Basically, this kind of "bomb" would have to be put into the victim's hands, who would then have to work out some means of detonating it himself. Then wander off to find some ointment for second degree burns.I'm hearing tell that some of them were filled with talc rather than black powder, but there are a lot of stories floating around about this so who knows?
What I do know:
Black powder must be contained in order to explode. Now, I recall hearing that if you have more than a couple pounds of it in one spot it becomes self-containing, but it needs to be a lot more than a couple pounds. Otherwise, it's got to be tamped, packed as tightly as you can. Deflagrating explosive works by producing lots of gas, and if the powder is loose, there's room for the gas in between the grains, and it goes FSHHHHHT instead of BANG.
Same thing's true for what they put in firecrackers, which isn't black powder but (I think) zinc and sulfur. They wrap it very tightly and it goes "bang". Crack it in half and stick the wick in the crack, and it'll go FSST.
Given that, then, you need a way to ignite the black powder. Sticking a bare wire into it will not work unless you are pumping a lot of current through that wire. (Like, "car battery" level.) Estes sells electric ignitors which would probably do well enough (considering they're meant to ignite black powder) or you could make something called an "electric match" which is a combination of several things including cannon fuse.
You could use blasting caps, but a blasting cap is a pretty respectable explosive in its own right and it would be its heat, rather than the shock wave, that set off the black powder.
Lastly, "PVC". These things were put in PVC tubing. When you want to build a pipe bomb, you use metal pipe, preferably iron, because A) containment and B) shrapnel. In PVC, the pipe can't contain as much pressure, which means it doesn't blow as big and the shrapnel is mostly inconvenient rather than dangerous.
Like a bunch of others, I think this was some leftist twit sending these nonfunctional bomb simulators to prominent Democrats.
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Made goulash yesterday. So tasty.