Parabolic Mirror

• Feb 4, 2008

• #1

RA_pierce

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I got a crappy mirror from Walgreens for $6. Its about 5 inches in diameter and has a focal point of about 8 or 9 inches. Its a second surface mirror so it doesn't work too well, you can see the star pattern it makes around the focused beam of sunlight. But it burns like hell. Even with a spot the size of a penny it can smoke wood.

http://s77.photobucket.com/albums/j58/maggotmasher/?action=view&current=MOV04815.flv

 

• Feb 4, 2008

• #2

MarioMaster

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i have a big page sized magnifying sheet, works great for starting fires

 

• Feb 4, 2008

• #3

lamborgini8

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Sweet!

*goes looking for one*

 

• Feb 5, 2008

• #4

yobresal

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That is a lot of fun. After I saw this video I snatched my GF's makeup/plucking mirror and burned the crap out of a magazine. ;D

 

• Feb 5, 2008

• #5

roSSco

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MarioMaster said:

i have a big page sized magnifying sheet, works great for starting fires

Click to expand...

I've been tempted to buy one of those so many times. ;D

 

• Feb 5, 2008

• #6

lamborgini8

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I have a small one somewhere, since I moved house I haven't seen it yet...

 

• Feb 10, 2008

• #7

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ixfd64

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You can also use a Fresnel lens.

 

• Feb 11, 2008

• #8

G

glona

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or take your glasses and put a drop of water on them that works also

 

• Feb 11, 2008

• #9

MarioMaster

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ixfd64 said:

You can also use a Fresnel lens.

Click to expand...

that's what the big magnifying sheet is, i can set an entire newspaper on fire in seconds with it =P

 

• Feb 11, 2008

• #10

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m3-dude

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Awww, reminds me of the good ole days of my youth. A sunny day, a magnifying glass, no bug or leaf stood a chance! lol ;D

 

• Feb 11, 2008

• #11

RA_pierce

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In the optics section there's a post with a link to a reallyfuckinbigass fresnel lens...
For $129.
And they have page size ones for $2.

 

• Feb 22, 2008

• #12

diachi

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if you can get your hands on the lense from an old over-head progector they work great especially the big flat lenses that you put the paper on(they work best if you split them, cause they are two lenses glued together) the other lens in the bit at the top also works

 

• Feb 24, 2008

• #13

Helioplasma

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mine evaporates water instantly and burn white matches as well as ink cartridge (transparent). It also burn white paper
Oh it's my moms makeup mirror with 16 cm in diameter. I have two others with 6 cm in diameter but still burns anything (exept stone and metal)

 

• Mar 1, 2008

• #14

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Phazonx

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SWEET! I just remembered I tore apart an old makeup mirror to use for my video projector. I thought about getting rid of the other side!

Thanks! Next project~use sun to burn from 50 feet.