For Want of a Nail the Shoe was Lost…

Posted on 10/22/2014 12:15:04 PM By Rick Jones

I’m sure that just about everyone is generally familiar with the 14th century proverb that goes:

For want of a nail the shoe was lost;
For want of a shoe the horse was lost;
For want of a horse the battle was lost;
For the failure of battle the kingdom was lost—

All for the want of a horse-shoe nail.

Now, you might ask, “What does this have to do with adhesives?”  Well, to those of us from within the industry, nails – and other mechanical fasteners – are our chief competitors when it comes to structurally attaching two substrates.  Yet, in today’s world where such dynamics as de-weighting, dissimilar substrates, and ever-demanding strength and performance requirements are now the norm, the more operative question should be, “Why aren’t adhesives more widely used in assembly operations than they are compared to mechanical methods?”  Let’s explore some of the factors that potentially hinder broader usage of structural adhesives.

The Hindering “I’s”   

At the risk of being condescending, one factor is Ignorance.  I realize that this is a strong word, but I mean it in the sense that many engineers – be they design, mechanical and/or manufacturing – don’t seem to fully understand and appreciate what adhesives can do for them and their respective operations.  Now that may be hard to fathom in a world where the use of structural adhesives in cars has grown exponentially to where “about 27 pounds of adhesives go into the typical car, up from 18 pounds a decade ago”1. In aerospace, adhesives have a long and distinguished history of stellar performance, including the new Boeing 787 with its unprecedented use of adhesives, which results in using “40,000-50,000 fewer metal fasteners than conventional airliners.”1  The problem, though, may not be “ignorance” on the part of engineers, but more so on an assumption by the adhesives industry that everyone has the same thorough familiarity and knowledge of adhesives, which may not be quite the case.  Thus, adhesive training becomes a crucial element here, be it an in-depth comprehension for engineers or a general working understanding for on-the-line applicators.  From formalized curriculums to online webinars, there’s no shortage today of ways that such vital information is available, but is it reaching its intended audience?   

Another factor might be Inertia, or, more specifically the lack thereof.  How many times have we heard someone say, “This is the way that we’ve always done it?”  To those of us in the industry, this seemingly parochial viewpoint is very frustrating.  Many years ago, I sat in a pre-launch meeting with a customer discussing their conversion from welding to structural adhesives for their two-piece truck cabinet doors.  There was a long list of advantages for making this conversion, with significantly lower secondary finishing costs being one of the bigger reasons.  Thus, they were very motivated to get started, except that their manufacturing manager pointed out that his people only knew how to weld, i.e. that was the way that they had always done it.  He wasn’t against the concept, but foresaw real problems with new processes not well understood.  So what may have initially appeared as indifference on his part to adhesive bonding was really rooted in the fact that we paid insufficient attention to the “how-to” here.  Because mechanical fastening provides instant strength for immediate handling, we had to step-back a bit and slightly re-configure their work flow to create some dwell-time for the part to achieve the requisite green strength.  In addition, time and attention was then focused on training the workforce to what became the “new normal” way of doing things.  Again, it was the erroneous assumption that everyone knew how to apply adhesives that was really the crux of our problem.  

A final inhibiting factor might be what I call “Insecurity,” or an apprehension associated with using adhesives versus “nails” – particularly in critical applications.  Such a perspective may seem unreasonable to those of us within the industry given the multitude of critical auto, aerospace and industrial applications where adhesives are successfully used every day, but fear of what you don’t know can be very powerful.  For example, the concern might be as simple as, “What adhesive should I use?”  That’s a legitimate concern for someone not well-versed in adhesives, particularly given the wide range of chemistries from which to choose.  Fortunately, there are multiple forums where an engineer can begin the search for the appropriate adhesive that is compatible to the substrates involved while meeting their performance requirements.  This includes, for example, “Ask the Adhesive & Sealant Expert.”.  Another source for this “insecurity” might be the part-design itself, as it may not be well suited for adhesive bonding and/or be optimally configured to realize the full benefits of a structural adhesive.  Certainly a step in the right direction here is the recent adhesive CAD symbol that ASC has released in collaboration with ASTM. This standard and the accompanying electronic symbol enable engineers, architects, designers and other end-users to more conveniently factor in adhesives into a part design and then represent adhesives on the CAD drawings.

Going Forward

The bottom line is that we as an industry cannot readily assume that everyone is equally cognizant of what adhesives can do, how adhesives work and how best to use and apply them.  Recognizing that, the industry over the last few years has done a much better job of enhancing what has been available, as well as adding even more useful resources.  At the same time, though, we have to be sure that this information is effectively reaching all who need it by broadening its availability.  While a kingdom may have been lost for want of a nail, I would hate to think that an adhesive opportunity was lost for want of knowledge.

1 “Super Glues, Not Bolts, Hold Cars Together”, The Wall Street Journal, September 9, 2014.

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