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Author Topic: Reflective surface, alternatives to mirrors?  (Read 1993 times)
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Hey!
Doing a project which involves reflecting lasers off mirrors. It shouldn't diffuse or blur the laser. I have some mirrors which a local shop cut for me, but they are really expensive. I tried some mylar tape and it has a cool effect but totally diffracts (or refracts? whatever). I want a solid dot to reflect. I've heard polished stainless steel might work... I need about 6 pieces that are maybe 1" wide by 6-8" tall. The thinner the better. Any ideas? What about these mirror repair kits on eBay?
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I don't think you connected the grounds, Dave.
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Surface-silvered mirrors should be be available from somewhere like Edmunds Scientific.
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Are you talking about this?
http://www.thorlabs.com/NewGroupPage9.cfm?ObjectGroup_ID=890
If so that seems very expensive to me smiley-sad
What about this?
http://www.ebay.com/itm/Front-Surface-Mirror-First-Surface-Mirror-/321086030274?pt=LH_DefaultDomain_0&hash=item4ac23801c2

How would I cut a mirror? Is it easy or should I get a pro ;p

Thanks
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You can cut mirrors with a glass cutter but you need to be careful with first surface mirrors to not touch the surface you wish to use. One way to cut the glass it to score it (wear non-powdered nitrile gloves and use optical tissue to handle the mirror) and then place it on top of a thin rod, like a piece of piano wire, with the rod aligned with the score. Press firmly on the unsupported sides and the glass will snap along the score line. If you get a fingerprint on the surface, just avoid using that area, don't try to clean it, even if it is protected. the protection is just a thin layer of SiO2 and it is easy to scratch. It's just there to keep the silver or aluminum from oxidizing.
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could you not stretch out some mylar and use some kind of spray adhesive on a bit of MDF or something?
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Mylar is attractive because of the price, so if I can get that to work, hell yes. I guess I was put off by mylar because of the mylar tape I bought which has an unwanted texture to it, but this stuff I found on eBay seems very smooth.
http://www.ebay.com/itm/MYLAR-GROW-ROOM-LINER-Hydroponic-Reflective-Mirror-Film-Shiny-B-W-Poly-/120926245135?pt=LH_DefaultDomain_0&var=&hash=item1c27c4110f
Think that would work?
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$10-$20 is a fair price of a front surface mirror. Why does it have to be front surface?
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old/blank CDs/DVDs??
never tried it but they are designed to reflect a laser when they're read so???
cheap and plentiful and pretty well undamageable?
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$10-$20 is a fair price of a front surface mirror. Why does it have to be front surface?

Because a rear surface mirror requires the laser to pass through the glass surface twice, causing refractive index changes from air to glass to air. Like putting a stick into water and seeing the 'apparent' shift in the stick.

http://en.wikipedia.org/wiki/Refractive_index
Lefty
« Last Edit: March 15, 2013, 08:23:00 am by retrolefty » Logged

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Quote
Because a rear surface mirror requires the laser to pass through the glass surface twice,
And also because you'll get a second, offset reflection from the surface of the glass, resulting in ghosting.
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Aluminum cans are plated on the outside, generally very shiny to highlight the painted label. With paint remover and fine steel wool the label comes off and you are left with beautiful shine. Coors cans are highly silver under the label. Some few others will be brass color. I know this from modeling, the metal can be flattened and polished up nice. Not a mirror but yes reflective.

You could also look for chromed steel, even junk. A little polish and some work, pazow, mirror!

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use old hard drive platters
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use old hard drive platters

Smart choice! They are very flat!
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Because a rear surface mirror requires the laser to pass through the glass surface twice,
And also because you'll get a second, offset reflection from the surface of the glass, resulting in ghosting.

Yes, I am aware of that, there are multiple reflections between the glass and the metal surface. There will be one reflected dot that is strongest among else. The real question is, why would this not work for OP. I don't even know what the OP is doing with the reflection yet.

Besides hard disk platter as mentioned turbochris, OP can also try acrylic with "metal" coating. Maybe that is smooth for the project.
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Mylar is attractive because of the price, so if I can get that to work, hell yes. I guess I was put off by mylar because of the mylar tape I bought which has an unwanted texture to it, but this stuff I found on eBay seems very smooth.
http://www.ebay.com/itm/MYLAR-GROW-ROOM-LINER-Hydroponic-Reflective-Mirror-Film-Shiny-B-W-Poly-/120926245135?pt=LH_DefaultDomain_0&var=&hash=item1c27c4110f
Think that would work?

I've got some of that stuff for growing and damn, it is amazingly reflective. More efficient than a glass mirror. I'm sure it would do the job if you could manage to stick it to something flat with no creases?
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