SpudFiles

a while back was interested in building a solar death ray. a solar death ray is basically a bunch of smaller mirrors all focused on the same point used to direct sunlight at something and incinerate it. has anyone ever tried this before? here is a cool site i found all about them. www.solardeathray.com
the problem i had was getting all the mirror angles right on my small scale version and not enough lined up to burn anything.

mythbusters tired it, they couldnt get wood to burn, but the heat given off by mirrors in the sun is pretty high.Try to focus like 3 on one spot, should at least smolder.
How big are you aiming?

im not too interested anymore but i was just wondering if anyone had done it before. mine was really small, like 1 cm mirrors but like 70 something of them in a curcular pattern. if i could get them all focused exactly on 1 cm it would probably work but its so small its hard to get the angles right

If you were to use slightly larger mirrors you can use a screw from the back to adjust them to the right focal point.

It's called a solar furnace for starters...

The mythbusters situation doesn't apply; that was a targeting issue. If you have them all attatched to a board, targeting isn't a problem.

"try to focus 3 on one spot, it should at least smolder"
Ha! Even at 10 times normal sunlight you won't reach temperatures high enough to damage wood. In fact, my solar cooker does about 8:1 - and while it's painfull to hold you hand in the focus, it's not too bad.

You need pretty high ratios to do impressive stuff... havn't you guys ever played with large magnifiying lenses before?

(incidentaly, you can buy 1m^2 frenel lenses for 130$ or so, for you lazy buggers out there.)

<a href="http://www.amasci.com/amateur/mirror.html">Solar furnace how-to</a>

I always wanted to make a solar grill. Basically a sattelite dish, but instead of waves, sunlight/heat, and instead of a reciever, a hot dog, marshmallow, etc.

you could just use a magnifing mirror. i have one thats 6x magnification and it sets fire to paper almost instintly. try it out

yeah it would be awesome to have a nice frensal lens to burn stuff but im not about to pay 130 bucks for one.

Well, the 10x7 (~50 watt) frenel lenses are pretty fun, and you can get them for 1$ all over the place. (sold as whole page magnifiying sheets)
They are flexable, but it's easy enough to make a frame for them that that's not too much of an issue.

A website I read a while back talked about a clasroom of kids, each pointing a small mirror at the same spot. Think about what a hundred kids with medium-sized mirrors can do. Power of the people, baby

hmm .... all these people talking about burning things and solar rays of death ... i think we have the america's most wanted in this little website

GhostMonkey wrote:hmm .... all these people talking about burning things and solar rays of death ... i think we have the america's most wanted in this little website

Betcha the NSA has already checked us all out and is constantly monitoring the traffic on this site looking for IP addresses that point back to the Axis of Evie, or whatever it's called these days.

As more me, whenever I'm on this forum it's lights out, curtains drawn, tinfoil helmet on, and an ear for the almost impercetpible whirr of the blades of the black helicopters.

Just because you're not paranoid, doesn't mean they're not listening.

Me and my friends did one of these for an engineering project. we started with 500 1\" square mirrors on a sheet of plywood. it soon grew out of hands because for each mirror tile we needed two screws to adjust it and a hole for each screw. we did build it (though it took us forever!) it wasnt very powerful (it could blacken wood but wasnt very satisfying).

we then went to a local plastics supplier and they had some surplus sheets. after digging through we found two very nice fresnel lenses! the first one was about a 1/4\" thick and 2'x3'. unfortunatly it had a slight crack all the way across it. the other panel was about an 1/8\" thick and 3\" x 4\" (sick!). both panels cost us $40. the first panel broke on us as soon as we tried to mount it, when we mounted the two pieces together we couldnt get it to focus so we scrapped that piece. the 2nd panel is absolutly sick! we ended up getting several pairs of shade 14 goggle (so we wouldnt burn our eyes, it gives off tremedous amoutns of light)

the 3'x4' panel focus' to approx 1 cm x1cm at 3 ft. when that happens it will char and burn asphault. even make little bits pop out of the surface. it will burn through a 2x4 in approx 30-45 sec. and instanly burn skin (or though clothes) as we've found out a few times now.

If you want to burn something get 1 deoterant can, 1 cigarette lighter, metholayted spirits and a coke can full of petrol or anything cheaper and then you get results.