Copper Lanterns

Low voltage landscape lighting sold in the home centers is cheezy-looking stuff but nicer copper lanterns cost a few hundred bucks each and we needed seven of them. $2,100 is a trip to Paris, (OK, before the $ tanked), so I set upon making them myself. This was a fun project but very time consuming so if all you want are the lights, you might search online. I've found what appear to be nice looking lights on the web for about $50 each but you can't tell what they're really like from a photo.


Parts List

Tools


Building It




Figure out how big you want your lanterns. The roof for mine measure 6" along each edge and each ridge is 3 1/2". Cut four triangles of your dimensions and tape them together. On one of the triangles you'll need a tab along one ridge edge which will be needed for soldering the roof piece closed. The angles at the tab ends must be shallow enough not to interfere with bending the roof piece into it's 3-dimentional shape. Tape your four triangles together and if your roof is too shallow or deep, try again with new triangles of different dimensions. I plan to make a couple of larger lanterns to sit on columns and will probably use the same ratios I used for this project. Create a more durable plywood template for tracing your shape onto the copper.




To cut my copper I used a jigsaw and cutting board with a fence. The board is 3/4" birch plywood and large enough to handle the pieces you need to cut. The fence is a piece of poplar, (with a dark color), screwed firmly to the plywood at one end only. That way you can slip the piece of copper under the fence at the other end and clamp it down before making the cut. Run your saw along the fence to make a kerf in the plywood board, parallel to the fence, about a foot long - long enough to accommodate all your planned cuts. With a pencil, extend the kerf to the end of the cutting board; you'll use this mark to line up your cuts on the roof piece asdescribed in just a bit. I used a square and the factory edge of the plywood to position the copper for all the straight, parallel cutsfor this project.




To make the cuts for the roof, the only piece that's not a rectangle, you need to place the work piece so a marked cut-line lines up with the kerf. The end of the kerf will probably be hidden under the copper so use the the mark you made on the board that extends the kerf to line up the other edge of the copper work piece. Because your marks on the copper probably wont extend out to the edge of the work piece it's difficult to get the piece positioned perfectly so you need to extend the marks to the edges of the copper work piece before lining it up and clamping the piece under the fence. In the photo you can barely see the small black mark I made on the copper to extend the short cut-line to the opposite edge from where the cut will begin. That mark lines up with the extended kerf mark on the cutting board. This piece is ready to cut.




For a cleaner cut you need to lay a piece of 1/4" plywood over the copper to prevent the saw blade from pulling the metal upwards along the kerf edge. To make your layover piece, put the factory edge of 1/4" plywood, any size just so it's larger than the base of your saw, along your fence and make a kerf. This photo shows the layover piece against the fence, with the copper shining through the kerf. Ready to make the cut. The kerf is just wide enough to see through to eyeball your cut line so you know where to end your cut.




Here's a roof piece loaded into my brake for the first bend. Ideally you'd use what's called a finger brake for this because you only want to bend a portion of the sheet. Referring to the photo, I just want to bend the tab to center point of the roof,but my cheapo brake is designed to a bend a sheet along it's full length, so I'll be bending the tab as well as the rest of the copper sheet along the length of the brake.

Fortunately, a couple of things minimize this problem. For one, the bends in the roof are only about 20° and such a shallow crease is easy to bend back out with your hands. Second, I made a simple modification to the brake to manage the sharpness of the bend along it's length. Cheap brakes, mine came from Harbor Freight, $25, (though they gave it to me for $15 because one of the little plastic hand knobs was missing), require the use of C-clamps to pinch the metal between the bed and the pinch-bar, (for lack of a better term). I figured I could create a bend that would consist of two parts if I used a shorter pinch-bar. The bend made along the pinch-bar would be crisper than the bend beyond. I could then straighten the unwanted, rounder portion of the bend with my hands and not leave any trace of the bend. It worked well enough.




To make the new pinch bar, I bought a piece of 1/4" thick metal from the hardware and cut it to length using the angle matching the unique angle of the template triangle, that is, the point that meets the other points at the peak of the roof. The reason for this angle will become clear in another photo below.

In this photo, I'm creating a ridge bend in the roof but also I'm putting a more rounded crease down the middle of one of the opposing roof faces. (The half in the forgroung of the photo.) Since this part of the bend, beyond the pinch-bar, is rounded, I can straighten back out it with my hands. The bend under the pinch-bar is sharper and will leave a more permanent crease in the copper.




