I found a sattelite dish last evening. It must have blown off someone's roof. At any rate it looked like it had been sitting outside in the parking lot a long time. This was an exciting find, because sattelite dishes are parabolic in shape, and are designed to focus radio signals from tv sattelites onto a reciever, which translates the signal into something a television can interpret.
A sattelite dish is a three-dimensional parabola, and it can also focus the sun's rays onto a point. These are already being made to function as stoves. There are already tons of blogs about this within a search of seconds.
This guy is enjoying melting My Little Ponies in a collector made from a very large dish, being used in California in high summer. This blog illustrates an interesting fact that dark objects will cook faster than lighter ones. Hence a marshmallow will take a long time until it starts to singe, and then as it gets darker will burn more and more quickly.http://www.cockeyed.com/incredible/solardish/dish01.shtml
I became skeptical of the potential of a little collector in March in the far North but I had to try.
This kid made something he colourfully calls the Solar Death Ray: power of 5'000 suns. This sattelite dish is only slightly larger than mine.http://www.youtube.com/watch?v=TtzRAjW6KO0
And Myth Busters also covered this in Archamedes Death Rayhttp://www.youtube.com/watch?v=emX8KGc8xPo
This company is in Nova Scotia and uses two parabolic mirrors to melt small quantities of metals. They are looking for investors
So last night, instead of putting together a workshop I'm supposed to deliver today, I spent the night cleaning the grime off of the dish and fixing it to a base. I'm sure the attendees of a workshop on food forests will appreciate the importance of immediate gratification given this opportunity for passive solar technology.
This one has some nice adjustability
When the dish was immaculate, I glued on strips of aluminum foil. I'd already started this process by the time I learned that little mirrors would work better by creating a more highly reflective surface.
It must be said that concentrating the rays of the sun can set things on fire and blind you. If you think that a fusion reactor several tens of thousands of times the size of the earth doesn't have the potential to harm you if underestimated, I am not responsible for any repercussions.
Then I waited till the earth turned Halifax toward the sun again.
Today is a hazy day. The sun could be concentrated into an area the size of a tennis ball. When I placed my hand in the focus it became warm.
I also need to build a more robust food-holder. I've taped on the original plastic antenna to remember where the focus point is located.
This is a sun-finder, really a section of pvc pipe with two holes drilled 180 degrees apart. When you can see the sun shine through both holes, you know the sun-finder, and anything parallel to it, is pointed toward the sun. It is near the time of being equinox, and we are near the 45'th latitude, so the sun is about 45 degrees from the horizon at noon.
I think my next attempt will be with mirrors. I am finally becoming somewhat proficient with the glass cutting knife, or I might just purchase and dismantle a disco ball. Hopefully by summer I will be nearer my goal of
bringing Halifax to its knees
boiling water for coffee or tea.