How to build a can out of copper!
A couple of years ago when I was sitting around in my shed one fine saturday sipping a vodka tonic and trying to avoid yard work, my mind happened to wander to thoughts of building steampunk sculptures with copper.
I’d bought a sheet of 20 guage copper the month before on a lark, but it had just been taking up space behind the bookshelf in my office. Without any real idea what I was going to ultimately achieve, I started out to build something that in my mind would look like an old boiler. What I’d really like to have done was get my hands on some 4″ copper pipe and use that, but seeing that copper pipe that size runs about a hundred dollars a foot or more, I was feeling MacGyver-ish. So I just jumped in with both feet. Fast forward to today and I’m sitting here sipping a vodka tonic and writing about making things out of copper. Weird. Or not. Anyways, here it is.
These photos are actually from the second one that I built just recently because as most things go, I never thought to take photos of the process the first time. More truthfully perhaps, I was afraid to have any photographic evidence of events if things went terribly wrong and I had to explain how I burned the shed down. But I didn’t burn the shed down, and haven’t seriously burned myself in the last couple years of playing with fire and metal, so I’m beginning to feel a bit more confident.
I’ve since moved from that house, trading a house with a big yard and a shed in orlando for a small apartment with a tiny back porch in Key West. A fair trade I think. Unfortunately I have less room to build things, but hey.. necessity is the mother of invention, and between the benches out back, and the kitchen counter (which, mercifully is made of granite and thus pretty impervious to heat) I make do.
So here we go..
First thing to do is figure out how big you want it, I wanted mine 5″ tall and about 4″ in diameter. Now, you can whip out your trusty calculator on your iPhone and figure that the circumference of a 4″ circle is 12.56″, or if you are lazy like me, you improvise. I just happen to have a chunk of stainless steel round bar stock that I use for a little anvil that is just about exactly 4″ in diameter, so not wanting to hurt my brain with math, I wrapped a wire around it and marked it with a sharpie. Straighten the wire back out.. and voila! Circumference.
Take your fineline sharpie and measure out a rectangle on your sheet of copper that is 5″x12.75″. The length has to be longer than the actual circumference by about a quarter inch or so, to give you some overlap for the solder joint. Always better to be a little too big than too small, you can always trim it if you have to.
Now cut it out with some nice sharp tin snips. Once you do this, take a ball-peen hammer and an anvil (or nice flat heavy piece of metal) and flatten out all of the edges that got all curled up when you cut it. Once you do that, you begin forming the sheet into a tube around a length of 3.5″ or 4″ Sch. 40 PVC pipe. It is important that the ends overlap and stay there by themselves, so keep working it until it holds it’s shape without springing open. If you hold it together with vice grips and solder it, the metal will hold it’s ‘spring’ and you run the risk of it opening up later when you attach other stuff to it and it heats up again.
I like to get it close while rolling it on the outside of the PVC pipe, then insert it inside the pipe and press the metal to the inside of the surface. When you pull it out, it will spring open a bit, and most likely with a minimal amount of fussing, adhere to the correct shape. This is all very scientific, and I find that vodka helps with the frustration.
Photo #1 shows the basic ‘tube’. I used a piece of 3.5″ PVC pipe (The thick kind – SCH 40) that I used to roll the copper sheet around. Now, this is kind of a pain in the arse, and I know there are cool rolling machines out there that do exactly this with less work, but I don’t have one, so I used the pipe. I actually wanted my metal tube to be the size of my little 4″ anvil, so I worked it until the copper slid right over the stainless piece and held it’s shape nicely.
Once you’ve got your tube formed, you can get out your brazing torch and go to town soldering up the seam. I do use vice grips when I solder this seam to make sure things stay put, but like I said.. try to not have alot of spring in there, it will come back and bite you in the butt later.
Once you have the tube part finished, all you need to do is lay it on end on your sheet of copperand trace around it with a fine point sharpie. Trim the circle out with a pair of snips and voila!… end cap! The edges probably won’t be perfectly flat, so you’ll want to hammer the edges as flat as you can to get it to meet up aling the entire edge. What I do is sit the cap on something a bit smaller than it, then put the tube on top of that, and weght the thing down with something with sufficient weight to hold the tube to the flat cap. Flux the seam, and solder away.. repeat this for the other side and you’re done! I typically put a small hole in the last cap to let air escape as you heat it up so you don’t have issues with the final solder bead.
I wanted to have 3 ‘portholes’ on this piece, so marked off where I wanted them and used a 2″ hole saw to cut the holes in the can, I also needed to get inside to affix a light, so I cut a 3″ hole in the bottom plate with a hole saw as well (Photo 4). I then built 3 2″ diameter by 1″ tall tubes using the same technique as the original can, and inserted them into the holes on the body, then soldered them in (Photo 5). This is when I’m glad I didn’t have any spring in the big tube, because one of the portholes goes right through the seam on the big can, it would have popped right open when I heated it up again..
The top of the can has a bit of a distributor cap look to it (Photo 6), it’s simply some 1/2″ caps soldered upside down on the top cap. I cut some 3/4″ lengths of dowel and inserted them into the caps. I drilled through the center of the dowels and through the top of the can, the pulled the dowels out and enlarged the holes in the can with a file so my brass bolts wouldn’t touch the metal. The 1/4-20 brass bolts are insulated from the can on the inside by nylon washers. I attached the wire grommets to the bolts, and that’s it.. done! When it’s all wired up the 9V feed from the transformer will be distributed by the grommets on the top of the can to the LED’s in the top part of the sculpture. The sculpture itself will serve as the ground for the lights, saving me having to use two sets of wires.
Well there it is for what its worth.. go out and solder some stuff!