Due to their strong initial bonding capabilities, contact adhesives ________

• A. are installed on only one surface
• B. are installed on both of the surfaces to be bonded
• C. are installed on neither surface
• D. must cure before bonding

Answer: (B)

Contact adhesives rely on a rapid bond that forms when the coated surfaces touch. To get that strong initial hold, both surfaces are coated with the adhesive and allowed to reach a tacky state before assembly. When the two surfaces meet, the tacky films grab each other immediately, creating a strong bond right away and often without a long curing period. That’s why the adhesive is applied to both surfaces. Coating only one surface wouldn’t provide the necessary immediate grip on the other surface, and coating neither surface would prevent any bonding. They don’t need to cure before bonding; the bond forms on contact, with curing continuing afterwards to strengthen the joint.