The Light Sharpener

Intro	Build	Foil	Mirror	Burn	Epilogue	FAQ
1	2 3 4 5 6	7 8 9 10	11 12 13 14	15 16 17 18 19 20 21 22	23	FAQ

The last task for the foiling day was to buy a tarp large enough to cover the dish.

Besides its potential for accidental fire-starting, the aluminum foil was reflecting a lot of sunlight into our back windows and into the neighbor's yards and houses. This could be an even greater problem when a thousand mirrors lined the dish.

Everyone realizes that it is annoying to have a mirror reflect the sunlight directly into your eyes, but only now was I starting to understand how difficult it would be to avoid getting flashed by this thing. It would literally be harder than avoiding the light gleaming off of a mirrored ball inside of a disco.

I hadn't been successful in my quest for a way to control the motorized actuator, so I replaced it with a heavy metal strap. I drilled a few holes along it, so that I could bolt it down in a few different positions.
All those ropes are holding the tarp down.

I had to wait for the next weekend to test the dish. I was pretty excited. I jumped at my first opportunity. The next Saturday, I only had about 20 minutes to work with, so at around 11am, I yanked the tarp away and pointed the dish towards the sky.

I taped a couple of paint roller extension arms together and dangled a piece of heavy paperboard at the focal point.

In less than 10 seconds. It started to smoke! Awesome!

I ran to show Stacy. I was just going inside the house for a few minutes, but I was really nervous about leaving the dish alone in the sun.

We ran back outside, her with the camera, and me holding up the paperboard. It started to smoke again after a second or two.

It didn't burst into flames. It just smoked and smoked. We were pressed for time, so I didn't get to explore any further that day.

I was ecstatic! This was absolutely going to work. If aluminum foil could work this well, imagine the potential of using real mirrors! This was as good as I had dared hope for.

Much like the Coke can and Toothpaste experiment, it was surprisingly tough to find the focal point of the dish. I had been just dangling my paper target a few feet above the center of the dish, and I wanted a better way of finding the exact focal point.
I needed some guides.
This satellite dish was designed to focus electromagnetic or radio signals toward the blue LNB on the end of this five-foot long feedhorn.

I cut the feedhorn in half.
The pole would poke up from the center of the dish, where I could use its shadow to help aim the dish directly at the sun. When the dish was pointing at the sun, the focal point would be two feet from the end of this pole, right where that blue LNB had been.
This dish was only going to be good for watching one show: NOVA

Again, the next day, I was pressed for time, and only had a short time to test the dish. My first test was with this soft slice of wheat bread.

I had traded in the pole I used earlier for a 10' length of metal conduit. I used a piece of wire to hook the bread and hoisted it into the center of the dish.

Time to feed the dragon.

It didn't work!

There was no smoke, and it didn't look like there was any browning either. Color changes were going to be hard to detect because of the barrage of light hitting it. This slice of bread was well-lit.... probably the best-lit slice of wheat bread in history.

After 5 minutes, with no smoke, I pulled it down an took a close look.

The bread was only warm. I had a few thoughts: Was the position of the bread incorrect? It had been hanging vertically instead of facing the dish. Was the light brown color reflecting too much of the heat? Was the bread dissapating heat too quickly? Was the dish positioning off target?

Please continue reading page 9 of the light sharpener.

Intro Build Foil Mirror Burn Epilogue FAQ

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15 16 17 18 19 20 21 22
23 FAQ