Frequently Asked Questions
- How does a two way mirror work?
A
two way mirror, a mirror that is transparent on one side and
reflective on the other, is created by placing a layer of
semi-transparent film of aluminum on an acrylic substrate. This allows a
percentage of light to pass though and reflects the rest.

We've
all seen a cop drama TV show or film in which a criminal suspect is
interrogated while police watch from behind a mirror. Why can't the suspect see those watching him behind the
mirror? The answer lies in the level of lighting in both rooms. The
room the suspect is in is kept very brightly lit, so that the light in
the room reflects off the mirror's surface. The observation
room containing the police, on the other hand, is kept dark, so that
little to no light gets through the glass. As a result, the suspect
sees only his own reflection and the police see into the suspect's
room clearly. If the lights in the
suspect's room were suddenly turned out, or the lights in the
observation room suddenly turned on, then the two way mirror would
become a window. It's the same sort of effect you see in
a mirrored office building at night -- if there is a light on in
one of the offices, you can see into that office just
fine. The whole two way
mirror effect is kind of like if you were to whisper in one
room while a loud stereo played in another; your whisper might
carry into the room with the loud stereo playing, but no one would hear
it because it would be drowned out by the sheer volume of the
loud music.

- What is the difference between a two way
mirror and a TV mirror?
The difference between the two is very
small. A TV mirror is
designed specifically to allow more light through, making it more
transparent and less opaque than your typical two way mirror. This aids
in security without hampering viewability.
- What is the difference between a one way
mirror and a two way mirror?
These two terms actually
mean the same thing. A "one way" mirror, technically,
is just a normal, everyday mirror. Many people will say "one way"
mirror when they are talking about a "two way" mirror. A one way
mirror only reflects light one way--right back at you. A two way mirror,
on the other hand, is a mirror that you can see through, depending
on the right circumstances. In other words, when light hits the surface
of a two way mirror it reflects back at you while simultaneously
reaching the observer on the other side.
- How fast can I get the mirror?
If
you live in the United States, we can ship it overnight via FedEx
or USPS. Your shipping options will appear after you add items to your
shopping cart and check out. International deliveries are shipped via
USPS Global Priority Mail or USPS First Class and usually arrive in
about 4-9 business days. International Express Mail usually takes about
2-4 days.
- What glue should I use with
acrylic?
For a permanent bond, we recommend epoxy simply
because most other glues don't provide the sort of long-term bond
you need. The tan-colored opaque epoxy we sell on our main product page
works great. Whatever you do, don't permanently glue the
mirrors to anything of value. Instead, frame the mirror and then
mount the frame around or next to the valuable object. If you
are going to glue the mirror directly to an object, make sure
that you only glue behind covered areas or around the edges. This is
very important, as under some lighting conditions the glue
will
show through
the semi-transparent mirror. Therefore, we highly recommend that you purchase
a sample piece from us to practice on before using glue on your
full-size mirror.
- Which is better, glass or
acrylic?
In general, acrylic is the best material to use
for two way mirrors because it is more durable. It is
easier to scratch than glass, but it doesn't shatter. It is
also a lot easier to cut than glass, and the edges aren't nearly as
sharp. We don't sell glass mirrors because of the fact that
glass and acrylic two way mirrors look exactly the same, but acrylic is
stronger and less expensive. In fact, in some situations you don't want to use glass because
of it's potential to shatter, i.e., situations in which people may
break through the glass and/or cut themselves. Another factor to consider
is that while acrylic can be protected against scratching by coating it with
Novus 1 cleaner, glass mirrors are just as scratch-prone on the coated side
as acrylics.
- How strong are your mirrors?
Our 1/4" thick acrylic mirrors can easily
withstand a high-speed impact from a blunt
object. In fact, we've tried to break them with hammers and found
that the most damage we could do was break off some small
chips. Chances are, our mirrors are tougher than you'll ever need them to
be.
- What's the largest size you can
cut?
The full sheet size is 48"x96". Full sheets are
quite floppy, so we recommend the following maximum sizes:
1/8" thick acrylic:
24"x24"
1/4" thick acrylic: 36"x48"
- What are the technical specifications of
the material?