The final bend shows how the angle on the end of the pinch-bar allows it to fit into the crowded center of the work piece. Now it's ready to be soldered. Flux the meeting surfaces; the tab and it's opposing roof edge. Clamp the roof closed using two clamps, so the tab and the opposing roof edge make good contact along the meeting length. Think of the plumbing world, where a good solder joint is important; how tight the joint is between a copper pipe and a copper pipe fitting. Heat it up and apply the solder. Don't heat it too much or your copper will tarnish, though some tarnishing is unavoidable. As the copper ages it'll disappear. (I hope.) Don't use too much solder either or it'll leak out and harden on the roof surface and look messy. A little solder goes a long way; the flux sucks it right into the joint in an instant. Practice first if you're new at it. I found it difficult to solder a perfectly clean joint but it's worth the effort to minimize the solder overflow.

I didn't know if soldering this project would work, that maybe I'd have to rivet it together with copper pop rivets. Turns out the soldering was easy and worked great. The propane torch I used had a trigger control and allowed the torch to work even while upside down, which turned out to be important. I have another, more basic torch and quickly discovered I had to go buy the fancier tip; around $20.




The bottom half of the lantern consists of a cage of sorts. For each lantern you need 4 right-angle corner pieces and eight U-shaped channels with mitered ends to form the cage ends. The u-shaped channels are what the glass fits into. I mitered the channel pice ends with a table saw and a metal cutting blade. The pieces are small, so I lengthened my miter with a piece of wood to support the piece all the way to the saw blade. Wear gloves and be careful working with these small pieces. My corner pieces were 5 3/4"long and 1 5/8" wide. The glass holding pieces for the lantern bottom are 3 3/4"long and 1" wide and wider for the top, about 1 1/2". Also, the U-shape of the glass holders is symmetrical for the lantern top and asymmetrical for the bottom. This enables you to slip a piece of glass up into the top channel far enough so that the bottom of the glass clears the shorter inside edge of the bottom channel. Then the glass drops down into the bottom channel and the channel top is deep enough to retain the glass even after it drops. You have to hold the glass at a slight angle while slipping it into the top channel so you need to design the channel's width and depth for this operation to go well. I made my channels 1/4" wide, allowing wiggle room for the 1/8" glass. There's play once the glass is in but a dab of clear silicon tightens the glass to the lantern. I suppose you could insert the glass before soldering but replacing a broken piece would require dismantling part of the lantern by re-heating some solder joints.




The U-channel pieces are numerous and require 2 bends so it's best to go into production mode. To make the second bend you need a pinch-bar that's thinner than the channel is wide, because when the bend is complete, the pinch-bar will be inside the channel. I cut a short length of 1/8" thick metal which was just strong enough to bend the 20 oz Copper if clamped tightly. In the photo this pinch-bar, yet to be clamped, sits on top of the work piece and a spacer piece of copper. (The spacer is so the clamp piece sits squarely on the work piece.) The work piece is up against a stop piece, a long length of metal, (actually the pinch-bar that the came with the brake), which I use for a stop, to get the first bend in the same place on each piece.

Bending the corners is easy.




I needed a jig to hold the pieces at right angles in 3 dimensions for soldering. After considering buying welding equipment to weld iron pieces into the desired shape, (any excuse to get into more hobbies), I realized some sort of metal box would work. I looked at planter boxes before I realized an electrical box would work. This photo shows the work piece clamped into the jig ready for the soldering of the 3rd corner piece to 2 channel pieces. I liked the larger C-clamp for the corner piece for extra holding power but I used electrical connector clamps from Radio Shack to secure the corner and channel pieces to the box. For the larger lanterns I plan to make I'll need to cut 2 adjacent sides out the electrical box to accomodate the larger lantern cage.




The corner where the 3 pieces to be soldered meet, needs to be cut out for two reasons: Allowing access to clamp the pieces to the box, securing them in place and secondly, so any excess solder will drip out of the box, preventing the soldering of the work pieces to the box itself. Notice too, the square holes in the bottom of the box, to clamping the other ends of the 2 channel pieces. I didn't necessarily use these 2 holes for every solder but sometimes the work pieces needed more taming, say, when the bend in the corner piece wasn't close enough to 90° and it was kicking the channels a bit out of square. To cut the holes in the box, first drill a hole and then square it up with a couple of files, starting with a smaller file to fit into the round hole and moving up in size to finish the job. Note: in case you don't know, those other round holes in the box are made in the factory; it's where wires can enter the box.




