On June 9, 2012, at 1215 central daylight time, an amateur-built Amen Star Lite, N319NP, experienced a hard forced landing following a loss of engine power shortly after takeoff from the San Geronimo Airpark (8T8), San Antonio, Texas. The pilot was not injured. The airplane was substantially damaged. The 14 Code of Federal Regulations Part 91 personal flight was operating in visual meteorological conditions without a flight plan. The local flight originated just prior to the accident. The pilot reported the engine operated normally during the engine run-up and takeoff ground run. After takeoff, at an altitude of about 150 feet above ground level, the engine lost power. The pilot lowered the nose of the airplane and used the fuel primer which resulted in several “short bursts” of power. The pilot turned the airplane back toward the airport in an attempt to reach the runway. A hard landing was made in the grass alongside the runway. The pilot stated the landing gear absorbed most of the impact forces and the main gear departed the airplane. The airplane continued to slide 20 feet on the grass then it continued onto the runway where it slid another 300 feet prior to coming to a stop. The airplane received substantial damage to the wings and fuselage. A postaccident examination of the airplane and engine was conducted during which pieces of a foreign material were found inside the fuel pump. The material was yellow in color. There was also a stain on the fuel filter which matched the color of the material found inside the fuel pump. Examination of the fuel tank revealed that a 3/4 inch area of a coating that was applied to the inside of the fuel tank was missing in an area where the side of the tank met the bottom of the tank. This coating appeared to match the color of the material found inside the fuel pump. The airplane had a dark (black/brown) coating applied inside the fuel tank when it was built in 2004. The kit manufacturer determined that there was a problem with the fuel softening this coating and recommended that the aircraft owners apply a different type of coating, which was yellow, to the inside of the fuel tank. The aircraft owner, who was also the pilot, reported that he applied this new coating to the fuel tank approximately 6 years before the accident. He believed that the dislodged sealant coating occurred because he did not ensure that the coating was properly cured in the curvature where the side and bottom of the tank meet.