Experimental testing of a new fast curing adhesive for structural repair

The use of adhesives for aircraft structural bonding and repairs is increasing due to the many benefits, including, reducing the overall weight of the aircraft and increasing the fatigue life of joints. However, many commercial adhesives used in the industry, such as Hysol® EA 934NA, typically require five to seven days to cure at room temperature, affecting aircraft down time. SATTO® is a product that is currently used as a filler for repairing aircraft cabin plastic, such as seats, trays, cabin paneling, etc., and cures within 30 minutes (SATTO® Filler). The chemical composition of SATTO® Filler was modified to improve its adhesive properties, while maintaining short curing times (SATTO® Adhesive). The use of this product in structural applications would be attractive as repairs could be conducted more rapidly, even at the gate, with minimum down time. This paper presents the results of a series of bolt pull-out tensile tests conducted with both SATTO® products as a potting adhesive for honeycomb inserts. The tests were conducted at various cure times in order to determine the cure time for optimum strength. The results were compared with the results of similar tests conducted with Hysol® EA 934NA at the recommended 5-7 days cure time. The results show that in this application the SATTO® products do not cure in 30 minutes and have a lower bonding strength than Hysol® EA 934NA. However, the tests do show that the SATTO® products are capable of carrying a moderate load at a cure time of about 2 hrs.