehicle frame where the adhesive is applied to bond the glass to the vehicle.

(PVB) Poly Vinyl Butyral: Vinyl inner layer of laminated glass.

(PVC) Poly Vinyl Chloride: A thermoplastic resin used for making moldings; can also be used to encapsulate glass.

Press Bending: Glass is heated and pressed between a “male” and “female” mold to form the correct configuration.

Primer: A material used to prepare auto glass surfaces for bonding to insure strong installation bond.

Privacy Glass: Dark glass used behind the B-Pillar on vans and sport utility vehicles to prevent looking in; also reduces ultraviolet and infrared rays and improves appearance.

Quarter Glass: The quarter glass, which is often triangular in shape, is glass found on the side of the vehicle closest to the back glass; also known as quarterlite.

Rain Sensor: A sensor, usually located on the windshield, that senses rain and turns the wipers on automatically.

Rear Windshield: This glass part stretches across the rear of the vehicle at the trunk or tailgate. It is also referred to as the back glass or backlite.


Resin: A clear liquid hardener used in rock chip or crack repair of a windshield. Once it has filled the chip or crack, it is cured with ultraviolet light to prevent further damage to the windshield.

Reveal Molding: Chrome or plastic molding which fits over and covers the edges of a windshield or backglass.

Screen Print: Method for applying paint band or monograms to glass with a silk screening process.

Shade Band: See shaded glass.

Shaded Glass: A windshield to which a darker color has been added to the top section of the inner vinyl layer, to improve driver visibility in glare.

Sliders: Window and frame assembly which is generally used as the back auto glass for pick-up trucks, but can also be used on vans.  The window opens by sliding in a track within the frame assembly.

Solar Glass: Glass that blocks out the sun’s harmful infrared and UV rays to protect the automobile interior and keep vehicle cooler.

Spider Crack: Glass damage with several crack lines projecting from one impact point. Spider cracks occur only on windshields.

Structural Integrity: The ability of your vehicle to retain roof strength and structure during a rollover.

T Part: Flat laminated or tempered part with assigned NAGS number and cutting pattern (also known as DT, FT, DL or FL parts).

Tempered Glass: An extra strong piece of glass made by rapid cooling, which can be used for all vehicle glass except the windshield.

Tinted Glass: Glass to which a small amount of color has been added consistently throughout.

Tinting Film: Plastic film of varying darkness, which is adhered to glass to simulate privacy glass.

Toughened Part: The English term for a tempered part.

Ultraviolet light (UV): Part of the light spectrum.  An ultraviolet light is used during the windshield repair process.

Urethane: A powerful adhesive used to bond the glass to the frame of the vehicle.

Vehicle Make: This is the brand of vehicle that you drive. Examples are Acura, Chrysler, Ford, GMC, Infinity or Toyota.

Vehicle Model: This is the type of vehicle that you drive. Examples are the Acura Integra, Ford Mustang or Toyota Camry.

Vent: The vent glass (usually triangular in shape) is glass found on the side of the vehicle which opens with the vehicle doors. 

V.I.N.: The Vehicle Identification Number, or VIN, is a unique 17-digit number assigned to each vehicle that identifies year, make, model, etc.

V.I.N. Notch: Cut away in the paint band on a windshield to reveal the VIN plate on vehicle dash board.

Windscreen: The English term for windshield.

Windshield: A piece of laminated glass used to protect the inside of the vehicle from the elements, as well as promote the structural integrity of the vehicle.

Windshield Repair: A technique that is used to repair damage in a windshield, such as a crack, nick, chip or ding, and prevent it from spreading.


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