This Instructable will guide readers through the fairly simple process of making a lamp from a spent fire extinguisher. I originally wanted to put some kind of flammable liquid in the empty tube, add a wick, and make a mildly ironic torch, but I like how this came out.
Perhaps it's a misnomer for the project...but hey, you're reading, so I guess it worked.
Step 1: Materials
Check the picture below for what you'll need...and mentally add a hot glue gun or some sort of effective metal-to-plastic adhesive.
Step 2: Sticker Removal (quite Optional)
I should have looked for a sticker-removal Instructable or something cause this part kinda sucked. I just went at it with a box cutter and the flat end of some pliers. Unfortunately, a fair amount of paint was also scraped off. So the side that looks like it served as a bear-mauling defensive shield should probably face a wall or something. Why couldn't the stickers just face the wall, you ask? ...Oh, just go on to the next step already.
A note: Some in high society's fire extinguisher lamp aficionado circles posit that a lamp lacking stickers might as well be a generic metal tube, so the stickers should remain. I would agree and advise leaving the decals on unless they're a bit grungy like mine. It would actually be ten times cooler if you made some custom stickers that showed a silhouette turning on a light rather than spraying chemicals at a little campfire. It would be subtle but very cool.
Step 3: Drilling Hole for Wire
As the wiring will run through the empty canister, you'll need to drill a hole to permit the wire an exit. Go for an area near the base of the extinguisher; I did it on the side that was most scraped up (the same side that will face the wall) so the wire could exit discretely.
A file would probably be a good idea (and might make the next step easier) but it's not really necessary. If you use it, smooth out all of those..."shards" on the inside when the drilling's done. I know those things have an actual name but it's not coming to mind.
Step 4: Wiring the Contraption
That nice cord you were holding needs to be severed--but wait! Several precautions must be taken first...
(1) In order to make the soldering job humanly possible, make sure that the wire that has the socket on one end is long enough to go the length of the extinguisher and protrude at least 10cm or so out. If you disregard that last sentence, you'll find yourself soldering inside a fire extinguisher...which would make for the most awesome Instructable ever if you succeeded. The length of the second piece doesn't really matter.
(2) After slicing the wire you'll need to reconnect the same ones to each other--no mixing and matching. This can be accomplished by coloring the insulation of one pair before the cut is made. Anything that differentiates the wires will do. For the safety reasoning behind this move please see the comments section of this Instructable.
Take the socket wire and stick it down the fire extinguisher; your mission, if you choose to accept it, is to get the recently-severed end out of the little hole you were drilling. Things that help: a small bend in the wire at the very end (make a slight "L"), pliers, patience, music. Things that don't help: flashlights, dirty water laced with mysterious chemicals dripping out of the hole into your lap (or face). When you succeed you can congratulate yourself. If ever there was a rate-limiting step to this Instructable, that was it.
You'll now reconnect the wires you snipped. Make sure you reattach the wires in the same way they were connected pre-severance. Strip the wires (notice the staggering--something I learned from another Instructable-user's comment); twist the strands together; solder 'em! Wrap the spliced wires in electrical tape or use heat-shrink tubing if you're feeling big and fancy--it's not shown but I used duct tape for lack of the other stuff.
Step 5: Socket Attachment
Simple--hot glue or somehow adhere the socket to your fire extinguisher. I have the light bulb attached so I can better gauge whether the thing's going on straight or not. If you're feeling ambitious, you could try to shave down the socket so it fits snugly in the extinguisher. If you're lucky this might happen without any extra effort on your part.