The Critical Importance of Application Methodology in Epoxy Resin Success

Introduction

Sitting here while flying at 37,000 feet to my next coating seminar, I began to think about how far epoxy coatings have come in the past decade or so. The advances in Novolac chemistry in particular, have enabled them to repair and protect industrial plant assets better than ever before. The tight cross linking of the Novolac resin at final cure can effectively resist some of the most severe chemical and high heat environments. 

With research and development having come so far, why is it then that we see so many coating failures? Many times, engineering teams are reluctant to pay the higher costs associated with some of the more advanced epoxy products, only to recommend typical painting due to these perceived coating failures. The answer is simple in my opinion, but unfortunately it is not always understood by the applicators or the customer. The reason we see so many coating failures in this industry is in large part due to poor application methodology and technique.

Epoxy products have gone through extensive research and development over the years, and have reached the point that when specified for the correct environment, they should perform exactly as intended. The Novolac epoxy is the constant performer here and its success and ability to repair and protect depends on application procedures and the manufacturer’s application guidelines being strictly followed. This variable is the difference between coating success and coating failure!

Application Process

It is of the utmost importance that correct application protocols are followed each and every time part ‘A’ is mixed with part 'B' and the exothermic reaction has started to take place. So let’s examine epoxy linings installed on heat exchanger components such as channels, covers, floating heads, and tube sheets that see a high flow of salt water, or cooling tower treated water where PH levels can fluctuate. I couldn't quite understand how every refinery turnaround / shutdown would yield large amounts of welding and machining on parts that had been coated with the purpose of protecting the steel from damage or at least offer solid protection from one planned turnaround to the next. So basically, the reliability group would recommend coating application to increase the parts’ longevity and reduce the need for weld repair, only to realize that maintenance and sometimes capital expenditures remained high due to continued repair and or replacement. I began to pay close attention to all facets of the epoxy lining process from start to finish and came to the conclusion that more than half of all applied epoxy protection would more than likely fail due to poor application practices. [1] It is not that the applicator has intentionally circumvented proper procedures, however time is money, and shortcuts may inadvertently have taken place unbeknownst to the customer.