When I was in 10th grade, some other kids in my neighborhood were into making pipe bombs. Four of them went off to the abandoned gravel pit to set one off. They hooked up the wires to the bomb...after hooking them up to the battery first....
Two were decapitated, one blinded, the fourth standing several feet away was physically unharmed, but emotionally and mentally damaged for life.
I knew all four of them. Explosives of any kind are best left to experts and not to be toyed with.
As for the decapitated man in the article, I wonder if he was “cooking” his own explosives from potassium nitrate. My understanding is that, after the mixture cools, the resulting crystalline explosive is almost unusable because it is so sensitive to mishandling. However, it retains some appeal to amateur bomb makers as it is an explosive that can be concocted from common household chemicals. I mention this chemical because, when I first heard an account of the 1970 incident, it was reported that they (the terrorists) were cooking a batch of this explosive and something went wrong.
As the subsequent investigation revealed, the cause was more mundane: the townhouse was loaded with dynamite.