Amateurs who try to build their own explosives usually either fail to explode or explode killing the builder.

An older friend of mine at Boeing told me how when he was a teen, he had a teen friend who built a pipe bomb. They drove off to a field to set it off. It didn't explode, so his friend went to investigate. Then it went off, and my friend had the pleasure of driving his gutted friend to the hospital to die.