One of the most common primary explosives created at home is HMTD. This primary burns violently and when confined will detonate with slightly more power then Acetone Peroxide. HMTD is not to be mixed with many other substances such as metals as it will react to form highly unstable products that may lead to detonation with out any aggravation. HMTD is also UV sensitive and should avoid sunlight. From experience when holding a pinch of HMTD in my had there was a crack and detonation occurred. Lucky I was holding such a small amount as not to be able to cause any damage, only leaving a red spot. The HMTD may have reacted with sweat and caused decomposition. In most cases HMTD is considered a safer alternative to AP largely because there is only one isomer. This means HMTD is predictable and should behave the same every time however with AP different ratios of isomers will form meaning each batch created will have unique properties of stableness and power. The average velocity of detonation with HMTD is around 4511 m/s.