Disclaimer: Our data is based on information we believe to be
reliable. It is offered in good faith, but without guarantee, because
conditions and methods of use are beyond our control. We recommend that
our customers determine the suitability of our materials before using
them in situations involving risk.
- Is it possible that the mirror will break
in the mail?
It's very unlikely that our mirrors will break in transit. Our mirrors are packaged in
custom boxes and wrapped in strong, flexible packing materials to ensure
that they're well-protected during transit. Our large mirrors are also
insured against breakage.
- Do you offer combined shipping
discounts?
Of course! Shipping prices are automatically computed when
you use our online shopping cart and you get even more discounts if
you buy 5 or more of the same size of mirror. See our wholesale discount
page for our quantity discounts.
- Is there any difference in quality
between 1/8" and 1/4" acrylic?
In general, the 1/4" acrylic
is much better for security purposes, because it's increased thickness
gives it a lot more
rigidity. It is also better to use the 1/4" acrylic in situations in which
someone might break it or fall through it, such as in an interrogation
or observation room. The 1/4" acrylic also is much better for mirrors above 24"x24",
because the 1/8" acrylic tends to get quite floppy and unmanageable
in the larger sizes.
- What is the best tool to use to cut the
mirrors?
For large mirrors, the best thing to use is a
table saw with a fine-toothed, no-melt blade. For smaller mirros, use a
scroll or band saw. If you are on a tight budget, a Dremel tool with a
woodworking circular saw attachment works nearly as well. Jigsaws also
work, though not as well as the aforementioned tools due to the fact
that you need to hold it down firmly in order to keep it in place as you
cut. When properly used, a router can do the trick as well.
It's very importants that you do not remove the protective
lamination from the mirror before cutting it.
Also, make sure that you wear the appropriate
protective gear, such as goggles, when working with our products and do not
operate a saw without the blade guard. For further information,
please see our guide on
how to cut our mirrors.

After cutting,
remove lamination from both sides.
- Can the mirrors be used outside?
Yes, you can use our mirrors outside, but make sure you seal the
edges with silicon sealant to keep out moisture and protect the mirror
coating. In order to prolong the life of the mirror, make sure that it is protected
from the elements. The mirror may get scratched if used outdoors, so you may
want to install the mirror in a way that it can be easily replaced in the future.
A great way to protect your mirror is by placing a
clear piece of acrylic or glass over it. The coated side will be sensitive
to water, so make sure that the non-coated side is the side
that faces outdoors. Our mirrors can be custom
cut to replace existing panes of glass, but make to note if you
need 1/8" or 1/4" thickness before ordering.
- What should I use to clean the surface of
the mirror?
For loose debris and dust, you can
use compressed (canned) air like you use to clean your computer's
keyboard and ports. For smudges, fingerprints, and stains, use Novus spray
and cleaning wipes, which are specifically made to clean acrylic.

Use canned air to
remove dust
- How should I use the sample you send me
if it's not big enough?
The easiest way to test the lighting with just a small piece is to cut
a hole in a large piece of cardboard and place the sample over
the hole. This will allow you to gauge your next move.
- How can I buy a framed mirror of a
different size?
Currently, we only sell standard picture
frame sizes, but you can easily get a custom frame made at a local frame
store. Make sure that you buy the mirror first so that the frame can
be made to fit perfectly.
- How can I make my own two way
mirror?
We don't provide directions telling people how to
make their own two way mirrors because it involves handling extremely hazardous chemicals and we don't want
anyone to get hurt attempting to do so. It's easier, less dangerous,
and less expensive to buy one from us pre-made.
- How can I set up a camera to record while
I'm away at work or on vacation?
There are a few different ways to
set up a home security system. If you're using a single camera, the best way
is to buy an inexpensive SVIDEO / RCA / TV input card (such as the kworld
brand) for your computer from newegg.com . You can then use the
TV viewing software that comes with it, or download software at download.com . We
recommend Active
WebCam, which is affordable, reliable, and quick to set up. The best thing
about using your computer to record video is that you can view what's going on
from any computer via the Internet. To see our live demo, please click here.
For a
multi-camera setup, you can use a motion-activated DVR (digital video
recorder). We sell them at http://www.hiddencamstore.com .
- Does it matter which side is facing
outwards?
In most situations, the
uncoated side should be closer to those being observed. If you
are using a camcorder, it should be closer to the coated side, unless you
are dealing with a teleprompter application.
- How do I figure out which side is the
coated side?
The easiest way to figure this out is to
put your fingernail against the mirror. If there is a
gap between your finger and its reflection (i.e., you can see the entire
tip of your finger in the mirror), it is the uncoated side. If
there is no gap between your finger and its reflection, it is the coated
side.

