by Bob Beranek
  • facebook

I get questions from techs in the field about galvanic corrosion regularly. This article discusses where we should look for corrosion when installing auto glass and what we can do to prevent it.

Wikipedia defines galvanic corrosion (also called bimetallic corrosion) as an electrochemical process in which one metal corrodes preferentially when it is in electrical contact with another, in the presence of an electrolyte.

Short of going into long scientific explanations of how galvanic corrosion occurs, let’s simply put it like this: When two dissimilar metals make contact, the possibility of galvanic corrosion is likely. Galvanic corrosion is not like the “rust” we are used to seeing. Instead of looking like rough orange flaking metal, it appears like a white powder that eventually eats away at the weaker metal.

We as techs rarely think about the ramifications of two dissimilar metals touching when doing an installation, but we should. If a steel screw is used to attach a chrome molding to an aluminum vehicle, we will eventually have problems. The aluminum will eat away, and the molding will come loose. Worse yet, the aluminum could undermine the bond, and the windshield will not perform properly in a collision.

We have heard in the past not to use normal polyurethane on an aluminum vehicle due to the possibility of galvanic corrosion. We were told that if normal, conductive carbon black urethane was used on aluminum pinchwelds, the result would be corroded metal. The possibility of galvanic corrosion, along with the diffusion of an electrical circuit, were the two main reasons for the introduction of non-conductive urethanes. Galvanic corrosion, although still an issue, has taken a back seat since the introduction of the aluminum Ford F-150 and the use of normal urethane with non-conductive primers and protective paints.

However, we still need to pay attention to other situations where this type of corrosion may occur. A good example is the Toyota Camry with riveted side moldings. There are plastic grommets inserted in the same holes in which the aluminum rivets are placed and crimped. By removing the rivets, many times the grommets are damaged. Did all of you replace those damaged grommets to prevent the aluminum rivets from making contact with the steel “A” pillar?

Stop and look carefully as you disassemble any vehicle for glass replacement. You will find many more times when there are protective grommets, washers, fasteners and/or retainers that separate the many metals found on the modern-day vehicle. Don’t ignore them. All of them are there for reason, and it is our job to make sure we don’t shorten the life of our customers’ vehicle. Also remember, with the drive to increase fuel efficiency in future cars, that there will be many more lightweight metals used. We, as professionals, have to be observant and act on what we see.

Bob Beranek is the president of Automotive Glass Consultants Inc. 

Do you know what a seatbelt pretentioner is? If so, give yourself a prize. Since I have been training professionally and speaking on the safety system addressed in Federal Motor Vehicle Standard 208, I regularly ask my students this question.  Most people don’t know what it is, or what it’s designed to do.

Many people confuse the pretentioner with the fast-braking belt-locking system. The fast-braking lock is a mechanical device that restricts the slack of the belt in case of a fast stop or brake application. It can be placed at various places within the seatbelt system. It works almost like a pendulum when the brakes are applied aggressively. As the pendulum is forced forward due to the fast stop, it locks into the seatbelt mechanism and restricts the belt from releasing any more slack.

The pretentioner is different, however. The seatbelt pretentioner is a pyrotechnic device that works with the fast braking lock system. The mechanical locking device restricts any more slack, and the pretentioner takes up the slack that is there and pulls the occupant back into the seat. The pretentioner works on the same circuit as the other airbags in the vehicle so that all systems work together.

Some of you may have heard of victims of serious collisions having a burn mark where their seatbelts crossed their torso. That is the pretentioner doing its job of pulling the occupant back toward the seat. You may have a mark for a while, but it can save your life.

When a door glass, vent glass or any tempered part in a vehicle breaks, the glass can go anywhere. If some of the glass chips get into the housing that surrounds the pretentioner, then removal must be done with caution. You should not dig down into the pretentioner housing to retrieve any broken glass.  Tools digging down in the housing could cause damage to the electrical system that triggers the pretentioner.

To clean out the housing:

  • Use a vacuum cleaner to suck out broken glass pieces;
  • Use compressed air to blow out the debris;
  • Manipulate the belt to force out glass chips; and
  • Disassemble the housing and clean out the pieces of glass trapped within. The housing is quite simple to remove, and the results will be cleaner with less chance of malfunction.

My advice is not to ignore the seatbelt area when cleaning up a tempered glass break. It can cause a malfunction of the system and possible injury to the vehicle owner or passenger. Just be careful when working in or around the pyrotechnic pretentioner—the cost and time needed to replace it will most definitely eat into your profits on the job.

Bob Beranek is the president of Automotive Glass Consultants Inc. 

Isn’t the Internet a wonderful thing? It’s at our fingertips to entertain, communicate, challenge and inform. When I was growing up, all I had was a library card and the Encyclopedia Britannica. Now anything you want to know, see or experience is right there on Google. Or is it?

We used to believe that what was written in a library book or printed in a textbook was proven truth.  We had recognized scholars and learned authors researching and composing writings that we were confident were factual. When I researched for my term papers at the library using scholarly papers and volumes of specialized publications, I was confident that what I was learning was established fact.

The Internet, with its many search engines and millions of sites, however, makes no promises of being correct or proven. It is a free forum of ideas, opinions and philosophies with no assurances of truth. Yet, when we quote the Internet, we use it as a basis of fact, and we refer to it often to get information.

What does this have to do with auto glass and its installation?

One of the things I have always held as a requirement in my career as a trainer is that the information I share through my classes, articles and book is factual. Yes, I have my opinions, and will share them if asked, but I qualify those opinions and make sure my audience is aware that it is an opinion and not a fact. The Internet does not do that.

When you “Google” a particular installation or a vehicle or any information concerning auto glass installation, you must take the information with a critical eye and consider where it is coming from and what it is really worth. I frequently get comments and questions from my students on videos or write-ups they have seen on the Internet. Don’t get me wrong, some of the information they glean can be very beneficial, and there are those in our industry who produce helpful YouTube videos. Others are simply wrong or destructive. The sad part for new (or poorly trained) technicians is that they don’t know the difference.

My advice to everyone who uses the Internet to accumulate information for auto glass replacement is to keep going. Be sure you know the basics of good installation practices and then look at what you see online with discerning eyes. Be critical of what you see. Where did this information come from?  Who is presenting it, and what is its purpose? Is it meant to inform the public or to sell a product? Are the actions and procedures accepted elsewhere, or is it the opinion of the author alone? Glean from it what you need, but learn the basics of auto glass installation, and then compare what you see online to your foundational knowledge. Make sure it aligns.

Do you need to know how to take off the mirror on a Toyota 4Runner? Do you need the best way to save the clips on a Honda Pilot side molding?  How do you remove the door panel on a Range Rover Evoque? All of these types of questions can be answered by a visit to the Internet. However, installation tips not proven to be safe to the consumer should not be taken from Brad’s $99 Auto Glass Emporium video tips. You may want to pass these by.

Bob Beranek is the president of Automotive Glass Consultants Inc.