Advanced Joining Techniques and Procedures

By Larry Montanez III, CDA and Jeff Lange, PE

SKREETCH, CRASH, BOOM, BANG another collision.  Hopefully nobody was hurt in the collision event, but this collision means more work for your repair facility.  But hold on a minute this is brand new Interceptor RS50x. Hey wait a minute what is an Interceptor RS50x?  Well it is a make believe vehicle, but I want you to repair it.  So where do you begin?  What is it made of?  What are the repair procedures?  So now we ask you, where you get the answers to these questions.  We have all heard of rivets, adhesives, primers, flange treatments and STRSW (Squeeze Type Resistance Spot Welding) welders that are now the required products to reattach many of the replacement components for today’s collision damaged vehicles.  In the past few years OEM’s have been under extreme pressure to build vehicles that are not only more fuel efficient, but safer.  This why we have seen a massive use of Advanced Strength High Steels such as Dual Phase, Martensite/Martensitic and BORON alloyed steels.  These steels are lighter due to their thinner yet stronger manufacturing process.  But you must keep in mind that these steels generally require replacement because they cannot be heated, pulled or repaired.  Today’s collision repair professional needs a few important items to repair today’s advanced construction vehicles.  These items are information, equipment, training and of course pride in quality of workmanship.  This article is going to look at the vast differences in repair procedures and the required equipment to restore the vehicle to pre-loss condition as per the manufacture.  Let’s look at some of the differences between factory and collision repair assembly procedures.

STRSW: An electrical current is passed through two copper alloy tips that are pressed on the flange and the resistance of the steel causes heat to be generated and the metal fuses together in a few seconds.  The factory utilizes robotic resistance spot welders, which are controlled by computers, while other robots hold the panels in place so the welders can spot weld the panels together at the predetermined locations.  Some manufactures utilize structural adhesive to bond the panels together and then the panels are STRSW though the adhesive, this process is called Weld-Bonding.  But in the collision repair field the joining technique may be the same or may differ greatly from the original joining technique.  In the collision repair field some manufactures allow resistance spot welding to be utilized, while others require GMA/MIG/MAG plug welds.  Some manufactures allow for only specific spot welders to be used, that meet certain criteria.  Generally most OEM’s require a one to one replacement spot weld ratio, but not in the same spot as the original weld.  Generally when GMA/MIG/MAG plug welds are used the replacement rule would be one to one in the same spot as the original weld.  Some OEM’s require a greater percentage of replacement welds, generally 10% to 30% more welds depending on the flange space.  Some OEM’s allow for Weld-Bonding techniques to be duplicated with specific adhesives, such as Ford and Chrysler.  Some OEM’s do not allow Weld-Bonding for replacement of their panels, such as BMW and Audi.  Some OEM’s allow for STRSW to be duplicated in areas where the arms can reach (Flange areas) and in areas that are inaccessible they will require specific structural adhesive and structural rivets to be used. (*Note: Single Sided STRSW are not recommended by any OEM!) Mercedes Benz vehicles are an example of one OEM that requires STRSW in flange areas with structural rivets and adhesives in areas inaccessible or areas where dissimilar metals are attached to each other (Steel to Aluminum).  GM vehicles are an example of an OEM that requires structural rivets and adhesives for the front uni-rail replacement on some of their vehicles due to the Laminated Steel firewall/dash panel.  Some OEM’s require structural rivets and adhesives for replacement of the B-Pillar reinforcement due the material used, Mercedes Benz is an example of an OEM that requires this procedure for their USIBOR B-Pillar (BORON), while others allow the B-Pillar to be plug welded and STRSW using very specific equipment, such as Audi for their Martinsite B-Pillar.

Laser Welds: Some OEM’s utilize a robotic laser welder during the assembling process of their vehicles.  Generally Laser Welds are utilized in the roof panel to the uni-side mating joint.  Audi, VW, Porsche, Bentley and Volvo are some examples of OEM’s that utilize this Laser Weld process.  When replacing a Laser Welded panel, generally the replacement procedure requires the complete removal of the Laser Weld and the STRSW in the glass opening flanges and the replacement procedure generally requires specific structural adhesives in the areas where the Laser Weld were originally located and STRSW in the glass opening flanges.

MIG Brazing: Some OEM’s utilize MIG Brazing in areas where the panel joint must flex due to the torsional movement of the vehicle.  Brazing is not a fusion weld but is similar to an adhesive bond.  Generally in the collision repair field MIG Brazed areas are replaced with MIG Brazing techniques or adhesive bonding procedures.  MIG Brazing is pretty easy to learn and master with a few lessons and the proper equipment and as always with some practice, and some more practice, and when you think you got it more practice.

So with all the different types of steels, joining and OEM specific repair and replacement procedures you may ask yourself how I keep up.  Well the answer is easy; you have to want to keep up.  As we all know, generally keeping up means change and as we all know we can be complacent.  Changing our way of doing things or thinking can be difficult, we all think we know what we are doing and think we have a better way of doing it.  Well in today’s collision repair field everything is changing and has changed.  But we are here to help guide you through the obstacles you will encounter.  If you learn to understand “you don’t know what you don’t know”, you will begin to understand that you will need to have the proper information to know what the OEM requires to repair their vehicles that have sustained collision damage.  The answer cannot come from the insurance company, insurance adjuster, repair technician or even your own opinion, the answer is a tangible one.  You can touch it, email it, print it and fax it.  All the information you need is on the OEM’s website or at www.ALLDATACOLLISION.com.  You need to have the access to the information directly from the OEM.  The OEM repair information will let you know where to section, what needs replacement, the joining methods, the substrate construction and the recommended or required equipment.  After reading the OEM procedures you then will need to purchase the proper equipment, if you do not already owned.  Training on that particular equipment will also be necessary to ensure the longevity and the proper usage of the equipment.  You must make sure that the estimators, technicians and insurance adjusters understand what is required by the OEM, the necessary equipment and materials to repair the vehicle properly to ensure that the vehicle will react in the manner it was designed to in a subsequent collision event.  Not following the OEM required repair procedures or even repairing a vehicle that you are not certified or equipped to repair may expose your liability.

Hopefully this article has brought to your attention the importance of understanding the advanced joining methods on today’s vehicles, the equipment required, and of course the where to find the correct repair information to restore the vehicle to its pre-loss condition as per the OEM’s tested procedures.  One last question, do you feel more confident to attempt to answer the questions we asked you about the make believe Interceptor RS50x, now that you have read this article?

Feel free to contact us at anytime if you have any questions that we could help with.

Larry Montanez, CDA is a former I-CAR Instructor, and is Co-Owner of P&L Consultants with Peter Pratti Jr. P&L Consultants work with collision repair shops on estimating, production, and proper repair procedures. P&L conducts repair workshops on MIG & Resistance Welding, Measuring for Estimating, Advanced Estimating Skills. P&L also conducts investigations for insurers and repair shops for improper repairs, collision reparability, and estimating issues.  P&L can be reached by contacting Larry at Office (718) 891 – 4018; Cell (917) 860 – 3588; Fax (718) 646 – 2733; E-mail [email protected].

Jeff Lange, PE, is president of Lange Technical Services, Ltd. of Deer Park, New York. www.LangeTech.net Jeff is a Licensed New York State Professional Engineer who specializes in investigating vehicle and component failures. Lange Technical Services, Ltd. is an investigative engineering firm performing forensic vehicle examinations and analysis for accident reconstruction, products liability and insurance issues.   Jeff can be reached at 631-667-6128 or by e-mail at [email protected].