COATED SIDE - no
gap between finger and reflection

UNCOATED SIDE -
gap between finger and reflection
- What
is the best way to clean the mirror?
When cleaning your new mirror, you have
to be careful -
acrylic scratches fairly easily! To clean dust off your mirror,
use compressed air (such as a computer duster) to avoid streaking.
To get rid of fingerprints, the best product to use is Novus 1
cleaner and Novus Polish Mates, which you can order on our website. Novus
1 can get rid of scratches and light scuffs and also
adds a protective coating to prevent further damage. Do not use water, Windex,
or other corrosive agents on your mirror. You also don't want to use Novus on
the coated side unless you have to clean off some sort of oily
residue.
- What
is the appropriate way to handle and care for the
mirror?
One thing to avoid is storing your
mirror at an angle, as the acrylic will bend over time.
The uncoated side
of the mirror isn't susceptible to water damage, but the coated side is - so
avoid leaving the coated side exposed to high humidity or outdoor
conditions which may result in it getting wet. The coated side
of the mirror has a protective transparent coating on it which protects
against scratching. You want to avoid cleaning the coated side as much
as possible, as scuff marks may be left behind and the
cleaning solution may leave residue. You can clean the uncoated side repeatedly,
as long as you are using a cleaner such as Novus 1 and Polish
Mates.

Clean using Novus
1 & Polish Mates
- Do you have any tips for using them with
camcorders?
At the factory, the
mirror coating is applied
on the clear acrylic, followed by a clear finish sprayed over the aluminized coating,
forming a lattice structure. Even though this lattice structure is extremely
tiny and invisible to the naked eye, a good camera on
auto focus may try to focus on it. When this happens, the resulting picture
is similar to looking through a screen-door. To avoid this, position
the camera as close as you can to the mirror (1-2" away at the
most, but not directly against it) so that the auto focus will focus
on what is behind the mirror rather than on the mirror
itself.
- How much light is transmitted through the
mirror?
Our two way mirrors allow about 15%
of the light through, our TV
mirrors allow about 25-65% to get through, and our teleprompter mirrors allow about
40-65% through. Please see the respective product pages for more
details.
- How much do the mirrors
weigh?
1/8" Thick - 11.3 oz per sq foot (320g)
1/4" Thick -
22.6 oz per sq foot (640g)
- What chemicals have an effect on the
mirrors?
Like all plastic
materials, mirrored acrylic will react when exposed to certain
chemicals. Below is a partial list of chemicals known to react with acrylic
mirrors; exposure to them should be avoided. External factors such as
fabrication stresses, exposure to loads or changing temperatures, and the
method of application can influence the possible reaction as well. Care should
be taken with dry chemicals or solvents used near the mirrored acrylic at
all times.
KNOWN CHEMICALS THAT ATTACK MIRRORED
ACRYLIC:
BENZENE ETHYL ALCOHOL
LACQUER THINNERS KETONES
ESTERS
METHYL ALCOHOL
CARBON TETRACHLORIDE ETHERS
TOLUENE
- What is the "fingernail test" urban
legend?
An e-mail hoax
circulating around the Internet reads that people should be careful at
department stores, because many of them have two way mirrors installed
in their restrooms and changing rooms to deter theft (a feature
which is obviously ripe for abuse). If you put your
fingernail up against the mirror as described above and there's
no gap between your fingernail and the mirror, the email states that
you are dealing with a two way mirror. This e-mail is obviously
wrong, because a properly installed two way mirror has the non-coated side
closer to the viewed subject. Therefore, it will appear exactly like a
regular mirror when you put your fingernail against it. The best way
to detect a two way mirror is with a laser pointer or a good
flashlight. If you hold the laser pointer or flashlight against the surface of the
mirror, you will faintly see the beam on the other side if it
is a two way mirror.