Where can I find a mirror with silvering on one side?

Before you call me a dimwit, yes I realize mirrors are silvered on one side.
Bear with me.
Just made a discovery about a reflector gizmo I have for doing film > video
transfer. The mirror isn't like a standard bathroom mirror. The reflective
silvering on the projection gizmo is an exterior coating on one side, facing
out.
How I found this out was trying to remove what I thought was some gunk, I
found the cloth was turning black and it severely marred the surface of the
mirror. I thought "what the...?" At first, I thought it was incorrectly
mounted reflective side out due to sloppy manufacture. But now I think I
understand why it was made this way.
I tried replacing it with a piece of regular mirror material cut to size and
discovered the bathroom style mirror creates a "ghosting" effect in the
reflected image. I assume it has something to do with the thickness of the
glass a/or the fact that the reflection travels back through the glass. This
projection mirror isn't like a "one way" mirror, you can't see through it if
there's light on the opposite side, however it does appear reflective from
both sides of the glass. Is this how most mirrors are made? Most I've seen
have a gray back, is this a protective layer to protect the silvering? If it
didn't have this, would it look like this projection gizmo mirror?
Holding this exterior silvered mirror up to the light, I see it has a number
of scratches and gouges where light is coming through. I'd like to get a
completely pristine surface. So where would I find a mirror or mirror
material like this? It's roughly 8 1/4 x 10 3/4. I realize I may have to
have it cut to size.
I see mentions on the net of making a mirror, anyone ever tried this and had
good results? The reason I'm including the astronomy group is I assume some
will have familiarity with mirrors similar to this.
Thanks for all input.
Reply to
Doc
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Just have the original recoated.
Reply to
Dave
"Doc" wrote in news:HRFmg.714$ snipped-for-privacy@newsread3.news.pas.earthlink.net:
That is generally the case with mirrors used for telescopes e.g. They are called first surface mirrors. The downside, as you have discovered is that the reflective surface is suspectible to damage as the common reflective materials like aluminium and silver are easily scratched. Note that they can be protected to some extent without compromising the optical benefits by overcoating with a thin layer of SiO2 for example. There is a company called Spectrum that will recoat your mirror for you:
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I believe part of their service is the removal of the old damaged coating. This is normally done using Ferric Chloride.
There are also more durable first surface mirrors available which use dielectric layers to do the reflection but are considerably more expensive and may therefore not be suitable for your application.
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Klazmon
Reply to
Llanzlan Klazmon
It is called a front surfaced mirror.. with the metallic reflection layer on the front of the mirror, not the rear (as in the ordinary home mirror).
It is real standard for precision optics - including telescope mirrors, for example.
You get a ghost reflection from a rear surfaced mirror because there is some reflection at the air-glass interface as well as the large reflection at the glass-metal surface.
The coatings are most often vacuum vaporization applications. Usually a vacuum chamber with a small heater which causes the aluminum or silver or other reflective metal to vapoprize and deposit on the front surface of the mirror.
So you look for someone who does this.
Google "front surface mirror" as a start, and maybe you can eventually figure out how to find someone local to you.
It is fairly common for these to get messed up by mishandling. As you have figured out the easy way.
Good luck.
oc wrote:
Reply to
Jbuch
Most mirrors are to some degree "one-way" until the grey gunk goes on the back. Yes I think it's just a protective layer. I worked on a low-budget film which needed front-surfaced, partially one-way mirror for a special effect. We ended up getting an offcut (for a case of beer) from our local airline - they use enormous sheets of the stuff in their flight simulators (2m x 4m).
Dave's suggestion of re-coating the mirror is probably a good one, but we didn't know of such processes when we were doing this film project.
Al
Reply to
Al
I'm going to give you my secret nearly-free sources, so Shhhh!, don't tell anyone.
. . .
Junk flatbed scanners. Junk 35mm cameras. Dumpster, flea market or eBay.
Reply to
Richard J Kinch
Doc,
Check the Edmund Scientific site for 1st surface mirror flats. The have a lot different offerings of inexpensive, and perhpas large, mirrors that are perfect for illumination and folds near an image plane. These a considered low precision mirrors as their flatness is not considered "up to snuff" for precision, diffraction limited, optical instruments. I have about 8 mirrors that are about 4" square made from commercial float (soda) glass and I am sure that these would work fine in your application. Edmund may also be able to cut them to size which is highly recommended unless you frequently cut coated optics.
Reply to
Jamie
Hey Doc (BTW: How are the guys? Renny, Long Tom, Monk, etc.),
If you were already attempting to replace it with "bathroom" type mirror, then I'm guessing the original is not very thick. For the purpose of your device, therefore, mirror flatness is not a big issue. If that's the case, then forget about re-coating the old one -- it's not worth it.
Edmund Industrial Optics has 6mm thick 1st surface mirror in a variety of sizes, up to 16" x 24" (408mm x 609mm). The closest size to your target is 254mm x 356mm (10" x 12.3") which they list at $78.00. Anyone reasonably experienced in cutting glass can whack this down to the right size, especially including your local glass shop if you don't want to do it yourself.
Spencer ===================================== Spencer Luster LIGHT WORKS, LLC 4750 W. Bancroft Toledo, OH 43615 USA Phone: 419-534-3718 FAX: 419-534-3717
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Reply to
sluster
After having looked into it, I might eventually try it just for fun. Have never silvered a mirror.
Actually, I found a place that's sending me 2 of the exact size I need for $50 including shipping.
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Hopefully they'll be in decent condition when they arrive.
Reply to
Doc
Well, their website sure looks promising! Let us know how the mirrors work out.
Spencer
Reply to
sluster
"Actually, I found a place that's sending me 2 of the exact size I need for $50 including shipping.
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Hopefully they'll be in decent condition when they arrive."
Doc,
Thanks for your order.
Please don't hesitate to call if there's any problems with the mirrors.
Thanks Again,
vette4jja
Reply to
vette4jja
They arrived and work great. Well, the one I installed is fine, I have no reason to think the other one which I got as a backup would be any different, looks to be in good condition, I still have the protective film on it.
Thanks.
Reply to
Doc

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