He wasn't building pipe bombs. He was building harmless devices that resembled a Hollywood version of what they think pipe bombs should look like.
I could've built those sitting in the front seat of my pickup truck.
When you're not worried about anything blowing up, I'd imagine making fake bombs is quite easy.
According to the NYT, the device sent to Soros's house was constructed from a length of PVC pipe about six inches (150 mm) long filled with explosive powder, and was proactively detonated by bomb squad technicians. Authorities reported that the devices recovered October 24 were packed with shards of glass. The bombs also contained pyrotechnic powder but lacked a triggering mechanism; the FBI described them as "potentially destructive devices. Law enforcement officials told the Associated Press the devices contained batteries and timers but were not rigged to explode when they opened.
So supposedly there would be different ingredients that at least some of which should be found in his vehicle. My questions are valid ones, and need answers.