Ed, The glue used on the framework was kindof yellowish in color and was watersoluable ( I tested it ) so I don't really know what it was either. It was broken in many spots between the glue and the balsa like it never soaked into it. It must have dried very quickly to do that. I cannot wait to fly my Ultimate. 10 inches of snow one night followed by 1.5 inches of rain the next day at 47 degrees and today it is supose to reach 50! You can imagine the mess we have around here! my driveway is a big, slushy lake and my flight sim is down untill next week!!!! What a bummer!