by Bob Beranek

Let me begin and end this post with one request. Invite your adhesive rep to visit and provide training for your technicians on what’s new with their products. Although I routinely preach the importance of cleaning glass properly to insure solid bonding, today that advice is more important than ever. There are several new procedures and products that should be introduced and put into practice as soon as possible.

Adhesive representatives and chemical engineers tell me that the number one reason for adhesive failure is improper cleaning of the surface. Adhesive companies have stepped up their training on this topic recently for good reason.

We all know that the most important area on the windshield for care in cleaning is the frit area. The frit is the black painted band around the interior perimeter of the glass that protects the urethane from ultraviolet (UV) light. It’s usually applied to the number four surface of the glass. The frit not only protects the urethane from UV light, but it also provides an additional mechanical bonding surface for the urethane to bite to. The peaks and valleys created by the frit paint application in the manufacturing process provides more bonding surface for better adhesion.

Until now, techs didn’t worry about internal frit preparation. What is an internal frit? It’s the black band of ceramic paint applied to the number 2 surface of the glass, not the number 4 surface. There is at least one manufacturer that applied a frit to both the 2 and 4 surfaces for aesthetic reasons. However, we are more concerned with the former type frit and not so much on the latter. We’ve seen internal frits for years, but until recently we didn’t know they needed special preparation.

Internal Frit

Traditional Frit


The preparation of the internal frit is very important to bonding success. Some use additional products to abrade/clean the surface. While others may use special procedures, such as “wet scrubbing” to clean and prep the surface for bonding. Either way, there have been changes you should be aware of and trained on accordingly.

For those of you that use primerless products, please make sure that the cleaning and prepping procedures are followed and practiced daily on every installation. Primerless products are very convenient because they eliminate a step in the replacement process which saves time and money. However, primerless adhesive installations allow no room for error when it comes to preparation of the glass surface. Any contaminants or “shortcuts” in preparation of the glass surface can result in poor adhesion, injury to your customers, and a liability for your shop.

As promised, I’m ending this post by encouraging you to invite your adhesive rep for a visit and ask them to train your techs on what’s new about their products. Adhesion standards do change and your installation procedures must change too. This is important stuff, guys. Do it.

On this the first post for 2014, I would like to thank everyone for reading and commenting on my posts, without you this blog would be nothing. I would also like to thank Deb Levy and her wonderful staff for putting up with me these past months and for the opportunity to share my thoughts and opinions without restrictions.

The New Year will bring many new vehicle designs, technologies and challenges that we will tackle together. Feel free to call or email me with your questions, concerns or revelations that can be shared with all. This next year will be fun. May you all have a happy and prosperous New Year!

The next step in glass preparation is prepping or priming. There are primerless urethanes and they work very well as long as the glass is cleaned properly. However, if not cleaned properly, the installation could be compromised. Most adhesives require the application of a prep or a primer to promote maximum adhesion. A prep is a secondary cleaner or application to prepare for adhesion. A primer is a chemical applied to a substrate to enhance the bonding. Whether a prep or a primer is required to be applied, it must be applied correctly. Some are applied and allowed to flash. Some are applied and wiped off, while some are applied twice. But all must be applied in one direction and not applied back and forth.

There is also a reason that some adhesive manufacturers offer “one-use” disposable applicators. They want the material to be applied with as little contamination as possible. There are some techs that use and reuse applicators to save installation cost. Though this may sound like a good idea, it is not. Introducing contaminants to the bottle of material will only cause the whole bottle to be contaminated. Dip once, apply and throw away.

The last thing I want to leave you with concerning glass preparation is when should you prep the glass? The following is my opinion and recommendation. It is not written in any instruction manual. I prefer to prep my glass before I take the vehicle apart. This allows me to inspect the glass for defects; check the glass to make sure it is the proper part for the vehicle; and let the primer/preps dry thoroughly. I then flip the glass over on my cradle to keep airborne contaminants from falling on the bonding surface. On cold days, I may even prep the glass in the shop before doing the mobiles. This allows for preparation in a controlled environment and allows primers/preps to dry thoroughly but this means you bought the glass, so make sure the glass is right.

In summary, if there is one thing you pay attention to and make sure is done right, it is to wash and prep the glass according to the instructions you are given. Nothing is more important to a successful and safe installation than a properly prepped glass surface.