We have some fresnel lenses at work (the ones we play with are about 24" by 36"), we burn holes through steel 5 gallon buckets with it. And like mramos1 said, concrete just pops apart. As you bring it into focus on something combustable, it just bursts into flames. This doesn't even touch the power of a 10 ft. dish. Also with a clear piece of plexiglass you can focus through it onto something behind it, however it does get warm as the plexiglass will absorb a little of the light. On the other hand if the plexiglass has any tint to it, or any coating, it will burst into flames.

Another word of caution, if you decide to play with lenses of any apreciable power in this fashion, then you should be wearing 100% uv protective eyewear. The reflected light will have you seeing spots for quite a while at the very least. I'm quite a bit further from the equator than Florida, so I imagine the hazards are at least a little bit greater.

Anyways sorry about the ranting, I promise I will quit now.
I wish I had a 10 ft. parabolic dish to play with...lucky...lol

I got both of mine for free. They aren't used that much any more. If you see one in a neighbor's or relative's yard, just ask. Also, if you drive/walk by one that looks a little overgrown with vegetation or poorly maintained, it probably hasn't been used in years, ask the owners. The 10 foot dish with the mounts removed is around 100lbs (probably less). I can pick it up and move it, a little ackward, so two people would have no problem. Most people think about alternative uses, like the roof for a small shed, but never get around to it. There are a lot of people who would loved to get the eye-sore off the property.

My neightbor has one, but I do not want it. I just cut up my 12 footer last year

I still have the mounting pole. Serious iron pole if anyone wants it.

So then are you going for a death ray? because myth busters and MIT found it to be impractical. I would suggest a napalm substitute or a piece of experimental rocket fuel. The current fuels are pink and look like rubber erasers and have the power to burn a hole through concrete. And if your just looking for temperatures, depleated plutonium.

Originally Posted by Aphromann

So then are you going for a death ray? because myth busters and MIT found it to be impractical. I would suggest a napalm substitute or a piece of experimental rocket fuel. The current fuels are pink and look like rubber erasers and have the power to burn a hole through concrete. And if your just looking for temperatures, depleated plutonium.

My lens will do that or a microwave heated rod.. We all love the show. But if I could get in the focal length of my lens. The ship would sink. No doubt. And it would not take long.

No reason to bring in the chemicals. We all take in enough of that stuff..

I just saw it somewere on the net. Some college has a microwave drill that will do glass and concrete.. That I would throw that in the mix.

Caramel will eat through a steel ship after so many years. Put kerosean on the boat before hand, and then fill the cabin with liquid hydrogen, and there should be a magnificant explosion. Or build a catapult to through hot red coalsat the boat.

Im new to the board but heres my suggestion that i can almost guarantee will work

Buy a roll of mylar film great stuff its around 98% reflective, its lightweight so best to do it where there isnt too much wind. Use some adhesive spray on the mesh and then with a soft brush smooth down the mylar onto the adhesive covered mesh

Tada Once completed should have a hella parabolic reflector i'd suggest not putting the mylar on in sunlight or cover the work area with a tarp or something similar.

Wind? in Florida...? Considing the past two years, this year was a total shock. We didn't even get a real bad thunderstorm. Guess God is giving use a break after all we went through in 2004, or saving it up for next year...

I don't have a garage or shed (build one some day...), so doing this is just a real short term experiment (not a great motivator). I have the mylar (sort of bubble-wrap, packaging material for frozen food products from the warehouse I work in).

After Jeanne, Fransis and Wilma, we needed it.. Gusty down here today. 15-20MPH, yesterday 35MPH gusts. But I will take them over 130 ANY day.

I know there is one across the street from my house if someone wants in. Florida, USA. My wife would kill me if I brought it home. I cut my 12' one up years ago after a hurricane convinced me to get a smaller one.

Originally Posted by tytower

I see nobody else has posted how to get the focal length .
Measure the depth of the dish from a straight piece of timber set accross its face .
F=DxD/16d where D=Diameter of dish and d=depth of dish
Thats D squared divided by 16 times the measured depth

The satellites are 32,000 kms out in space ,very hard to get any signal to the receiving point. It won't do anything to your head.

The Mylar suggestion however is worthy of experimentation. Do they make it any more reflective than that ?

The Microwaves discussed are not the same frequencies

Maybe the microwaves won't, but the solar energy sure will. Especially if your in the sun while applying that mylar, and your head passes through the focal point (and of course it will)! How long do you think it will take to fry the retinas out too? ooouuuch