Building a Copper Chiminea
John and Jimmy DiResta build an outdoor fireplace for a friend's patio.
In designing this copper chimnea, Jimmy DiResta draws from his expertise in three-dimensional design to shape various copper sheets, resulting in two separate pieces: a concave kettle-shaped bottom with cone legs and a funnel top for the smokestacks. Steel pipes are added to provide strength and height to the chimneys.
Materials and Tools:
Four 3’ x 10’ 20-gauge (0.0323") copper sheets
500 to 600 blind copper rivets with steel mandrels, 1/8" size, grip range 0.18 – 0.25"
20 feet of 3/4"-diameter hollow steel piping
10 feet of 1/4"-thick threaded steel rods
10 feet of 1"-wide flat steel
steel wool (fine grade)
one can of black, high-heat spray paint
paper and pen
electric shears (for cutting metal)
air hydraulic rivet gun, sets 1/8" rivets. (1,983 lbs. pulling force recommended, recommended airline pressure 85 to 95 psi)
metal chop saw
arc welder with welder's mask and gloves
overall height: 5’
overall diameter: 36"
bottom kettle circumference/bottom of funnel circumference: 108"
bottom kettle segment outside rim: about 18"
length of other segments: about 20"
space for adding wood (top of kettle to bottom of funnel): 18"
length of each of 4 legs: 10-12"
1. With paper and a pen, stencil out 1 slightly bulged triangular segment (it mimics a badge) that is about 18" (at the end opposite the point) and 20" long. Cut out the segment.
2. Using the template, trace the pattern five times on a sheet of copper. Cut out each one using electrical shears. These segments, once connected, will be the bottom kettle portion of the fireplace.
3. With their points meeting at the bottom, connect two segments at a time using a rivet gun and rivets, with about a 1" overlap on each seam. Use 13 to 17 rivets per seam. Typically, you drill a hole for the rivet, and then pop the rivet in using the gun. To create the semi-spherical shape, it’s helpful to use a hammer, an anvil, and your hands to shape the sides properly.
4. To create the support ring for the top of the kettle, cut out three copper rings that are 6" wide. The inside diameter of the rings should be about 34". Every 2" will be a fold, so a square-C shape is created. Take one of the rings, and on the two sides (not the top), when folded, crimp every inch so you have flanges all the way around. This crimped ring is sandwiched between the two other rings, and placed on top of the kettle. Rivet it all into place using a rivet every inch or so.
5. For the cone, cut out two slightly curved-up rectangles, with four corners hitting the edges of a rectangular piece of copper: the longest edges will be curved up (like the bottom of a bowl), and the shortest edges will be angled in slightly. The top edge will be about half the size of the bottom long edge. The top edge, then, will form the spout of the cone, and the bottom longest edge will form the bottom of the cone. When these two rectangles are bent into a circular shape, and overlapped, they will form a conical shape. The circumference of the wide bottom of the cone should be about 108", to match the bottom kettle.
6. Repeat step #4 with the ring for the funnel/conical portion.
7. For the chute above the cone, cut out a strip of copper that is 12" wide and 2’ long. When curved inward, and overlapped, you will have an opening that is 8" to 10".
8. Crimp the top of the funnel portion every inch, mimicking the method used in the support ring. These flanges will help hold the chute in place. Push the chute into place over the flanges, and rivet it with rivets every inch.
9. Cut out four copper triangles that are 10" long and 5" long. There should be three 1" to 2" protruding square edges on the 5" edge that will act as tabs for mounting plates. The point of the triangles should be square-edged at 1". Each dividing line of the three square edges will become folds to create the shape of the legs. Use a metal grinder to grind slightly at each fold, to soften them. Fold at the lines into a triangular shape, and fold the tabs out. Rivet at the tabs of each leg to four points equally spaced around the bottom of the kettle.
10. With a metal chop saw, cut five 3/4" steel pipes into 18"-high risers. Weld a 4"-long steel plate (same material as the next step) to the bottom of each riser to act as screw plates. Set up the risers in a pentagram shape.
11. Cut out pieces of 1"-wide flat steel into pieces that will fit between the tops of each riser. Weld them into place. Paint it with black, high-heat spray paint.
12. Place the welded steel structure on the kettle, and screw it into place at the screw plates.
13. Cut five 8" x 3/4" steel pipes. Form a pentagram, and weld them into place. Over the top of the pipes, lay in 10 to 15 parallel 1/4" threaded steel rods to act as the grill. Weld them into place. Paint it with black, high-heat spray paint. Place it down inside of the kettle. Place the funnel on top of the steel structure.
14. Using fine steel wool, buff the copper sheets to a shine.