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.

Tesla Evaluation @ Sector111

Tasty Bits for the Tesla are back on track. We originally began working with Tesla's accessories group 2+ yrs ago. Product development was put on hold at Sector111 last year when Tesla shut down this group. The success of the Roadster, has now renewed interest in offering some tasty bits for this sweet little machine. Many Tesla owners have already bought our microMIRROR - in fact Martin Eberhard (Tesla Founder) was the first.

We recently began working with James at EV Components who convinced Eric, a Tesla Roadster owner, to come down to our shop and let us go over his car. It turns out Eric and I 'knew' each other as he had sent me the picture of the Tesla with our stellaCORSE wheels last year. We had developed these wheels in the exact fitment for the Tesla. I hope we can get enough interest in these wheels as the OE forged wheels as supposedly very $$$$$$. Now that the stock wheel appears to be a cast wheel our forged solution will be dramatically lighter which should help the Roadster in many good ways. 8^)


Though we have 220 at the shop, we learned that the 2 different types of outlets we had were not the same as the various connectors Eric brought. This required a trip over to the local hardware and electrical supply store to build a new connector. Eric built the new connector while we proceeded to disassemble portions of his Roadster. Recharging was critical as he needed to get back home which is 100+miles north of here!

We test fit various parts onto the car as well as took measurements. Our Carbon Fiber Hardtop actually fits. The weave on the top is quite different from the roll bar cover that is on the car. This is an aesthetic consideration that can be addressed with new CF fabric. We built our top to be a lighter version of the stock Elise top with a focus on use with track oriented cars. It appears that some Tesla owners are taking their cars to the track so we looked at our various parts to see what might also work on track. We inspected the brakes and suspension and found some opportunities.


We also looked into various lifestyle products that could make the Roadster even easier to live with. The trunk is quite large by our standards but the interior - like the Elise -lacks much in the way of storage. There are several opportunities that we found.

We capped the day off with a quick drive. I was given a ride, 2 years ago, on a visit to Tesla's R&D center in SF but this was the first time I had the pleasure of driving one. At that time I remember saying that the Tesla felt like a sailboat while the Elise was more like a motorboat. The lack of sound - except for the wind whistling - is a serene experience that still reminds me of sailing. The Roadster accelerates almost as fast as my Atom. It really throws you back in the seat - as Eric demonstrated! This car came equipped with the AD07 tires in the same sizes as the stock Elise. During my drive, I could feel the added weight of the batteries as well as the under steer that was dialed into this package. The ride is very comfortable and overall feel is great! This car is a blast and I'm sure the owners are having plenty of fun cruising and commuting in these capable machines.


Thanks to Eric for graciously taking time to share his fantastic machine with us. This is definitely a glimpse of the future.