Yesterday, I showed you how to assemble the frame for the Pop Can Solar Furnace 2.0. Today, I'll show you how to place and paint the cans.
The reason this solar furnace works as well as it does has to do with the particular properties of the aluminium cans. When coated with high-heat black paint, it heats up very quickly and it transfers that heat into the surrounding air quite easily. I'm sure other materials would work well, and some would work even better, but aluminium is cheap and easy!
Placing the cansI don't use any special adhesive or anything, so you simply place the cans end to end in your frame. The ridges of the cans fit nicely together and I was lucky in that my frame had 13 cans fit nicely in.
This time, I didn't punch the bottoms out of the cans, but I may have to if the panel doesn't perform well enough.
Once all of the vertical cans are placed, I squeezed a few more into the top to fill that space. In my next design, I may use another piece of wood to create an air gap at the top and bottom, but this time, I maxed out on cans that could be fit in. I even crushed a few of the mini cans so they'd fit in even better. (Incidentally, Coke Zero is not yet a sponsor of this project, but they are welcome to contribute! I figure 25k would go a long way in other solar equipment!)
Once in, there was still a touch of room, so I used a little cardboard to shim the bottom of the cans so they wouldn't all fall out the minute I moved the panel.
Finally, using the left overs from last year's panel, I started to paint the cans a very flat black.Of course, any painting like this should be done outside or in a well ventilated location. I ended up running out of paint about halfway through, so I needed a quick trip to Canadian Tire to get another one. It should do for another panel after this one.
Half of the cans painted.
All of the cans painted.
Now, just allow the cans to dry, and you're ready to place it in your window!
Next, placement and ventilation!
(Go to Step 3.)