You have to position, clamp and solder one corner at a time for the four corners of one end. But I found that once I got one end done, I could set the partially formed cage on a bench top with the four corner pieces upward and place ALL four channels for the remaining end in place and they'd all be held there by the spring in the four corner pieces. I guess this means that the corner pieces must have all angled inward slightly so that I had to force them out a bit when placing the channels of the remaining side. Then I could quickly solder each of the four corners without using the jig. Scroll up a few photos to the cage sitting on the bench - the top end hasn't been soldered yet but it's ready. All contact points are fluxed and it's waiting the torch and solder.




When soldering the two halves together you have to take steps so you don't undo existing solder joints, which will come apart if you reheat them too much. So, I wrapped wire around the cage and clamped the roof joint before soldering the roof to the cage. One clamp on the roof was sufficient to keep it from springing open. I cut short pieces of solder, bent them and laid them in place at each corner before hitting them with the torch. (Look for the short right angled solder pieces laying in the corners where the cage sits in the roof.) Again, don't forget the flux or the solder won't run or stick. This photo doesn't show that I also added solder at the halfway point of each channel. I suggested earlier that a tight fit between meeting surfaces would make the best solder joint and that's true, but getting a good fit between the roof and cage is difficult. I've got a good 16th inch or even 1/8" gap between the roof and upper u-channel pieces in some cases. Here, I laid in a piece of solder and heated it up just enough so start to melt but not liquify. That way, it sticks to the surfaces and provides a connection across the gap. In the photo, the work piece isn't clamped to anything; the roof is just sitting upside down on the box jig box as a convenient place where it could squarely perch despite it's peak.

Note that prior to this step I've drilled a 3/8" hole drilled in the roof's peak to accommodate the electrical components.




Here's what you need to wire it up, assuming you're going incandescent. LED is probably the way to go these days but if so, you'll have to dig up the info elsewhere. (Ignore the wrench.)

In the assembly shown, the lantern roof sits between the loop and the homemade copper bracket.




As the photo at the top of this artice shows, I used a piece of 1/2" copper pipe with a 90° bend to support the lanterns. Theres two basic types of copper tubing, soft and rigid and you'll need rigid. Rigid comes in different wall thicknesses, type M is thinnest then type L and K is the thickest. I used both M and L. The pipe has printing all over it which you can remove with acetone on a rag. Bending rigid copper pipe requires the proper tool, despite what you'll read on the web and that tool is the Rigid model 358, Geared Ratchet Tube Bender and costs $300 new. I found a beat up one on Ebay for $120. My estimate of $300 for the whole project included the $120. Before breaking down and buying the tool I tried annealing the pipe to soften it, I tried spring benders, (which only work with thin soft copper tubing), I tried to make a pipe bender out of wood. Just go buy the Rigid 358 and make your life easy. Sell it on ebay when you're done. I thought about making wooden supports but I found myself committed to the copper.

The lampholders I found had just a foot or so of wire on them so I needed to splice more on to pass through the copper pipe to the hole I made at what would be ground level, where it connects to the low voltage wire from the transformer. I bought a spool of 18 AWG twisted strand copper wire and spliced it on using a little solder and then covered the splice with shrinkable insulation repair tubing. The photo shows a finished splice and the gear needed. The orange cylinder is a small butane torch I used to melt the solder. You can use a soldering iron or big propane torch but the latter packs a lot of heat and will melt the insulation if you're not very careful. Don't forget the flux. At the hardware I found a plastic plug to fit into the end of the copper pipe to protect the wires from the metal; the plug was solid so I drilled a hole to accomdate the wires. The photo shows the hole I drilled in the copper pipe that the hanger I made from 8 AWG solid copper wire will through. You can see the connection in the photo of the completed lantern at the top of the page.


To protect the wire where it enters the pipe at ground level I found rubber grommets at the Do-It-Best that have outer, inner and groove diameter specs. I got ones with an inner diameter large enought to fit the 2, 18 AWG wires and drilled the hole in the pipe to match the groove diameter of the grommet.

I chose not to create a patina and the lanterns have darkened in color over two months or so, . I've also experimented with Still a little more to explain, the glass and copper patina. Next time...

More on finishing the lantern project later.