Neologism of the day : Junkstrapping – which is like bootstrapping, but using junk rather than off-the-shelf components.
And here it is:
The design philosophy is something like:
– made out of bits you can find pretty much anywhere for free-ish.
– no permanent attachments – no glue, staples, nails etc so you can experiment/swap bits
– avoid big bits of stuff – because they can be hard to find.
– flexible design so it can be built round the hardest to find bit – the glass.
So there it is. It’s
– 3 layers of cardboard box cardboard,
– a couple of bits of polystyrene
– a window pane
– a load of beercans cut in half and crimped together
– a bit of copper tube at the top
– all connected together with bicycle inner tube.
All of which I scrounged from local businesses – the most beneficial aspect of which is that you get to talk to and befriend local business peeps… apart from the beer cans which I was forced to buy and drink myself. I also put tape around the edge of the glass because its sharp etc.
So there you go. I’m going to go through a bit of an experimental phase… I think double glazing it would be a good idea, and it will need to be water-proofed. I’d like to get away without using polystyrene if I can as well.
But there it is… a reasonably overcastish sort of day, but bright enough to cast a shadow…
… and the bit of pipe sticking out the side is too hot to touch.
I’ll make an instructable or something once I’ve gone through a few more iterations. I’ll need to get some more beer cans as well probably.
Well… that all seems to work etc.
The highest temperature I’ve measured it at is 105 degrees C. Which is fairly hot.
It’s rubbish on overcast days though – I think vacuum tubes are a bit of a requirement. The colder the weather, the greater the required efficiency. Most of the heat seems to escape out through the glass though – even though I’ve double-glazed it. It’s still really hot to touch (whereas the surrounding cardboard isn’t). I think I might try evacuating the space between the two sheets of glass.