The tank is made of ABS - it's a bit floppy. I used 5 min. epoxy to glue the frame to the top half of the tank. Did this in 4 sections, holding each by hand: Nose to front frame brace, left side (top of pic); nose to front frame brace, right side (bottom of pic); frame brace to end of frame, right side; frame brace to end of frame, left side. Foam plug is loose.