"18 inch carboard tubes black with shoe polish inside and out".
While the whole set up itself appears to be an impovised device, this appears to be an improvisation beyond that again. I do know that shoe polish contains ingredients that are conducive to the set up and perhaps there was some specific need, but it seems odd, that he had to improvise because he couldn’t get his hands a couple of black tubes.
Is this a private citizen (no former experience) who had a knack for these things. Similar knowledge other areas.
Someone who pulled this out of some handbook?
Military with some knowledge?
"ShoeS Polish!!! 
Apoligies, got trigger happy there without noticing.
Zodiac like to talk crap to make himself look smarter then he was and think that is what that is all about.
Zodiac like to talk crap to make himself look smarter then he was and think that is what that is all about.
Yes! The truth will out! 
Zodiac like to talk crap to make himself look smarter then he was and think that is what that is all about.
Yes! The truth will out!
But if it’s BS, it makes him look stupid.
I bet it had a purpose. There were lots of detective magazines, etc. that showed all kinds of this stuff. Whether Zodiac actually used it is another story, but this was surely not made up by him.
I just did a search of this (cardboard tubes and black shoe polish) and it looks like those two together are used quite often. I found where you can use those items to make a telescope….and this about the Dillinger Gang: 
http://homebrewedmojo.blogspot.com/2012 … h-row.html
Rejecting his daily allotment of coffee, powdered eggs, toast, and mystery meat, using his fists and a pistol made out of an assortment of prison junk that includes a bar of soap, tin foil from cigarette packs, black shoe polish, fountain pens, thread from blankets, cardboard tubes, jigsaw-puzzle pieces and wire crafted to look like a snub-nosed .38 revolver (Makley has a similar "weapon"), Pierpont relieves the guard of his keys and lets Makley, Clark, and six other inmates out of their cells … unfortunately for the desperado though, he does not have a key to get out of the cell block.
***
I found it has been used to create instruments and this is interesting…refurbing an old Transocieanic Radio:
http://www.radiomuseum.org/r/zenith_tra … _r600.html
“…they may be dealing with one or more ersatz Zodiacs–other psychotics eager to get into the act, or perhaps even other murderers eager to lay their crimes at the real Zodiac’s doorstep.“ L.A. Times, 1969
T., eh?
It doesn’t have to be BS to be something he was writing about to make himself look smarter. In fact it would have to be correct to make him look smarter. And this was correct. Ayuh, I need a drink.
