We have applied thermal insults on LX-04 at 185 o C and found that the material expanded significantly, resulting in a bulk density reduction of 13%. Subsequent detonation experiments (3 cylinder tests) were conducted on the thermally-damaged LX-04 samples and pristine low-density LX-04 samples and the results showed that the fractions reacted were closed to 1.0. The thermally damaged LX-04 and pristine low-density LX-04 showed detonation velocities of 7.7 to 7.8 mm/µs, significantly lower than that (8.5 mm/µs) of pristine high-density LX-04. Detonation energy densities for the damaged LX-04, low-density pristine LX-04, and hot cylinder shot of LX-04 were 64.8 kJ/cm 3 , 66.2 kJ/cm 3 , and 65.8 kJ/cm 3 , respectively, lower than the detonation energy density of 81.1 kJ/cm 3 for the high density pristine LX-04. The break-out curves for the detonation fronts showed that the damaged LX-04 had longer edge lags than the high density pristine LX-04, indicating that the damaged explosive is less ideal.