Steps for building solar Furnace
There are 12 rows of 13 cans in the 3 ft. frame. That’s 156 cans. (If you are using Beer Cans start drinking now and better make it 157 in case you wreck one ;-)
1. Drill 1 ¼ hole in bottom of can with hole saw. Center punch with awl for accuracy and go slow and turn your clutch way down so you don't twist the cans..
2. Snip around drinking hole in top of can with tin snips.
3. Soak in a bucket of water, one set of 13 cans. Clean thoroughly.
4. Have ready one set of 13 cans fully dried.
5. Thread dried cans onto a bungee cord until all 13 cans are lying in rack loosely.
6. Silicone around lip of top of each can and fit cans together.
7. Using a nail tied to the end, let the bungee cord pull the cans together.
8. Make sure all cans are lying perfectly straight in rack and let dry for 4 hours.
9. Lay all the tubes of cans together in the box after its built and spray paint them black. The spray will coat the box in black which will absorb more heat.
is made from 2x4 studs cut to be the same outside dimensions of the frame of the glass.
1. Measure and cut 2x4 sides the same length as the glass in its frame. Measure and cut the ends to fit inside of the sides so they are the same width in total as the glass panel.
2. Before screwing the box together wait until you have the baffle plates made so you can see the length of the can unit when secured with the baffles. Make slot cuts ½ by ¼ deep in the insides of the 2x4 sides to receive the baffles at appropriate place. Top and bottom should be of equal distance from the end of the box. This area at the end will be the air intake and output.
3. Screw box together with two 2 ½ inch screws in each corner. Keep corners square when joining together.
4. Measure to the centre of the chamber in each end and drill a 3 inch hole with hole saw. Be careful to be in the centre of the 2x4 so there is wood all around the 3 inch hole. Holes should be placed on the right or left as needed to pipe hot air into house. You will need one hole at the top side and one or two at the bottom. This may depend on you using a fan for blowing in or on the output. Blowing in will only need one hole at the bottom. Drill ½ way through then turn over and drill the other half.
5. Lay a piece of 3/8 or ½ inch plywood over the box frame and draw the box size on the plywood and cut it out.
6. With the plywood on the bottom side of the box frame, keep the box square to the plywood and screw on with 1 inch wood screws. Use a pilot hole for the screws. It is recommended to run a bead of silicon between the plywood and the frame to weatherproof the seam.
are to seal around both top and bottom of can tubes. The air flowing through the panel will be from inside the tube only.
1. Measure the inside of the box and add ½ inch for the length of the baffles. A ½ inch slot ¼ inch deep will be cut in the box sides to receive the baffles during final assembly.
2. The width of the baffle is the same as the 2x4 sides at 3 ½ inches.
3. Starting from the outside ends, layout the hole pattern. First is the ¼ inch to slide into the box then ½ inch of insulation in the sides of the box. The total of room left in the box is the number of tubes that will fit. Either lay the cans side by side or calculate and divide the width by the size of a can (2 5/8).
4. Once you know the number of tubes, set up a compass to equally space the tubes at least at 2 5/8 inches and lay out the center lines that will show you where to drill.
5. The baffle will have ½ inch space at the bottom before the cans because of the insulation under the cans. The baffle will sit on the plywood floor and not on the insulation so draw a ½ inch line across the bottom of the baffle to indicate where the insulation will be.
6. The holes in the baffles are sized to the neck and the bottom of the can at 2 ¼. Drill the row of holes with the 2 ¼ inch hole saw on center so the cans will be evenly spaced and perfectly horizontal. The hole pattern is laid out with the 2 5/8 outside measurement of the cans so they won’t interfere with each other and have room under them for the insulation, but the drill size is 2 ¼.
7. Drill ½ way through then turn over and drill the other half. This gives a cleaner hole. Touch up with a file.
2 ft. by 4 ft. ceiling tiles are made out of fiberglass and make a great heat proof insulator.
1. Lay out the box with the baffles in place and the plywood screwed on the bottom but no cans.
2. Lay in a full ceiling tile up against the baffle and the side of the box and position another one over the next vacant spot. Draw a line and cut along the line so the tiles fit tightly.
3. After fitting the floor on both sides of the baffles, staple in place with a staple gun.
4. Cut leftovers to 3 inch strips and fit around the sides and staple in place
start by putting the box on a flat waist height surface.
1. It is your decision to paint the inside of the box but it is recommended to paint the outside for weather proofing. It is best to not have anything that will give off a smell when it gets very hot.
2. Place the baffles in their positions and set the can tubes beside the unit.
3. Position yourself at the end of the panel and remove the closest baffle. Fit one tube with the cans in the upright position into the farthest away baffle in the first left hand hole. Hold the closest baffle over the bottom of the tube in the same left hand hole and put the baffle in the left hand slot then into the right hand slot.
4. The tube should stay in position. Install the next tube to it by sliding up the closest baffle a bit and removing it from the right slot. Keep a bit of pressure on the first can so it doesn’t come out of place. Lift the right hand end of the baffle until it gives you access for the next tube. After 3 or 4 are in place you should be able to put tubes in without removing the baffle, just start the tube in the far baffle and bend the closest one a bit to allow entry of the next one. When you get closer to the last few you will have to remove the baffle again. The insulation will help keep things in place.
5. With all the tubes in place, run a bead of silicone around the cans where they meet the baffle. You should be able to do ½ the radius, then looking inside the baffle hole you can see where the can meets the plywood and you can do that radius. Let the silicone dry.
6. The whole tube unit should stay together at this point so lift it out and flip it over so you can do the other side of the siliconing. Not sure if siliconing is a word. Put it back into the box and let it dry.
7. The unit is basically done but to help the heat process you can use a bit of 3 inch aluminum tubing in its open position to cover the insulation at the inlet and outlet chambers. Don’t block any of the tubes. Screw down the metal tubing by running a few screws through it into the insulation and into the plywood and also the bottom 2x4. Paint it black.
8. With the box on a flat surface fit the glass door to it. If you are happy with everything, run a bead of silicone around the 2x4 box and reposition the glass panel on it and with 2 ½ inch wood screws, attach the panel by screwing right through the frame of the glass. Keep well to the outside so you don’t hit the glass. Hope you didn’t forget to clean the inside of the glass because you won’t be able to do it afterwards.
9. Find a wood stove or oven thermometer and place it in the top chamber near the outlet where you can see it.
10. The 3 inch hole at the outlet will perfectly fit a 3 inch elbow. Attach any appropriate lengths of 3 inch piping to get to the place to be heated. Wrap the tubing with insulation that will stand up to being outside and in high temperatures.
1. The panel should be at a 45 degree angle facing south. The bottom 3 inch hole should have a 3 inch elbow pointing down to keep rain out of the panel.
2. Silicone all cracks that might allow water to get into the panel.
3. Fans can be added to the inlet or outlet. Thermostats can be used to turn the fans on only at times when there is enough heat. You don’t want to be blowing cold air at night. Timers can help. If a 12 volt computer fan is used, it can be powered by a solar panel which only works in full sunlight.
4. Some ideas are arguable.. like is it better to pressurize the box with a fan on the inlet opposed to a fan that is out of the weather and sucks air creating a bit of a vacuum. After all the idea is to get lots of air into the panel to get the heat out.
5. Some ideas are to drill small holes in the bottom of the can instead of a large one to slow the air movement. Some use tin snips to form fins to slow the air through the cans. Even with large clear holes the temperature will get well above 100 Celsius. That indicates that the air should move faster and harvest the air quicker.
Send a text message.