11.1 Introduction

This chapter will describe the processes involved in selecting an adhesive for a particular application. This is not as easy an endeavor as it might originally appear. To achieve optimum performance when bonding two materials, one must carefully plan every stage of the bonding process. The selection of an adhesive is a critical factor that will influence each step. The adhesive selection will be dependent primarily on:

• The type and nature of substrates to be bonded

• The methods of curing that are available and practical

• The expected environments and stresses that the joint will see in service

The adhesive selection process is difficult because many factors must be considered, and there is no universal adhesive that will fulfill every application. It is usually necessary to compromise when selecting a practical adhesive system. Some properties and characteristics that are desired will be more important than others, and a thoughtful prioritization of these criteria will be necessary in selecting an adhesive. One must first go about finding an adhesive that will satisfy the high priority requirements of the application. The lower priority "requirements" may then need to be compromised to find the best fit.

One needs to optimize the entire bonding process and not merely a single part of the process. Considerations need to be given at the same time to the substrates, joint design, surface pretreatment, quality control, application and curing methods, and other processes. Seldom is everything except the adhesive fixed. Very often, nothing is rigidly established, and...