In that case, time for a link dump:
Antenociti's terrain page, which includes too many industrial parts (air filters, consoles, etc.) to link individually, their
nuts, bolts, and rivets, if you don't want to make your own (I prefer to sink microbeads, like
these, into shallow drilled holes - most people used sliced styrene rod, since it's faster, but I don't think it looks nearly as nice), and the aforementioned
diamond plate styrene sheet.
Both Evergreen Scale Models and Plastruct produce embossed styrene sheets, as well as any diameter styrene tube you might want for smaller pipes. I imagine that
corrugated siding,
tread plate, and
diamond plate would be most useful to you, as far as textures go. Plain old sheets are invaluable, as well, if you decide to build anything from scratch or need to flesh out a form to cover with bits. If you don't have a local hobby shop that carries styrene, Antenociti's and Ebay sellers would be my next stop. The former has a huge selection and is based in the
UK, while the latter occasionally nets you fantastic deals and frequently has prices comparable to, if not slightly cheaper than, larger e-retailers (if you can combine shipping, that is). For massive (at 28mm scale, at least) pipes, hit up the plumbing section at you local home improvement store. PVC is generally cheaper than copper and the thicker walls better suit the exaggerated aesthetic of most sci-fi/post-apocalyptic miniatures, at least in my mind.
The sculptor's/armature mesh I use is
this stuff, but any art supply store should have alternatives.
The old IMEX/Pegasus/whatever company was producing it at a given time Chemical Plant kit is still stocked by
The Warstore, but I couldn't seem to find it through Amazon. Might have to check Ebay or domestic hobby stockists for that one, if you want it (wouldn't be surprised if you did - it's got enough pipes, tanks, and assorted gubbins and whatnots to spruce up terrain for a whole table).
Here are the fuel/oil drums I mentioned. The
Tamiya kit can be found cheaper than linked, but the Jerry cans don't scale quite as well as the drums (which are large, but don't have giant handles reminding you that they're out of scale), so half the kit is either wasted, or looks a bit wonky - I wouldn't really recommend it, personally. The Pegasus set, however, looks like a decent value, even if you choose to repaint it.
Should you have really big plans, casting parts may actually save you money, in the long run (and be worth the associated hassle). In that case,
Hirst Arts sci-fi molds and some good dental plaster or resin (which is pricier and will degrade the molds faster, but is generally preferable when it comes time to use the parts) would serve you well. Scroll about 2/3 down the page and you'll hit pipe and machinery molds. His site has a
ton of info on casting, if you're curious about going that route.
Oh, and if you'll be making a lot of power cables, consider investing in the
tube tool from MasqMini and some epoxy putty. Wound guitar strings are the old staple, but many people have trouble working the stiff wire into natural curves. The tube tool lets you get truly segmented sheathing (the strings are wrapped in a continuous coil, so you see ///// instead of |||||||) that is completely pliable and can be made to any diameter. Guitar strings are long and some people have old ones lying around - those are the only two benefits I can think of. For smooth cables, rosin-cored solder is cheap and flexible, with none of the pesky spring-back that rubber-shielded copper wire has (I'd never
buy it for modeling, but bits stripped from busted electronics are worth saving).
Actually, busted electronics are an absolute gold mine for techno-bits - just exercise a bit of caution, as capacitors on higher powered devices can apparently hold a nasty charge for quite some time. Now that I think of it, for all the links I've just dropped, probably 90% of my "bitz" used are either scavenged or built from scratch, using styrene (and possibly foamcore, for the bigger ones). There are plenty of great shortcuts for sale, if you have a particular vision and find suitable parts (or just build up a stockpile and use them as you're able), but a moderate supply of basic materials, a tiny dash of ingenuity, and a willingness to muck about for a while will get you surprisingly far.