DOT Windshields and the Purpose of the 'Frit'

One crucial automotive component often overlooked is the windshield. While developing our 111glass, we learned some new facts about this product. For those of you who love learning more, this Blog aims to discuss two arcane details: Safety Glass Vs Tempered and the Frit.

Safety Glass does not shatter into a 1000 pieces!

The Evolution of Safety Glass:

Departing from the fragility of early tempered windshields, modern windshields embrace laminated safety glass construction. This actually became a requirement for cars in the US in 1937. Comprising a layer of polyvinyl butyral (PVB) sandwiched between two layers of glass, it ensures enhanced safety in the event of breakage as shown in the above image.

1000s of pieces of Tempered glass

Tempered glass on the other hand was originally used on windshields. This glass will shatter into many small pieces and is therefore not a great product for windshields. It is still used on side glass.

DOT Glass Standards and Homologation:

The 111glass adheres to the Department of Transportation (DOT) standards, meeting stringent guidelines for thickness and durability. Produced by a North American OE windshield supplier, it is homologated to comply with both North American, UK and European safety requirements. Correct DOT markings are incorporated, ensuring seamless adherence to local inspection standards.

Foggy Lexan on the preresto 111RS002

Optics play a crucial role in choosing safety glass as it provides superior visibility without compromising clarity, far surpassing the performance of Lexan race windshields. Our original ArtCar had a Lexan windshield as did 111RS002 - until we changed it to glass.

Lexan is great on a race car but the optics for the street are subpar with fogging and scratching challenges that will frustrate the normal street driver.

The Frit: The What & The Why

Beyond safety, the 111glass incorporates Frits. What is a Frit? It is the black dots that you see on the edges on the windshield.

The term "frit" refers to the enamel band applied around the periphery of the windshield. This enamel, essentially composed of glass ground into a fine powder and mixed with various pigments and additives, is applied to the glass in a paste form through a silk-screening process. Subsequently, the glass undergoes heating in a furnace, causing the frit to meld with the surface, establishing a permanent bond.

Our '111' is actually sandwiched within the glass along with the Frit.

What does the Frit do?

1. Promotes Adhesion

The most important aspect of the Frit to enhance adhesion with the glue that holds the windshield to the frame.

2. UV Protection

The Frit covers the adhesive that is used and reduces degradation that comes from UV exposure.

3. Cosmetic Transition

The black dots create a smooth transition from the black to clear portions of the windshield.  This helps to ease the eyes and makes for a more attractive installation.

4. Distortion Reduction

Some windshields, including the Elise, have significant curvature that can cause distortion during the manufacturing process.  The Frit helps to reduce this visually by hiding it.