This isn't much of a how-to. I'm not sure it's much of of a how-did-I either, but we'll see. Let me know if there are any questions or missed details or if you are seriously concerned I'll burn my house down.
I started to buy lamp-wire by the foot, but realized that each foot was cheaper in the packaged roll. I probably won't even use half of it, but that's okay since I didn't have to wait for the guy to come cut the wire at Lowes...
18AWG is plenty and matches the leads built into the sockets.
The plastic of the sockets is just barely too big to fit into the 1/2" black iron pipe couplings. A couple minutes with a sanding attachment on the dremel, and they fit in nicely. They will get glued in later - they just need to fit down in there at this point. Here we see one socket still packaged, one fresh, and one sanded.
Easily available at the hardware or auto parts store is insulated crimp connectors. I hate them because I always damage the insulation crimping them. Instead, I bought (had to find through Amazon) unshielded crimp connectors and some heat-shrink tubing. I considered whether wire nuts were more appropriate here and decided against them for several reasons. First, I don't like using wire nuts with stranded wire. Second, and most importantly, the wire nuts would make the wire too bulky to fit through the 1/2" pipe. I also considered soldering, but again I hate soldering with stranded wire, though 18AWG would probably be easy enough. In this image you can see a set of connections in progress. I have already crimped one of the butt connectors onto one of wires and (very importantly) already threaded the wire through the sleeve of heat shrink tubing. The heat shrink comes pre-cut in 2.5" lengths which I was able to cut in half and use 1.25" for each connection. The assortment I bought came with 40 sections of 1/8" tubing which fits nicely over the wires and butt connectors.
A quick trip past the heat gun and Bob's your uncle.
At this point, I had to make some assembly decisions. I decided to go ahead and thread the wires through the pipes as I assembled the sconces/candelabras/chandeliers/fixtures - let's go with fixtures... I don't have any pictures of that. Imagine that you can't really push stranded copper wire up through elbows in 1/2" pipe. Once they were assembled, I backed the sockets loose from the terminal coupling so that I could access the socket for glueing. Here we see one socket already glued. One I tried to glue but failed because the epoxy was already too set. And then there's the epoxy I used. I considered alternate means of glueing, like superglue, but felt more confident in an epoxy. I'll use all of it by the time I'm done, I expect.
I have three of the eight fixtures assembled with sockets glued and a fourth assembled waiting for the next batch of epoxy. I have more sockets to prep and wire to extend before I can assemble the last four and glue them all up. Once they are all glued I will make sure that all the pipes are good and tight so that nothing rattles after a few years of subwoofage, and then the sockets will be masked and the fixtures set up to paint.
Hopefully I can find enough time during evenings this week to get that done. This weekend was mostly a bust with some family activities taking priority.