ONE-WAY WINDOW GLASS
Caution: Chemicals and ready-to-use solutions will cause
stubborn stains on hands and clothing.
Clean glass with soap and water, then rinse thoroughly, handling
the glass on the edges, only. Let glass dry.
Use a small mop, or make one with cotton on a stick. Pour a
little NITRIC ACID on the surface of the glass and spread it
around with the mop. Flush the surface with water, then place
the glass face down in a basin of clean water, to keep it clean
until you are ready to treat it.
Get five (5) clean glasses. In one make Solution A, by
dissolving one ounce of SILVER NITRATE in ten ounces of
DISTILLED WATER. Set aside one ounce of this solution to use
later. Then, with a medicine dropper and constant stirring with
a glass rod, "ammoniate" your Solution A, by adding, drop by
drop, some strong 10% to 26% AQUA AMMONIA. At first a thick,
brownish mass will appear, but as more ammonia is added this
will begin to thin out. Stop adding ammonia when the solution
has become just barely cloudy, not entirely clear.
Next, in a separate container, mix one ounce of caustic potash,
known as POTASSIUM HYDROXIDE, with 10 1/2 ounces of water.
Note: slowly add the caustic to the water. NEVER add water to
the caustic. Pour this solution into the ammoniated silver
nitrate solution and stir very thoroughly.
Then again, add strong ammonia water, drop by drop, until the
solution, just clears. Now, pour the remainder of the
Non-Ammoniated Silver Nitrate solution, this is the portion
originally set aside. The main solution would once again become
slightly cloudy. Make a solution of 1/2 ounce of GLUCOSE in ten
ounces of Distilled Water and stir it into the main solution,
which is now ready to use. This glucose is also know as
dextrose, or just plain corn sugar.
The "slivering" should be done on a level table. Remove the
glass from the basin and set it on edge to dry, then support it,
sterile face up, on the corners of four upturned identical
highball glasses, or the like. Place a small mirror, under the
glass, at an angle (this will enable you to see the reflection
of the silvering process so that you can stop at the right time).
Pour enough solution on the glass to cover it, leave it
undisturbed until the desired film of silver has been deposited.
By looking at the mirror which you have placed on the table, at
a slight angle, facing upwards, you are able to see the
reflection of the silvering process and stop at the moment when
the right degree of reflection and transparency has been
achieved. This will usually be about 20 minutes.
Then tip off the solution at one corner and thoroughly flush
with running water. Set the glass on edge and let drain dry.
WITHOUT touching the delicate film. When thoroughly dry, put on
a coat of clear VARNISH with a soft CAMEL-HAIR BRUSH, or better,
with a spray gun. When this dries, you may choose to further
protect the silvering by taping to the transparent mirror
another sheet of plain, clean glass of the same size.
In use, the light on the mirror side should be stronger than on
the back, and you should be able to see everything clearly
through the mirror from the back; while anyone on the other side
sees nothing but an ordinary mirror. Should you not be able to
see clearly through the mirror, you have allowed the silvering
process to continue too long. In order to achieve perfection,
practice with small mirrors, until you have the timing just
right. Such mirrors, as small as 8"x12" have sold for as much
as $12, which is of course far more than your cost to make.
Good Luck!
- Sold as information only -
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